<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/linux.git/virt, branch v6.19.11</title>
<subtitle>Linux kernel stable tree (mirror)</subtitle>
<id>https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.11</id>
<link rel='self' href='https://git.radix-linux.su/kernel/linux.git/atom?h=v6.19.11'/>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/'/>
<updated>2026-01-14T21:17:14+00:00</updated>
<entry>
<title>KVM: Don't clobber irqfd routing type when deassigning irqfd</title>
<updated>2026-01-14T21:17:14+00:00</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2026-01-13T17:46:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=b4d37cdb77a0015f51fee083598fa227cc07aaf1'/>
<id>urn:sha1:b4d37cdb77a0015f51fee083598fa227cc07aaf1</id>
<content type='text'>
When deassigning a KVM_IRQFD, don't clobber the irqfd's copy of the IRQ's
routing entry as doing so breaks kvm_arch_irq_bypass_del_producer() on x86
and arm64, which explicitly look for KVM_IRQ_ROUTING_MSI.  Instead, to
handle a concurrent routing update, verify that the irqfd is still active
before consuming the routing information.  As evidenced by the x86 and
arm64 bugs, and another bug in kvm_arch_update_irqfd_routing() (see below),
clobbering the entry type without notifying arch code is surprising and
error prone.

As a bonus, checking that the irqfd is active provides a convenient
location for documenting _why_ KVM must not consume the routing entry for
an irqfd that is in the process of being deassigned: once the irqfd is
deleted from the list (which happens *before* the eventfd is detached), it
will no longer receive updates via kvm_irq_routing_update(), and so KVM
could deliver an event using stale routing information (relative to
KVM_SET_GSI_ROUTING returning to userspace).

As an even better bonus, explicitly checking for the irqfd being active
fixes a similar bug to the one the clobbering is trying to prevent: if an
irqfd is deactivated, and then its routing is changed,
kvm_irq_routing_update() won't invoke kvm_arch_update_irqfd_routing()
(because the irqfd isn't in the list).  And so if the irqfd is in bypass
mode, IRQs will continue to be posted using the old routing information.

As for kvm_arch_irq_bypass_del_producer(), clobbering the routing type
results in KVM incorrectly keeping the IRQ in bypass mode, which is
especially problematic on AMD as KVM tracks IRQs that are being posted to
a vCPU in a list whose lifetime is tied to the irqfd.

Without the help of KASAN to detect use-after-free, the most common
sympton on AMD is a NULL pointer deref in amd_iommu_update_ga() due to
the memory for irqfd structure being re-allocated and zeroed, resulting
in irqfd-&gt;irq_bypass_data being NULL when read by
avic_update_iommu_vcpu_affinity():

  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 40cf2b9067 P4D 40cf2b9067 PUD 408362a067 PMD 0
  Oops: Oops: 0000 [#1] SMP
  CPU: 6 UID: 0 PID: 40383 Comm: vfio_irq_test
  Tainted: G     U  W  O        6.19.0-smp--5dddc257e6b2-irqfd #31 NONE
  Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE
  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025
  RIP: 0010:amd_iommu_update_ga+0x19/0xe0
  Call Trace:
   &lt;TASK&gt;
   avic_update_iommu_vcpu_affinity+0x3d/0x90 [kvm_amd]
   __avic_vcpu_load+0xf4/0x130 [kvm_amd]
   kvm_arch_vcpu_load+0x89/0x210 [kvm]
   vcpu_load+0x30/0x40 [kvm]
   kvm_arch_vcpu_ioctl_run+0x45/0x620 [kvm]
   kvm_vcpu_ioctl+0x571/0x6a0 [kvm]
   __se_sys_ioctl+0x6d/0xb0
   do_syscall_64+0x6f/0x9d0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
  RIP: 0033:0x46893b
    &lt;/TASK&gt;
  ---[ end trace 0000000000000000 ]---

If AVIC is inhibited when the irfd is deassigned, the bug will manifest as
list corruption, e.g. on the next irqfd assignment.

  list_add corruption. next-&gt;prev should be prev (ffff8d474d5cd588),
                       but was 0000000000000000. (next=ffff8d8658f86530).
  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:31!
  Oops: invalid opcode: 0000 [#1] SMP
  CPU: 128 UID: 0 PID: 80818 Comm: vfio_irq_test
  Tainted: G     U  W  O        6.19.0-smp--f19dc4d680ba-irqfd #28 NONE
  Tainted: [U]=USER, [W]=WARN, [O]=OOT_MODULE
  Hardware name: Google, Inc. Arcadia_IT_80/Arcadia_IT_80, BIOS 34.78.2-0 09/05/2025
  RIP: 0010:__list_add_valid_or_report+0x97/0xc0
  Call Trace:
   &lt;TASK&gt;
   avic_pi_update_irte+0x28e/0x2b0 [kvm_amd]
   kvm_pi_update_irte+0xbf/0x190 [kvm]
   kvm_arch_irq_bypass_add_producer+0x72/0x90 [kvm]
   irq_bypass_register_consumer+0xcd/0x170 [irqbypass]
   kvm_irqfd+0x4c6/0x540 [kvm]
   kvm_vm_ioctl+0x118/0x5d0 [kvm]
   __se_sys_ioctl+0x6d/0xb0
   do_syscall_64+0x6f/0x9d0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   &lt;/TASK&gt;
  ---[ end trace 0000000000000000 ]---

On Intel and arm64, the bug is less noisy, as the end result is that the
device keeps posting IRQs to the vCPU even after it's been deassigned.

Note, the worst of the breakage can be traced back to commit cb210737675e
("KVM: Pass new routing entries and irqfd when updating IRTEs"), as before
that commit KVM would pull the routing information from the per-VM routing
table.  But as above, similar bugs have existed since support for IRQ
bypass was added.  E.g. if a routing change finished before irq_shutdown()
invoked kvm_arch_irq_bypass_del_producer(), VMX and SVM would see stale
routing information and potentially leave the irqfd in bypass mode.

Alternatively, x86 could be fixed by explicitly checking irq_bypass_vcpu
instead of irq_entry.type in kvm_arch_irq_bypass_del_producer(), and arm64
could be modified to utilize irq_bypass_vcpu in a similar manner.  But (a)
that wouldn't fix the routing updates bug, and (b) fixing core code doesn't
preclude x86 (or arm64) from adding such code as a sanity check (spoiler
alert).

Fixes: f70c20aaf141 ("KVM: Add an arch specific hooks in 'struct kvm_kernel_irqfd'")
Fixes: cb210737675e ("KVM: Pass new routing entries and irqfd when updating IRTEs")
Fixes: a0d7e2fc61ab ("KVM: arm64: vgic-v4: Only attempt vLPI mapping for actual MSIs")
Cc: stable@vger.kernel.org
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Oliver Upton &lt;oupton@kernel.org&gt;
Link: https://patch.msgid.link/20260113174606.104978-2-seanjc@google.com
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'kvