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[ Upstream commit 7de086909365cd60a5619a45af3f4152516fd75c ]
We have seen many crashes on powerpc hosts while loading bpf programs.
The problem here is that bpf_int_jit_compile() does a first pass
to compute the program length.
Then it allocates memory to store the generated program and
calls bpf_jit_build_body() a second time (and a third time
later)
What I have observed is that the second bpf_jit_build_body()
could end up using few more words than expected.
If bpf_jit_binary_alloc() put the space for the program
at the end of the allocated page, we then write on
a non mapped memory.
It appears that bpf_jit_emit_tail_call() calls
bpf_jit_emit_common_epilogue() while ctx->seen might not
be stable.
Only after the second pass we can be sure ctx->seen wont be changed.
Trying to avoid a second pass seems quite complex and probably
not worth it.
Fixes: ce0761419faef ("powerpc/bpf: Implement support for tail calls")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191101033444.143741-1-edumazet@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit af2e8c68b9c5403f77096969c516f742f5bb29e0 upstream.
On some systems that are vulnerable to Spectre v2, it is up to
software to flush the link stack (return address stack), in order to
protect against Spectre-RSB.
When exiting from a guest we do some house keeping and then
potentially exit to C code which is several stack frames deep in the
host kernel. We will then execute a series of returns without
preceeding calls, opening up the possiblity that the guest could have
poisoned the link stack, and direct speculative execution of the host
to a gadget of some sort.
To prevent this we add a flush of the link stack on exit from a guest.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 39e72bf96f5847ba87cc5bd7a3ce0fed813dc9ad upstream.
In commit ee13cb249fab ("powerpc/64s: Add support for software count
cache flush"), I added support for software to flush the count
cache (indirect branch cache) on context switch if firmware told us
that was the required mitigation for Spectre v2.
As part of that code we also added a software flush of the link
stack (return address stack), which protects against Spectre-RSB
between user processes.
That is all correct for CPUs that activate that mitigation, which is
currently Power9 Nimbus DD2.3.
What I got wrong is that on older CPUs, where firmware has disabled
the count cache, we also need to flush the link stack on context
switch.
To fix it we create a new feature bit which is not set by firmware,
which tells us we need to flush the link stack. We set that when
firmware tells us that either of the existing Spectre v2 mitigations
are enabled.
Then we adjust the patching code so that if we see that feature bit we
enable the link stack flush. If we're also told to flush the count
cache in software then we fall through and do that also.
On the older CPUs we don't need to do do the software count cache
flush, firmware has disabled it, so in that case we patch in an early
return after the link stack flush.
The naming of some of the functions is awkward after this patch,
because they're called "count cache" but they also do link stack. But
we'll fix that up in a later commit to ease backporting.
This is the fix for CVE-2019-18660.
Reported-by: Anthony Steinhauser <asteinhauser@google.com>
Fixes: ee13cb249fab ("powerpc/64s: Add support for software count cache flush")
Cc: stable@vger.kernel.org # v4.4+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d8f0e0b073e1ec52a05f0c2a56318b47387d2f10 upstream.
Add support for disabling the kernel implemented spectre v2 mitigation
(count cache flush on context switch) via the nospectre_v2 and
mitigations=off cmdline options.
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190524024647.381-1-cmr@informatik.wtf
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 833b45de69a6016c4b0cebe6765d526a31a81580 upstream.
The largepages debugfs entry is incremented/decremented as shadow
pages are created or destroyed. Clearing it will result in an
underflow, which is harmless to KVM but ugly (and could be
misinterpreted by tools that use debugfs information), so make
this particular statistic read-only.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm-ppc@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d10f60ae27d26d811e2a1bb39ded47df96d7499f ]
Make sure starting addr is aligned to segment boundary so that when
incrementing the segment, the starting address of the new segment is
below the end address. Otherwise the last segment might get missed.
Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/067a1b09f15f421d40797c2d04c22d4049a1cee8.1571071875.git.christophe.leroy@c-s.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7d6475051fb3d9339c5c760ed9883bc0a9048b21 ]
Commit e78a7614f3876 ("idle: Prevent late-arriving interrupts from
disrupting offline") changes arch_cpu_idle_dead to be called with
interrupts disabled, which triggers the WARN in pnv_smp_cpu_kill_self.
Fix this by fixing up irq_happened after hard disabling, rather than
requiring there are no pending interrupts, similarly to what was done
done until commit 2525db04d1cc5 ("powerpc/powernv: Simplify lazy IRQ
handling in CPU offline").
Fixes: e78a7614f3876 ("idle: Prevent late-arriving interrupts from disrupting offline")
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add unexpected_mask rather than checking for known bad values,
change the WARN_ON() to a WARN_ON_ONCE()]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191022115814.22456-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 12ade69c1eb9958b13374edf5ef742ea20ccffde upstream.
Connecting a vCPU to a XIVE KVM device means establishing a 1:1
association between a vCPU id and the offset (VP id) of a VP
structure within a fixed size block of VPs. We currently try to
enforce the 1:1 relationship by checking that a vCPU with the
same id isn't already connected. This is good but unfortunately
not enough because we don't map VP ids to raw vCPU ids but to
packed vCPU ids, and the packing function kvmppc_pack_vcpu_id()
isn't bijective by design. We got away with it because QEMU passes
vCPU ids that fit well in the packing pattern. But nothing prevents
userspace to come up with a forged vCPU id resulting in a packed id
collision which causes the KVM device to associate two vCPUs to the
same VP. This greatly confuses the irq layer and ultimately crashes
the kernel, as shown below.
Example: a guest with 1 guest thread per core, a core stride of
8 and 300 vCPUs has vCPU ids 0,8,16...2392. If QEMU is patched to
inject at some point an invalid vCPU id 348, which is the packed
version of itself and 2392, we get:
genirq: Flags mismatch irq 199. 00010000 (kvm-2-2392) vs. 00010000 (kvm-2-348)
CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ #38
Call Trace:
[c000003f7f9937e0] [c000000000c0110c] dump_stack+0xb0/0xf4 (unreliable)
[c000003f7f993820] [c0000000001cb480] __setup_irq+0xa70/0xad0
[c000003f7f9938d0] [c0000000001cb75c] request_threaded_irq+0x13c/0x260
[c000003f7f993940] [c00800000d44e7ac] kvmppc_xive_attach_escalation+0x104/0x270 [kvm]
[c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm]
[c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm]
[c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm]
[c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30
[c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120
[c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80
[c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68
xive-kvm: Failed to request escalation interrupt for queue 0 of VCPU 2392
------------[ cut here ]------------
remove_proc_entry: removing non-empty directory 'irq/199', leaking at least 'kvm-2-348'
WARNING: CPU: 24 PID: 88176 at /home/greg/Work/linux/kernel-kvm-ppc/fs/proc/generic.c:684 remove_proc_entry+0x1ec/0x200
Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm]
CPU: 24 PID: 88176 Comm: qemu-system-ppc Not tainted 5.3.0-xive-nr-servers-5.3-gku+ #38
NIP: c00000000053b0cc LR: c00000000053b0c8 CTR: c0000000000ba3b0
REGS: c000003f7f9934b0 TRAP: 0700 Not tainted (5.3.0-xive-nr-servers-5.3-gku+)
MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 48228222 XER: 20040000
CFAR: c000000000131a50 IRQMASK: 0
GPR00: c00000000053b0c8 c000003f7f993740 c0000000015ec500 0000000000000057
GPR04: 0000000000000001 0000000000000000 000049fb98484262 0000000000001bcf
GPR08: 0000000000000007 0000000000000007 0000000000000001 9000000000001033
GPR12: 0000000000008000 c000003ffffeb800 0000000000000000 000000012f4ce5a1
GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000
GPR20: 000000012f45d918 c000003f863758b0 c000003f86375870 0000000000000006
GPR24: c000003f86375a30 0000000000000007 c0002039373d9020 c0000000014c4a48
GPR28: 0000000000000001 c000003fe62a4f6b c00020394b2e9fab c000003fe62a4ec0
NIP [c00000000053b0cc] remove_proc_entry+0x1ec/0x200
LR [c00000000053b0c8] remove_proc_entry+0x1e8/0x200
Call Trace:
[c000003f7f993740] [c00000000053b0c8] remove_proc_entry+0x1e8/0x200 (unreliable)
[c000003f7f9937e0] [c0000000001d3654] unregister_irq_proc+0x114/0x150
[c000003f7f993880] [c0000000001c6284] free_desc+0x54/0xb0
[c000003f7f9938c0] [c0000000001c65ec] irq_free_descs+0xac/0x100
[c000003f7f993910] [c0000000001d1ff8] irq_dispose_mapping+0x68/0x80
[c000003f7f993940] [c00800000d44e8a4] kvmppc_xive_attach_escalation+0x1fc/0x270 [kvm]
[c000003f7f9939d0] [c00800000d45013c] kvmppc_xive_connect_vcpu+0x424/0x620 [kvm]
[c000003f7f993ac0] [c00800000d444428] kvm_arch_vcpu_ioctl+0x260/0x448 [kvm]
[c000003f7f993b90] [c00800000d43593c] kvm_vcpu_ioctl+0x154/0x7c8 [kvm]
[c000003f7f993d00] [c0000000004840f0] do_vfs_ioctl+0xe0/0xc30
[c000003f7f993db0] [c000000000484d44] ksys_ioctl+0x104/0x120
[c000003f7f993e00] [c000000000484d88] sys_ioctl+0x28/0x80
[c000003f7f993e20] [c00000000000b278] system_call+0x5c/0x68
Instruction dump:
2c230000 41820008 3923ff78 e8e900a0 3c82ff69 3c62ff8d 7fa6eb78 7fc5f378
3884f080 3863b948 4bbf6925 60000000 <0fe00000> 4bffff7c fba10088 4bbf6e41
---[ end trace b925b67a74a1d8d1 ]---
BUG: Kernel NULL pointer dereference at 0x00000010
Faulting instruction address: 0xc00800000d44fc04
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix MMU=Hash SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in: kvm_hv kvm dm_mod vhost_net vhost tap xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 ipt_REJECT nf_reject_ipv4 tun bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter squashfs loop fuse i2c_dev sg ofpart ocxl powernv_flash at24 xts mtd uio_pdrv_genirq vmx_crypto opal_prd ipmi_powernv uio ipmi_devintf ipmi_msghandler ibmpowernv ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ip_tables ext4 mbcache jbd2 raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor xor async_tx raid6_pq libcrc32c raid1 raid0 linear sd_mod ast i2c_algo_bit drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm ahci libahci libata tg3 drm_panel_orientation_quirks [last unloaded: kvm]
CPU: 24 PID: 88176 Comm: qemu-system-ppc Tainted: G W 5.3.0-xive-nr-servers-5.3-gku+ #38
NIP: c00800000d44fc04 LR: c00800000d44fc00 CTR: c0000000001cd970
REGS: c000003f7f9938e0 TRAP: 0300 Tainted: G W (5.3.0-xive-nr-servers-5.3-gku+)
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: 24228882 XER: 20040000
CFAR: c0000000001cd9ac DAR: 0000000000000010 DSISR: 40000000 IRQMASK: 0
GPR00: c00800000d44fc00 c000003f7f993b70 c00800000d468300 0000000000000000
GPR04: 00000000000000c7 0000000000000000 0000000000000000 c000003ffacd06d8
GPR08: 0000000000000000 c000003ffacd0738 0000000000000000 fffffffffffffffd
GPR12: 0000000000000040 c000003ffffeb800 0000000000000000 000000012f4ce5a1
GPR16: 000000012ef5a0c8 0000000000000000 000000012f113bb0 0000000000000000
GPR20: 000000012f45d918 00007ffffe0d9a80 000000012f4f5df0 000000012ef8c9f8
GPR24: 0000000000000001 0000000000000000 c000003fe4501ed0 c000003f8b1d0000
GPR28: c0000033314689c0 c000003fe4501c00 c000003fe4501e70 c000003fe4501e90
NIP [c00800000d44fc04] kvmppc_xive_cleanup_vcpu+0xfc/0x210 [kvm]
LR [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm]
Call Trace:
[c000003f7f993b70] [c00800000d44fc00] kvmppc_xive_cleanup_vcpu+0xf8/0x210 [kvm] (unreliable)
[c000003f7f993bd0] [c00800000d450bd4] kvmppc_xive_release+0xdc/0x1b0 [kvm]
[c000003f7f993c30] [c00800000d436a98] kvm_device_release+0xb0/0x110 [kvm]
[c000003f7f993c70] [c00000000046730c] __fput+0xec/0x320
[c000003f7f993cd0] [c000000000164ae0] task_work_run+0x150/0x1c0
[c000003f7f993d30] [c000000000025034] do_notify_resume+0x304/0x440
[c000003f7f993e20] [c00000000000dcc4] ret_from_except_lite+0x70/0x74
Instruction dump:
3bff0008 7fbfd040 419e0054 847e0004 2fa30000 419effec e93d0000 8929203c
2f890000 419effb8 4800821d e8410018 <e9230010> e9490008 9b2a0039 7c0004ac
---[ end trace b925b67a74a1d8d2 ]---
Kernel panic - not syncing: Fatal exception
This affects both XIVE and XICS-on-XIVE devices since the beginning.
Check the VP id instead of the vCPU id when a new vCPU is connected.
The allocation of the XIVE CPU structure in kvmppc_xive_connect_vcpu()
is moved after the check to avoid the need for rollback.
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cf387d9644d8c78721cf9b77af9f67bb5b04da16 upstream.
With PFN_MODE_PMEM namespace, the memmap area is allocated from the device
area. Some architectures map the memmap area with large page size. On
architectures like ppc64, 16MB page for memap mapping can map 262144 pfns.
This maps a namespace size of 16G.
When populating memmap region with 16MB page from the device area,
make sure the allocated space is not used to map resources outside this
namespace. Such usage of device area will prevent a namespace destroy.
Add resource end pnf in altmap and use that to check if the memmap area
allocation can map pfn outside the namespace. On ppc64 in such case we fallback
to allocation from memory.
This fix kernel crash reported below:
[ 132.034989] WARNING: CPU: 13 PID: 13719 at mm/memremap.c:133 devm_memremap_pages_release+0x2d8/0x2e0
[ 133.464754] BUG: Unable to handle kernel data access at 0xc00c00010b204000
[ 133.464760] Faulting instruction address: 0xc00000000007580c
[ 133.464766] Oops: Kernel access of bad area, sig: 11 [#1]
[ 133.464771] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
.....
[ 133.464901] NIP [c00000000007580c] vmemmap_free+0x2ac/0x3d0
[ 133.464906] LR [c0000000000757f8] vmemmap_free+0x298/0x3d0
[ 133.464910] Call Trace:
[ 133.464914] [c000007cbfd0f7b0] [c0000000000757f8] vmemmap_free+0x298/0x3d0 (unreliable)
[ 133.464921] [c000007cbfd0f8d0] [c000000000370a44] section_deactivate+0x1a4/0x240
[ 133.464928] [c000007cbfd0f980] [c000000000386270] __remove_pages+0x3a0/0x590
[ 133.464935] [c000007cbfd0fa50] [c000000000074158] arch_remove_memory+0x88/0x160
[ 133.464942] [c000007cbfd0fae0] [c0000000003be8c0] devm_memremap_pages_release+0x150/0x2e0
[ 133.464949] [c000007cbfd0fb70] [c000000000738ea0] devm_action_release+0x30/0x50
[ 133.464955] [c000007cbfd0fb90] [c00000000073a5a4] release_nodes+0x344/0x400
[ 133.464961] [c000007cbfd0fc40] [c00000000073378c] device_release_driver_internal+0x15c/0x250
[ 133.464968] [c000007cbfd0fc80] [c00000000072fd14] unbind_store+0x104/0x110
[ 133.464973] [c000007cbfd0fcd0] [c00000000072ee24] drv_attr_store+0x44/0x70
[ 133.464981] [c000007cbfd0fcf0] [c0000000004a32bc] sysfs_kf_write+0x6c/0xa0
[ 133.464987] [c000007cbfd0fd10] [c0000000004a1dfc] kernfs_fop_write+0x17c/0x250
[ 133.464993] [c000007cbfd0fd60] [c0000000003c348c] __vfs_write+0x3c/0x70
[ 133.464999] [c000007cbfd0fd80] [c0000000003c75d0] vfs_write+0xd0/0x250
djbw: Aneesh notes that this crash can likely be triggered in any kernel that
supports 'papr_scm', so flagging that commit for -stable consideration.
Fixes: b5beae5e224f ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: <stable@vger.kernel.org>
Reported-by: Sachin Sant <sachinp@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
Tested-by: Santosh Sivaraj <santosh@fossix.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Link: https://lore.kernel.org/r/20190910062826.10041-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 047e6575aec71d75b765c22111820c4776cd1c43 upstream.
On POWER9, under some circumstances, a broadcast TLB invalidation will
fail to invalidate the ERAT cache on some threads when there are
parallel mtpidr/mtlpidr happening on other threads of the same core.
This can cause stores to continue to go to a page after it's unmapped.
The workaround is to force an ERAT flush using PID=0 or LPID=0 tlbie
flush. This additional TLB flush will cause the ERAT cache
invalidation. Since we are using PID=0 or LPID=0, we don't get
filtered out by the TLB snoop filtering logic.
We need to still follow this up with another tlbie to take care of
store vs tlbie ordering issue explained in commit:
a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on
POWER9"). The presence of ERAT cache implies we can still get new
stores and they may miss store queue marking flush.
Cc: stable@vger.kernel.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-3-aneesh.kumar@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit cbd18991e24fea2c31da3bb117c83e4a3538cd11 upstream.
Uncompressing Kernel Image ... OK
Loading Device Tree to 01ff7000, end 01fff74f ... OK
[ 0.000000] printk: bootconsole [udbg0] enabled
[ 0.000000] BUG: Unable to handle kernel data access at 0xf818c000
[ 0.000000] Faulting instruction address: 0xc0013c7c
[ 0.000000] Thread overran stack, or stack corrupted
[ 0.000000] Oops: Kernel access of bad area, sig: 11 [#1]
[ 0.000000] BE PAGE_SIZE=16K PREEMPT
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty #2080
[ 0.000000] NIP: c0013c7c LR: c0013310 CTR: 00000000
[ 0.000000] REGS: c0c5ff38 TRAP: 0300 Not tainted (5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty)
[ 0.000000] MSR: 00001032 <ME,IR,DR,RI> CR: 99033955 XER: 80002100
[ 0.000000] DAR: f818c000 DSISR: 82000000
[ 0.000000] GPR00: c0013310 c0c5fff0 c0ad6ac0 c0c600c0 f818c031 82000000 00000000 ffffffff
[ 0.000000] GPR08: 00000000 f1f1f1f1 c0013c2c c0013304 99033955 00400008 00000000 07ff9598
[ 0.000000] GPR16: 00000000 07ffb94c 00000000 00000000 00000000 00000000 00000000 f818cfb2
[ 0.000000] GPR24: 00000000 00000000 00001000 ffffffff 00000000 c07dbf80 00000000 f818c000
[ 0.000000] NIP [c0013c7c] do_page_fault+0x50/0x904
[ 0.000000] LR [c0013310] handle_page_fault+0xc/0x38
[ 0.000000] Call Trace:
[ 0.000000] Instruction dump:
[ 0.000000] be010080 91410014 553fe8fe 3d40c001 3d20f1f1 7d800026 394a3c2c 3fffe000
[ 0.000000] 6129f1f1 900100c4 9181007c 91410018 <913f0000> 3d2001f4 6129f4f4 913f0004
Don't map the early shadow page read-only yet when creating the new
page tables for the real shadow memory, otherwise the memblock
allocations that immediately follows to create the real shadow pages
that are about to replace the early shadow page trigger a page fault
if they fall into the region being worked on at the moment.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/fe86886fb8db44360417cee0dc515ad47ca6ef72.1566382750.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4c0f5d1eb4072871c34530358df45f05ab80edd6 upstream.
In a couple of places there is a need to select whether read-only
protection of shadow pages is performed with PAGE_KERNEL_RO or with
PAGE_READONLY.
Add a helper to avoid duplicating the choice.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: stable@vger.kernel.org
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9f33f44b9cd741c4a02b3dce7b8ef9438fe2cd2a.1566382750.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 09ce98cacd51fcd0fa0af2f79d1e1d3192f4cbb0 upstream.
Rename the #define to indicate this is related to store vs tlbie
ordering issue. In the next patch, we will be adding another feature
flag that is used to handles ERAT flush vs tlbie ordering issue.
Fixes: a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on POWER9")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-2-aneesh.kumar@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 677733e296b5c7a37c47da391fc70a43dc40bd67 upstream.
The store ordering vs tlbie issue mentioned in commit
a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on
POWER9") is fixed for Nimbus 2.3 and Cumulus 1.3 revisions. We don't
need to apply the fixup if we are running on them
We can only do this on PowerNV. On pseries guest with KVM we still
don't support redoing the feature fixup after migration. So we should
be enabling all the workarounds needed, because whe can possibly
migrate between DD 2.3 and DD 2.2
Fixes: a5d4b5891c2f ("powerpc/mm: Fixup tlbie vs store ordering issue on POWER9")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190924035254.24612-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 663c0c9496a69f80011205ba3194049bcafd681d upstream.
When loading modules, from time to time an Oops is encountered during
the init of shadow area for globals. This is due to the last page not
always being mapped depending on the exact distance between the start
and the end of the shadow area and the alignment with the page
addresses.
Fix this by aligning the starting address with the page address.
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Erhard F. <erhard_f@mailbox.org>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/4f887e9b77d0d725cbb52035c7ece485c1c5fc14.1565361881.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 45ff3c55958542c3b76075d59741297b8cb31cbb upstream.
Parallel loading of modules may lead to bad setup of shadow page table
entries.
First, lets align modules so that two modules never share the same
shadow page.
Second, ensure that two modules cannot allocate two page tables for
the same PMD entry at the same time. This is done by using
init_mm.page_table_lock in the same way as __pte_alloc_kernel()
Fixes: 2edb16efc899 ("powerpc/32: Add KASAN support")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c97284f912128cbc3f2fe09d68e90e65fb3e6026.1565361876.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 56090a3902c80c296e822d11acdb6a101b322c52 upstream.
pnv_tce() returns a pointer to a TCE entry and originally a TCE table
would be pre-allocated. For the default case of 2GB window the table
needs only a single level and that is fine. However if more levels are
requested, it is possible to get a race when 2 threads want a pointer
to a TCE entry from the same page of TCEs.
This adds cmpxchg to handle the race. Note that once TCE is non-zero,
it cannot become zero again.
Fixes: a68bd1267b72 ("powerpc/powernv/ioda: Allocate indirect TCE levels on demand")
CC: stable@vger.kernel.org # v4.19+
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190718051139.74787-2-aik@ozlabs.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c784be435d5dae28d3b03db31753dd7a18733f0c upstream.
The calls to arch_add_memory()/arch_remove_memory() are always made
with the read-side cpu_hotplug_lock acquired via memory_hotplug_begin().
On pSeries, arch_add_memory()/arch_remove_memory() eventually call
resize_hpt() which in turn calls stop_machine() which acquires the
read-side cpu_hotplug_lock again, thereby resulting in the recursive
acquisition of this lock.
In the absence of CONFIG_PROVE_LOCKING, we hadn't observed a system
lockup during a memory hotplug operation because cpus_read_lock() is a
per-cpu rwsem read, which, in the fast-path (in the absence of the
writer, which in our case is a CPU-hotplug operation) simply
increments the read_count on the semaphore. Thus a recursive read in
the fast-path doesn't cause any problems.
However, we can hit this problem in practice if there is a concurrent
CPU-Hotplug operation in progress which is waiting to acquire the
write-side of the lock. This will cause the second recursive read to
block until the writer finishes. While the writer is blocked since the
first read holds the lock. Thus both the reader as well as the writers
fail to make any progress thereby blocking both CPU-Hotplug as well as
Memory Hotplug operations.
Memory-Hotplug CPU-Hotplug
CPU 0 CPU 1
------ ------
1. down_read(cpu_hotplug_lock.rw_sem)
[memory_hotplug_begin]
2. down_write(cpu_hotplug_lock.rw_sem)
[cpu_up/cpu_down]
3. down_read(cpu_hotplug_lock.rw_sem)
[stop_machine()]
Lockdep complains as follows in these code-paths.
swapper/0/1 is trying to acquire lock:
(____ptrval____) (cpu_hotplug_lock.rw_sem){++++}, at: stop_machine+0x2c/0x60
but task is already holding lock:
(____ptrval____) (cpu_hotplug_lock.rw_sem){++++}, at: mem_hotplug_begin+0x20/0x50
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(cpu_hotplug_lock.rw_sem);
lock(cpu_hotplug_lock.rw_sem);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by swapper/0/1:
#0: (____ptrval____) (&dev->mutex){....}, at: __driver_attach+0x12c/0x1b0
#1: (____ptrval____) (cpu_hotplug_lock.rw_sem){++++}, at: mem_hotplug_begin+0x20/0x50
#2: (____ptrval____) (mem_hotplug_lock.rw_sem){++++}, at: percpu_down_write+0x54/0x1a0
stack backtrace:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.0.0-rc5-58373-gbc99402235f3-dirty #166
Call Trace:
dump_stack+0xe8/0x164 (unreliable)
__lock_acquire+0x1110/0x1c70
lock_acquire+0x240/0x290
cpus_read_lock+0x64/0xf0
stop_machine+0x2c/0x60
pseries_lpar_resize_hpt+0x19c/0x2c0
resize_hpt_for_hotplug+0x70/0xd0
arch_add_memory+0x58/0xfc
devm_memremap_pages+0x5e8/0x8f0
pmem_attach_disk+0x764/0x830
nvdimm_bus_probe+0x118/0x240
really_probe+0x230/0x4b0
driver_probe_device+0x16c/0x1e0
__driver_attach+0x148/0x1b0
bus_for_each_dev+0x90/0x130
driver_attach+0x34/0x50
bus_add_driver+0x1a8/0x360
driver_register+0x108/0x170
__nd_driver_register+0xd0/0xf0
nd_pmem_driver_init+0x34/0x48
do_one_initcall+0x1e0/0x45c
kernel_init_freeable+0x540/0x64c
kernel_init+0x2c/0x160
ret_from_kernel_thread+0x5c/0x68
Fix this issue by
1) Requiring all the calls to pseries_lpar_resize_hpt() be made
with cpu_hotplug_lock held.
2) In pseries_lpar_resize_hpt() invoke stop_machine_cpuslocked()
as a consequence of 1)
3) To satisfy 1), in hpt_order_set(), call mmu_hash_ops.resize_hpt()
with cpu_hotplug_lock held.
Fixes: dbcf929c0062 ("powerpc/pseries: Add support for hash table resizing")
Cc: stable@vger.kernel.org # v4.11+
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1557906352-29048-1-git-send-email-ego@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit e7de4f7b64c23e503a8c42af98d56f2a7462bd6d upstream.
Currently the OPAL symbol map is globally readable, which seems bad as
it contains physical addresses.
Restrict it to root.
Fixes: c8742f85125d ("powerpc/powernv: Expose OPAL firmware symbol map")
Cc: stable@vger.kernel.org # v3.19+
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190503075253.22798-1-ajd@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7c7a532ba3fc51bf9527d191fb410786c1fdc73c upstream.
Commit 453d87f6a8ae ("powerpc/mm: Warn if W+X pages found on boot")
wrongly changed KERN_VIRT_START from 0 to PAGE_OFFSET, leading to a
shift in the displayed addresses.
Lets revert that change to resync walk_pagetables()'s addr val and
pgd_t pointer for PPC32.
Fixes: 453d87f6a8ae ("powerpc/mm: Warn if W+X pages found on boot")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/eb4d626514e22f85814830012642329018ef6af9.1565786091.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 9d6d712fbf7766f21c838940eebcd7b4d476c5e6 upstream.
When KASAN is selected, the definitive hash table has to be
set up later, but there is already an early temporary one.
When KASAN is not selected, there is no early hash table,
so the setup of the definitive hash table cannot be delayed.
Fixes: 72f208c6a8f7 ("powerpc/32s: move hash code patching out of MMU_init_hw()")
Cc: stable@vger.kernel.org # v5.2+
Reported-by: Jonathan Neuschafer <j.neuschaefer@gmx.net>
Tested-by: Jonathan Neuschafer <j.neuschaefer@gmx.net>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b7860c5e1e784d6b96ba67edf47dd6cbc2e78ab6.1565776892.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 415480dce2ef03bb8335deebd2f402f475443ce0 upstream.
If a page is already mapped RW without the DIRTY flag, the DIRTY
flag is never set and a TLB store miss exception is taken forever.
This is easily reproduced with the following app:
void main(void)
{
volatile char *ptr = mmap(0, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
*ptr = *ptr;
}
When DIRTY flag is not set, bail out of TLB miss handler and take
a minor page fault which will set the DIRTY flag.
Fixes: f8b58c64eaef ("powerpc/603: let's handle PAGE_DIRTY directly")
Cc: stable@vger.kernel.org # v5.1+
Reported-by: Doug Crawford <doug.crawford@intelight-its.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/80432f71194d7ee75b2f5043ecf1501cf1cca1f3.1566196646.git.christophe.leroy@c-s.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b5bda6263cad9a927e1a4edb7493d542da0c1410 upstream.
schedule_work() cannot be called from MCE exception context as MCE can
interrupt even in interrupt disabled context.
Fixes: 733e4a4c4467 ("powerpc/mce: hookup memory_failure for UE errors")
Cc: stable@vger.kernel.org # v4.15+
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820081352.8641-2-santosh@fossix.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 99ead78afd1128bfcebe7f88f3b102fb2da09aee upstream.
The current code would fail on huge pages addresses, since the shift would
be incorrect. Use the correct page shift value returned by
__find_linux_pte() to get the correct physical address. The code is more
generic and can handle both regular and compound pages.
Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors")
Signed-off-by: Balbir Singh <bsingharora@gmail.com>
[arbab@linux.ibm.com: Fixup pseries_do_memory_failure()]
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Tested-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Santosh Sivaraj <santosh@fossix.org>
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190820081352.8641-3-santosh@fossix.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit da15c03b047dca891d37b9f4ef9ca14d84a6484f upstream.
Testing has revealed the existence of a race condition where a XIVE
interrupt being shut down can be in one of the XIVE interrupt queues
(of which there are up to 8 per CPU, one for each priority) at the
point where free_irq() is called. If this happens, can return an
interrupt number which has been shut down. This can lead to various
symptoms:
- irq_to_desc(irq) can be NULL. In this case, no end-of-interrupt
function gets called, resulting in the CPU's elevated interrupt
priority (numerically lowered CPPR) never gets reset. That then
means that the CPU stops processing interrupts, causing device
timeouts and other errors in various device drivers.
- The irq descriptor or related data structures can be in the process
of being freed as the interrupt code is using them. This typically
leads to crashes due to bad pointer dereferences.
This race is basically what commit 62e0468650c3 ("genirq: Add optional
hardware synchronization for shutdown", 2019-06-28) is intended to
fix, given a get_irqchip_state() method for the interrupt controller
being used. It works by polling the interrupt controller when an
interrupt is being freed until the controller says it is not pending.
With XIVE, the PQ bits of the interrupt source indicate the state of
the interrupt source, and in particular the P bit goes from 0 to 1 at
the point where the hardware writes an entry into the interrupt queue
that this interrupt is directed towards. Normally, the code will then
process the interrupt and do an end-of-interrupt (EOI) operation which
will reset PQ to 00 (assuming another interrupt hasn't been generated
in the meantime). However, there are situations where the code resets
P even though a queue entry exists (for example, by setting PQ to 01,
which disables the interrupt source), and also situations where the
code leaves P at 1 after removing the queue entry (for example, this
is done for escalation interrupts so they cannot fire again until
they are explicitly re-enabled).
The code already has a 'saved_p' flag for the interrupt source which
indicates that a queue entry exists, although it isn't maintained
consistently. This patch adds a 'stale_p' flag to indicate that
P has been left at 1 after processing a queue entry, and adds code
to set and clear saved_p and stale_p as necessary to maintain a
consistent indication of whether a queue entry may or may not exist.
With this, we can implement xive_get_irqchip_state() by looking at
stale_p, saved_p and the ESB PQ bits for the interrupt.
There is some additional code to handle escalation interrupts
properly; because they are enabled and disabled in KVM assembly code,
which does not have access to the xive_irq_data struct for the
escalation interrupt. Hence, stale_p may be incorrect when the
escalation interrupt is freed in kvmppc_xive_{,native_}cleanup_vcpu().
Fortunately, we can fix it up by looking at vcpu->arch.xive_esc_on,
with some careful attention to barriers in order to ensure the correct
result if xive_esc_irq() races with kvmppc_xive_cleanup_vcpu().
Finally, this adds code to make noise on the console (pr_crit and
WARN_ON(1)) if we find an interrupt queue entry for an interrupt
which does not have a descriptor. While this won't catch the race
reliably, if it does get triggered it will be an indication that
the race is occurring and needs to be debugged.
Fixes: 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE interrupt controller")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190813100648.GE9567@blackberry
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit ff42df49e75f053a8a6b4c2533100cdcc23afe69 upstream.
On POWER9, when userspace reads the value of the DPDES register on a
vCPU, it is possible for 0 to be returned although there is a doorbell
interrupt pending for the vCPU. This can lead to a doorbell interrupt
being lost across migration. If the guest kernel uses doorbell
interrupts for IPIs, then it could malfunction because of the lost
interrupt.
This happens because a newly-generated doorbell interrupt is signalled
by setting vcpu->arch.doorbell_request to 1; the DPDES value in
vcpu->arch.vcore->dpdes is not updated, because it can only be updated
when holding the vcpu mutex, in order to avoid races.
To fix this, we OR in vcpu->arch.doorbell_request when reading the
DPDES value.
Cc: stable@vger.kernel.org # v4.13+
Fixes: 579006944e0d ("KVM: PPC: Book3S HV: Virtualize doorbell facility on POWER9")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d28eafc5a64045c78136162af9d4ba42f8230080 upstream.
When we are running multiple vcores on the same physical core, they
could be from different VMs and so it is possible that one of the
VMs could have its arch.mmu_ready flag cleared (for example by a
concurrent HPT resize) when we go to run it on a physical core.
We currently check the arch.mmu_ready flag for the primary vcore
but not the flags for the other vcores that will be run alongside
it. This adds that check, and also a check when we select the
secondary vcores from the preempted vcores list.
Cc: stable@vger.kernel.org # v4.14+
Fixes: 38c53af85306 ("KVM: PPC: Book3S HV: Fix exclusion between HPT resizing and other HPT updates")
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 959c5d5134786b4988b6fdd08e444aa67d1667ed upstream.
Escalation interrupts are interrupts sent to the host by the XIVE
hardware when it has an interrupt to deliver to a guest VCPU but that
VCPU is not running anywhere in the system. Hence we disable the
escalation interrupt for the VCPU being run when we enter the guest
and re-enable it when the guest does an H_CEDE hypercall indicating
it is idle.
It is possible that an escalation interrupt gets generated just as we
are entering the guest. In that case the escalation interrupt may be
using a queue entry in one of the interrupt queues, and that queue
entry may not have been processed when the guest exits with an H_CEDE.
The existing entry code detects this situation and does not clear the
vcpu->arch.xive_esc_on flag as an indication that there is a pending
queue entry (if the queue entry gets processed, xive_esc_irq() will
clear the flag). There is a comment in the code saying that if the
flag is still set on H_CEDE, we have to abort the cede rather than
re-enabling the escalation interrupt, lest we end up with two
occurrences of the escalation interrupt in the interrupt queue.
However, the exit code doesn't do that; it aborts the cede in the sense
that vcpu->arch.ceded gets cleared, but it still enables the escalation
interrupt by setting the source's PQ bits to 00. Instead we need to
set the PQ bits to 10, indicating that an interrupt has been triggered.
We also need to avoid setting vcpu->arch.xive_esc_on in this case
(i.e. vcpu->arch.xive_esc_on seen to be set on H_CEDE) because
xive_esc_irq() will run at some point and clear it, and if we race with
that we may end up with an incorrect result (i.e. xive_esc_on set when
the escalation interrupt has just been handled).
It is extremely unlikely that having two queue entries would cause
observable problems; theoretically it could cause queue overflow, but
the CPU would have to have thousands of interrupts targetted to it for
that to be possible. However, this fix will also make it possible to
determine accurately whether there is an unhandled escalation
interrupt in the queue, which will be needed by the following patch.
Fixes: 9b9b13a6d153 ("KVM: PPC: Book3S HV: Keep XIVE escalation interrupt masked unless ceded")
Cc: stable@vger.kernel.org # v4.16+
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190813100349.GD9567@blackberry
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8d4ba9c931bc384bcc6889a43915aaaf19d3e499 upstream.
At present, when running a guest on POWER9 using HV KVM but not using
an in-kernel interrupt controller (XICS or XIVE), for example if QEMU
is run with the kernel_irqchip=off option, the guest entry code goes
ahead and tries to load the guest context into the XIVE hardware, even
though no context has been set up.
To fix this, we check that the "CAM word" is non-zero before pushing
it to the hardware. The CAM word is initialized to a non-zero value
in kvmppc_xive_connect_vcpu() and kvmppc_xive_native_connect_vcpu(),
and is now cleared in kvmppc_xive_{,native_}cleanup_vcpu.
Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org # v4.12+
Reported-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190813100100.GC9567@blackberry
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 237aed48c642328ff0ab19b63423634340224a06 upstream.
When a vCPU is brought done, the XIVE VP (Virtual Processor) is first
disabled and then the event notification queues are freed. When freeing
the queues, we check for possible escalation interrupts and free them
also.
But when a XIVE VP is disabled, the underlying XIVE ENDs also are
disabled in OPAL. When an END (Event Notification Descriptor) is
disabled, its ESB pages (ESn and ESe) are disabled and loads return all
1s. Which means that any access on the ESB page of the escalation
interrupt will return invalid values.
When an interrupt is freed, the shutdown handler computes a 'saved_p'
field from the value returned by a load in xive_do_source_set_mask().
This value is incorrect for escalation interrupts for the reason
described above.
This has no impact on Linux/KVM today because we don't make use of it
but we will introduce in future changes a xive_get_irqchip_state()
handler. This handler will use the 'saved_p' field to return the state
of an interrupt and 'saved_p' being incorrect, softlockup will occur.
Fix the vCPU cleanup sequence by first freeing the escalation interrupts
if any, then disable the XIVE VP and last free the queues.
Fixes: 90c73795afa2 ("KVM: PPC: Book3S HV: Add a new KVM device for the XIVE native exploitation mode")
Fixes: 5af50993850a ("KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller")
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190806172538.5087-1-clg@kaod.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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functions
commit 2ad7a27deaf6d78545d97ab80874584f6990360e upstream.
There are some POWER9 machines where the OPAL firmware does not support
the OPAL_XIVE_GET_QUEUE_STATE and OPAL_XIVE_SET_QUEUE_STATE calls.
The impact of this is that a guest using XIVE natively will not be able
to be migrated successfully. On the source side, the get_attr operation
on the KVM native device for the KVM_DEV_XIVE_GRP_EQ_CONFIG attribute
will fail; on the destination side, the set_attr operation for the same
attribute will fail.
This adds tests for the existence of the OPAL get/set queue state
functions, and if they are not supported, the XIVE-native KVM device
is not created and the KVM_CAP_PPC_IRQ_XIVE capability returns false.
Userspace can then either provide a software emulation of XIVE, or
else tell the guest that it does not have a XIVE controller available
to it.
Cc: stable@vger.kernel.org # v5.2+
Fixes: 3fab2d10588e ("KVM: PPC: Book3S HV: XIVE: Activate XIVE exploitation mode")
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit e7ca44ed3ba77fc26cf32650bb71584896662474 ]
Since commit 4388c9b3a6ee ("powerpc: Do not send system reset request
through the oops path"), pstore dmesg file is not updated when dump is
triggered from HMC. This commit modified system reset (sreset) handler
to invoke fadump or kdump (if configured), without pushing dmesg to
pstore. This leaves pstore to have old dmesg data which won't be much
of a help if kdump fails to capture the dump. This patch fixes that by
calling kmsg_dump() before heading to fadump ot kdump.
Fixes: 4388c9b3a6ee ("powerpc: Do not send system reset request through the oops path")
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904075949.15607-1-ganeshgr@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 92c94dfb69e350471473fd3075c74bc68150879e ]
prep_irq_for_idle() is intended to be called before entering
H_CEDE (and it is used by the pseries cpuidle driver). However the
default pseries idle routine does not call it, leading to mismanaged
lazy irq state when the cpuidle driver isn't in use. Manifestations of
this include:
* Dropped IPIs in the time immediately after a cpu comes
online (before it has installed the cpuidle handler), making the
online operation block indefinitely waiting for the new cpu to
respond.
* Hitting this WARN_ON in arch_local_irq_restore():
/*
* We should already be hard disabled here. We had bugs
* where that wasn't the case so let's dbl check it and
* warn if we are wrong. Only do that when IRQ tracing
* is enabled as mfmsr() can be costly.
*/
if (WARN_ON_ONCE(mfmsr() & MSR_EE))
__hard_irq_disable();
Call prep_irq_for_idle() from pseries_lpar_idle() and honor its
result.
Fixes: 363edbe2614a ("powerpc: Default arch idle could cede processor on pseries")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190910225244.25056-1-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 799abe283e5103d48e079149579b4f167c95ea0e ]
When the last device in an eeh_pe is removed the eeh_pe structure itself
(and any empty parents) are freed since they are no longer needed. This
results in a crash when a hotplug driver is involved since the following
may occur:
1. Device is suprise removed.
2. Driver performs an MMIO, which fails and queues and eeh_event.
3. Hotplug driver receives a hotplug interrupt and removes any
pci_devs that were under the slot.
4. pci_dev is torn down and the eeh_pe is freed.
5. The EEH event handler thread processes the eeh_event and crashes
since the eeh_pe pointer in the eeh_event structure is no
longer valid.
Crashing is generally considered poor form. Instead of doing that use
the fact PEs are marked as EEH_PE_INVALID to keep them around until the
end of the recovery cycle, at which point we can safely prune any empty
PEs.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190903101605.2890-2-oohall@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0b66370c61fcf5fcc1d6901013e110284da6e2bb ]
Bare metal machine checks run an "early" handler in real mode before
running the main handler which reports the event.
The main handler runs exactly as a normal interrupt handler, after the
"windup" which sets registers back as they were at interrupt entry.
CFAR does not get restored by the windup code, so that will be wrong
when the handler is run.
Restore the CFAR to the saved value before running the late handler.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802105709.27696-8-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit aa06e3d60e245284d1e55497eb3108828092818d ]
The EEH_DEV_NO_HANDLER flag is used by the EEH system to prevent the
use of driver callbacks in drivers that have been bound part way
through the recovery process. This is necessary to prevent later stage
handlers from being called when the earlier stage handlers haven't,
which can be confusing for drivers.
However, the flag is set for all devices that are added after boot
time and only cleared at the end of the EEH recovery process. This
results in hot plugged devices erroneously having the flag set during
the first recovery after they are added (causing their driver's
handlers to be incorrectly ignored).
To remedy this, clear the flag at the beginning of recovery
processing. The flag is still cleared at the end of recovery
processing, although it is no longer really necessary.
Also clear the flag during eeh_handle_special_event(), for the same
reasons.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b8ca5629d27de74c957d4f4b250177d1b6fc4bbd.1565930772.git.sbobroff@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 10c4bd7cd28e77aeb8cfa65b23cb3c632ede2a49 ]
The alloc_pages_node return value should be tested for failure
before being passed to page_address.
Tested-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190724084638.24982-3-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit ccfb5bd71d3d1228090a8633800ae7cdf42a94ac ]
After a partition migration, pseries_devicetree_update() processes
changes to the device tree communicated from the platform to
Linux. This is a relatively heavyweight operation, with multiple
device tree searches, memory allocations, and conversations with
partition firmware.
There's a few levels of nested loops which are bounded only by
decisions made by the platform, outside of Linux's control, and indeed
we have seen RCU stalls on large systems while executing this call
graph. Use cond_resched() in these loops so that the cpu is yielded
when needed.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 8f51e3929470942e6a8744061254fdeef646cd36 ]
create_physical_mapping expects physical addresses, but creating and
splitting these mappings after boot is supplying virtual (effective)
addresses. This can be irritated by booting with mem= to limit memory
then probing an unused physical memory range:
echo <addr> > /sys/devices/system/memory/probe
This mostly works by accident, firstly because __va(__va(x)) == __va(x)
so the virtual address does not get corrupted. Secondly because pfn_pte
masks out the upper bits of the pfn beyond the physical address limit,
so a pfn constructed with a 0xc000000000000000 virtual linear address
will be masked back to the correct physical address in the pte.
Fixes: 6cc27341b21a8 ("powerpc/mm: add radix__create_section_mapping()")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190724084638.24982-1-npiggin@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 38a0d0cdb46d3f91534e5b9839ec2d67be14c59d ]
We see warnings such as:
kernel/futex.c: In function 'do_futex':
kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized]
return oldval == cmparg;
^
kernel/futex.c:1651:6: note: 'oldval' was declared here
int oldval, ret;
^
This is because arch_futex_atomic_op_inuser() only sets *oval if ret
is 0 and GCC doesn't see that it will only use it when ret is 0.
Anyway, the non-zero ret path is an error path that won't suffer from
setting *oval, and as *oval is a local var in futex_atomic_op_inuser()
it will have no impact.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: reword change log slightly]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/86b72f0c134367b214910b27b9a6dd3321af93bb.1565774657.git.christophe.leroy@c-s.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit e033829d2aaad85cb7cf46986c3be0bcc72f791e ]
walk_pagetables() always walk the entire pgdir from address 0
but considers PAGE_OFFSET or KERN_VIRT_START as the starting
address of the walk, resulting in a possible mismatch in the
displayed addresses.
Ex: on PPC32, when KERN_VIRT_START was locally defined as
PAGE_OFFSET, ptdump displayed 0x80000000
instead of 0xc0000000 for the first kernel page,
because 0xc0000000 + 0xc0000000 = 0x80000000
Start the walk at st->start_address instead of starting at 0.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5aa2ac513295f594cce8ddb1c649f61947bd063d.1565786091.git.christophe.leroy@c-s.fr
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a6717c01ddc259f6f73364779df058e2c67309f8 ]
The LPAR migration implementation and userspace-initiated cpu hotplug
can interleave their executions like so:
1. Set cpu 7 offline via sysfs.
2. Begin a partition migration, whose implementation requires the OS
to ensure all present cpus are online; cpu 7 is onlined:
rtas_ibm_suspend_me -> rtas_online_cpus_mask -> cpu_up
This sets cpu 7 online in all respects except for the cpu's
corresponding struct device; dev->offline remains true.
3. Set cpu 7 online via sysfs. _cpu_up() determines that cpu 7 is
already online and returns success. The driver core (device_online)
sets dev->offline = false.
4. The migration completes and restores cpu 7 to offline state:
rtas_ibm_suspend_me -> rtas_offline_cpus_mask -> cpu_down
This leaves cpu7 in a state where the driver core considers the cpu
device online, but in all other respects it is offline and
unused. Attempts to online the cpu via sysfs appear to succeed but the
driver core actually does not pass the request to the lower-level
cpuhp support code. This makes the cpu unusable until the cpu device
is manually set offline and then online again via sysfs.
Instead of directly calling cpu_up/cpu_down, the migration code should
use the higher-level device core APIs to maintain consistent state and
serialize operations.
Fixes: 120496ac2d2d ("powerpc: Bring all threads online prior to migration/hibernation")
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190802192926.19277-2-nathanl@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c3e0dbd7f780a58c4695f1cd8fc8afde80376737 ]
Currently, the xmon 'dx' command calls OPAL to dump the XIVE state in
the OPAL logs and also outputs some of the fields of the internal XIVE
structures in Linux. The OPAL calls can only be done on baremetal
(PowerNV) and they crash a pseries machine. Fix by checking the
hypervisor feature of the CPU.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190814154754.23682-2-clg@kaod.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
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window
[ Upstream commit c37c792dec0929dbb6360a609fb00fa20bb16fc2 ]
We allocate only the first level of multilevel TCE tables for KVM
already (alloc_userspace_copy==true), and the rest is allocated on demand.
This is not enabled though for bare metal.
This removes the KVM limitation (implicit, via the alloc_userspace_copy
parameter) and always allocates just the first level. The on-demand
allocation of missing levels is already implemented.
As from now on DMA map might happen with disabled interrupts, this
allocates TCEs with GFP_ATOMIC; otherwise lockdep reports errors 1].
In practice just a single page is allocated there so chances for failure
are quite low.
To save time when creating a new clean table, this skips non-allocated
indirect TCE entries in pnv_tce_free just like we already do in
the VFIO IOMMU TCE driver.
This changes the default level number from 1 to 2 to reduce the amount
of memory required for the default 32bit DMA window at the boot time.
The default window size is up to 2GB which requires 4MB of TCEs which is
unlikely to be used entirely or at all as most devices these days are
64bit capable so by switching to 2 levels by default we save 4032KB of
RAM per a device.
While at this, add __GFP_NOWARN to alloc_pages_node() as the userspace
can trigger this path via VFIO, see the failure and try creating a table
again with different parameters which might succeed.
[1]:
===
BUG: sleeping function called from invalid context at mm/page_alloc.c:4596
in_atomic(): 1, irqs_disabled(): 1, pid: 1038, name: scsi_eh_1
2 locks held by scsi_eh_1/1038:
#0: 000000005efd659a (&host->eh_mutex){+.+.}, at: ata_eh_acquire+0x34/0x80
#1: 0000000006cf56a6 (&(&host->lock)->rlock){....}, at: ata_exec_internal_sg+0xb0/0x5c0
irq event stamp: 500
hardirqs last enabled at (499): [<c000000000cb8a74>] _raw_spin_unlock_irqrestore+0x94/0xd0
hardirqs last disabled at (500): [<c000000000cb85c4>] _raw_spin_lock_irqsave+0x44/0x120
softirqs last enabled at (0): [<c000000000101120>] copy_process.isra.4.part.5+0x640/0x1a80
softirqs last disabled at (0): [<0000000000000000>] 0x0
CPU: 73 PID: 1038 Comm: scsi_eh_1 Not tainted 5.2.0-rc6-le_nv2_aikATfstn1-p1 #634
Call Trace:
[c000003d064cef50] [c000000000c8e6c4] dump_stack+0xe8/0x164 (unreliable)
[c000003d064cefa0] [c00000000014ed78] ___might_sleep+0x2f8/0x310
[c000003d064cf020] [c0000000003ca084] __alloc_pages_nodemask+0x2a4/0x1560
[c000003d064cf220] [c0000000000c2530] pnv_alloc_tce_level.isra.0+0x90/0x130
[c000003d064cf290] [c0000000000c2888] pnv_tce+0x128/0x3b0
[c000003d064cf360] [c0000000000c2c00] pnv_tce_build+0xb0/0xf0
[c000003d064cf3c0] [c0000000000bbd9c] pnv_ioda2_tce_build+0x3c/0xb0
[c000003d064cf400] [c00000000004cfe0] ppc_iommu_map_sg+0x210/0x550
[c000003d064cf510] [c00000000004b7a4] dma_iommu_map_sg+0x74/0xb0
[c000003d064cf530] [c000000000863944] ata_qc_issue+0x134/0x470
[c000003d064cf5b0] [c000000000863ec4] ata_exec_internal_sg+0x244/0x5c0
[c000003d064cf700] [c0000000008642d0] ata_exec_internal+0x90/0xe0
[c000003d064cf780] [c0000000008650ac] ata_dev_read_id+0x2ec/0x640
[c000003d064cf8d0] [c000000000878e28] ata_eh_recover+0x948/0x16d0
[c000003d064cfa10] [c00000000087d760] sata_pmp_error_handler+0x480/0xbf0
[c000003d064cfbc0] [c000000000884624] ahci_error_handler+0x74/0xe0
[c000003d064cfbf0] [c000000000879fa8] ata_scsi_port_error_handler+0x2d8/0x7c0
[c000003d064cfca0] [c00000000087a544] ata_scsi_error+0xb4/0x100
[c000003d064cfd00] [c000000000802450] scsi_error_handler+0x120/0x510
[c000003d064cfdb0] [c000000000140c48] kthread+0x1b8/0x1c0
[c000003d064cfe20] [c00000000000bd8c] ret_from_kernel_thread+0x5c/0x70
ata1: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
irq event stamp: 2305
========================================================
hardirqs last enabled at (2305): [<c00000000000e4c8>] fast_exc_return_irq+0x28/0x34
hardirqs last disabled at (2303): [<c000000000cb9fd0>] __do_softirq+0x4a0/0x654
WARNING: possible irq lock inversion dependency detected
5.2.0-rc6-le_nv2_aikATfstn1-p1 #634 Tainted: G W
softirqs last enabled at (2304): [<c000000000cba054>] __do_softirq+0x524/0x654
softirqs last disabled at (2297): [<c00000000010f278>] irq_exit+0x128/0x180
--------------------------------------------------------
swapper/0/0 just changed the state of lock:
0000000006cf56a6 (&(&host->lock)->rlock){-...}, at: ahci_single_level_irq_intr+0xac/0x120
but this lock took another, HARDIRQ-unsafe lock in the past:
(fs_reclaim){+.+.}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(fs_reclaim);
local_irq_disable();
lock(&(&host->lock)->rlock);
lock(fs_reclaim);
<Interrupt>
lock(&(&host->lock)->rlock);
*** DEADLOCK ***
no locks held by swapper/0/0.
the shortest dependencies between 2nd lock and 1st lock:
-> (fs_reclaim){+.+.} ops: 167579 {
HARDIRQ-ON-W at:
lock_acquire+0xf8/0x2a0
fs_reclaim_acquire.part.23+0x44/0x60
kmem_cache_alloc_node_trace+0x80/0x590
alloc_desc+0x64/0x270
__irq_alloc_descs+0x2e4/0x3a0
irq_domain_alloc_descs+0xb0/0x150
irq_create_mapping+0x168/0x2c0
xics_smp_probe+0x2c/0x98
pnv_smp_probe+0x40/0x9c
smp_prepare_cpus+0x524/0x6c4
kernel_init_freeable+0x1b4/0x650
kernel_init+0x2c/0x148
ret_from_kernel_thread+0x5c/0x70
SOFTIRQ-ON-W at:
lock_acquire+0xf8/0x2a0
fs_reclaim_acquire.part.23+0x44/0x60
kmem_cache_alloc_node_trace+0x80/0x590
alloc_desc+0x64/0x270
__irq_alloc_descs+0x2e4/0x3a0
irq_domain_alloc_descs+0xb0/0x150
irq_create_mapping+0x168/0x2c0
xics_smp_probe+0x2c/0x98
pnv_smp_probe+0x40/0x9c
smp_prepare_cpus+0x524/0x6c4
kernel_init_freeable+0x1b4/0x650
kernel_init+0x2c/0x148
ret_from_kernel_thread+0x5c/0x70
INITIAL USE at:
lock_acquire+0xf8/0x2a0
fs_reclaim_acquire.part.23+0x44/0x60
kmem_cache_alloc_node_trace+0x80/0x590
alloc_desc+0x64/0x270
__irq_alloc_descs+0x2e4/0x3a0
irq_domain_alloc_descs+0xb0/0x150
irq_create_mapping+0x168/0x2c0
xics_smp_probe+0x2c/0x98
pnv_smp_probe+0x40/0x9c
smp_prepare_cpus+0x524/0x6c4
kernel_init_freeable+0x1b4/0x650
kernel_init+0x2c/0x148
ret_from_kernel_thread+0x5c/0x70
}
===
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190718051139.74787-4-aik@ozlabs.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 41ba17f20ea835c489e77bd54e2da73184e22060 upstream.
Commit <684d984038aa> ('powerpc/powernv: Add debugfs interface for
imc-mode and imc') added debugfs interface for the nest imc pmu
devices to support changing of different ucode modes. Primarily adding
this capability for debug. But when doing so, the code did not
consider the case of cpu-less nodes. So when reading the _cmd_ or
_mode_ file of a cpu-less node will create this crash.
Faulting instruction address: 0xc0000000000d0d58
Oops: Kernel access of bad area, sig: 11 [#1]
...
CPU: 67 PID: 5301 Comm: cat Not tainted 5.2.0-rc6-next-20190627+ #19
NIP: c0000000000d0d58 LR: c00000000049aa18 CTR:c0000000000d0d50
REGS: c00020194548f9e0 TRAP: 0300 Not tainted (5.2.0-rc6-next-20190627+)
MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE> CR:28022822 XER: 00000000
CFAR: c00000000049aa14 DAR: 000000000003fc08 DSISR:40000000 IRQMASK: 0
...
NIP imc_mem_get+0x8/0x20
LR simple_attr_read+0x118/0x170
Call Trace:
simple_attr_read+0x70/0x170 (unreliable)
debugfs_attr_read+0x6c/0xb0
__vfs_read+0x3c/0x70
vfs_read+0xbc/0x1a0
ksys_read+0x7c/0x140
system_call+0x5c/0x70
Patch fixes the issue with a more robust check for vbase to NULL.
Before patch, ls output for the debugfs imc directory
# ls /sys/kernel/debug/powerpc/imc/
imc_cmd_0 imc_cmd_251 imc_cmd_253 imc_cmd_255 imc_mode_0 imc_mode_251 imc_mode_253 imc_mode_255
imc_cmd_250 imc_cmd_252 imc_cmd_254 imc_cmd_8 imc_mode_250 imc_mode_252 imc_mode_254 imc_mode_8
After patch, ls output for the debugfs imc directory
# ls /sys/kernel/debug/powerpc/imc/
imc_cmd_0 imc_cmd_8 imc_mode_0 imc_mode_8
Actual bug here is that, we have two loops with potentially different
loop counts. That is, in imc_get_mem_addr_nest(), loop count is
obtained from the dt entries. But in case of export_imc_mode_and_cmd(),
loop was based on for_each_nid() count. Patch fixes the loop count in
latter based on the struct mem_info. Ideally it would be better to
have array size in struct imc_pmu.
Fixes: 684d984038aa ('powerpc/powernv: Add debugfs interface for imc-mode and imc')
Reported-by: Qian Cai <cai@lca.pw>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190827101635.6942-1-maddy@linux.vnet.ibm.com
Cc: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 117acf5c29dd89e4c86761c365b9724dba0d9763 ]
Back in 2004 we added logic to arch/ppc64/Makefile to pass
the --synthetic option to nm, if it was supported by nm.
Then in 2005 when arch/ppc64 and arch/ppc were merged, the logic to
add --synthetic was moved inside an #ifdef CONFIG_PPC64 block within
arch/powerpc/Makefile, and has remained there since.
That was fine, though crufty, until recently when a change to
init/Kconfig added a config time check that uses $(NM). On powerpc
that leads to an infinite loop because Kconfig uses $(NM) to calculate
some values, then the powerpc Makefile changes $(NM), which Kconfig
notices and restarts.
The original commit that added --synthetic simply said:
On new toolchains we need to use nm --synthetic or we miss code
symbols.
And the nm man page says that the --synthetic option causes nm to:
Include synthetic symbols in the output. These are special symbols
created by the linker for various purposes.
So it seems safe to always pass --synthetic if nm supports it, ie. on
32-bit and 64-bit, it just means 32-bit kernels might have more
symbols reported (and in practice I see no extra symbols). Making it
unconditional avoids the #ifdef CONFIG_PPC64, which in turn avoids the
infinite loop.
Debugged-by: Peter Collingbourne <pcc@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 6ccb4ac2bf8a35c694ead92f8ac5530a16e8f2c8 upstream.
There's a bug in skiboot that causes the OPAL_XIVE_ALLOCATE_IRQ call
to return the 32-bit value 0xffffffff when OPAL has run out of IRQs.
Unfortunatelty, OPAL return values are signed 64-bit entities and
errors are supposed to be negative. If that happens, the linux code
confusingly treats 0xffffffff as a valid IRQ number and panics at some
point.
A fix was recently merged in skiboot:
e97391ae2bb5 ("xive: fix return value of opal_xive_allocate_irq()")
but we need a workaround anyway to support older skiboots already
in the field.
Internally convert 0xffffffff to OPAL_RESOURCE which is the usual error
returned upon resource exhaustion.
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/156821713818.1985334.14123187368108582810.stgit@bahia.lan
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
"One fix for a boot hang on some Freescale machines when PREEMPT is
enabled.
Two CVE fixes for bugs in our handling of FP registers and
transactional memory, both of which can result in corrupted FP state,
or FP state leaking between processes.
Thanks to: Chris Packham, Christophe Leroy, Gustavo Romero, Michael
Neuling"
* tag 'powerpc-5.3-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/tm: Fix restoring FP/VMX facility incorrectly on interrupts
powerpc/tm: Fix FP/VMX unavailable exceptions inside a transaction
powerpc/64e: Drop stale call to smp_processor_id() which hangs SMP startup
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When in userspace and MSR FP=0 the hardware FP state is unrelated to
the current process. This is extended for transactions where if tbegin
is run with FP=0, the hardware checkpoint FP state will also be
unrelated to the current process. Due to this, we need to ensure this
hardware checkpoint is updated with the correct state before we enable
FP for this process.
Unfortunately we get this wrong when returning to a process from a
hardware interrupt. A process that starts a transaction with FP=0 can
take an interrupt. When the kernel returns back to that process, we
change to FP=1 but with hardware checkpoint FP state not updated. If
this transaction is then rolled back, the FP registers now contain the
wrong state.
The process looks like this:
Userspace: Kernel
Start userspace
with MSR FP=0 TM=1
< -----
...
tbegin
bne
Hardware interrupt
---- >
<do_IRQ...>
....
ret_from_except
restore_math()
/* sees FP=0 */
restore_fp()
tm_active_with_fp()
/* sees FP=1 (Incorrect) */
load_fp_state()
FP = 0 -> 1
< -----
Return to userspace
with MSR TM=1 FP=1
with junk in the FP TM checkpoint
TM rollback
reads FP junk
When returning from the hardware exception, tm_active_with_fp() is
incorrectly making restore_fp() call load_fp_state() which is setting
FP=1.
The fix is to remove tm_active_with_fp().
tm_active_with_fp() is attempting to handle the case where FP state
has been changed inside a transaction. In this case the checkpointed
and transactional FP state is different and hence we must restore the
FP state (ie. we can't do lazy FP restore inside a transaction that's
used FP). It's safe to remove tm_active_with_fp() as this case is
handled by restore_tm_state(). restore_tm_state() detects if FP has
been using inside a transaction and will set load_fp and call
restore_math() to ensure the FP state (checkpoint and transaction) is
restored.
This is a data integrity problem for the current process as the FP
registers are corrupted. It's also a security problem as the FP
registers from one process may be leaked to another.
Similarly for VMX.
A simple testcase to replicate this will be posted to
tools/testing/selftests/powerpc/tm/tm-poison.c
This fixes CVE-2019-15031.
Fixes: a7771176b439 ("powerpc: Don't enable FP/Altivec if not checkpointed")
Cc: stable@vger.kernel.org # 4.15+
Signed-off-by: Gustavo Romero <gromero@linux.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904045529.23002-2-gromero@linux.vnet.ibm.com
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When we take an FP unavailable exception in a transaction we have to
account for the hardware FP TM checkpointed registers being
incorrect. In this case for this process we know the current and
checkpointed FP registers must be the same (since FP wasn't used
inside the transaction) hence in the thread_struct we copy the current
FP registers to the checkpointed ones.
This copy is done in tm_reclaim_thread(). We use thread->ckpt_regs.msr
to determine if FP was on when in userspace. thread->ckpt_regs.msr
represents the state of the MSR when exiting userspace. This is setup
by check_if_tm_restore_required().
Unfortunatley there is an optimisation in giveup_all() which returns
early if tsk->thread.regs->msr (via local variable `usermsr`) has
FP=VEC=VSX=SPE=0. This optimisation means that
check_if_tm_restore_required() is not called and hence
thread->ckpt_regs.msr is not updated and will contain an old value.
This can happen if due to load_fp=255 we start a userspace process
with MSR FP=1 and then we are context switched out. In this case
thread->ckpt_regs.msr will contain FP=1. If that same process is then
context switched in and load_fp overflows, MSR will have FP=0. If that
process now enters a transaction and does an FP instruction, the FP
unavailable will not update thread->ckpt_regs.msr (the bug) and MSR
FP=1 will be retained in thread->ckpt_regs.msr. tm_reclaim_thread()
will then not perform the required memcpy and the checkpointed FP regs
in the thread struct will contain the wrong values.
The code path for this happening is:
Userspace: Kernel
Start userspace
with MSR FP/VEC/VSX/SPE=0 TM=1
< -----
...
tbegin
bne
fp instruction
FP unavailable
---- >
fp_unavailable_tm()
tm_reclaim_current()
tm_reclaim_thread()
giveup_all()
return early since FP/VMX/VSX=0
/* ckpt MSR not updated (Incorrect) */
tm_reclaim()
/* thread_struct ckpt FP regs contain junk (OK) */
/* Sees ckpt MSR FP=1 (Incorrect) */
no memcpy() performed
/* thread_struct ckpt FP regs not fixed (Incorrect) */
tm_recheckpoint()
/* Put junk in hardware checkpoint FP regs */
....
< -----
Return to userspace
with MSR TM=1 FP=1
with junk in the FP TM checkpoint
TM rollback
reads FP junk
This is a data integrity problem for the current process as the FP
registers are corrupted. It's also a security problem as the FP
registers from one process may be leaked to another.
This patch moves up check_if_tm_restore_required() in giveup_all() to
ensure thread->ckpt_regs.msr is updated correctly.
A simple testcase to replicate this will be posted to
tools/testing/selftests/powerpc/tm/tm-poison.c
Similarly for VMX.
This fixes CVE-2019-15030.
Fixes: f48e91e87e67 ("powerpc/tm: Fix FP and VMX register corruption")
Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Gustavo Romero <gromero@linux.vnet.ibm.com>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190904045529.23002-1-gromero@linux.vnet.ibm.com
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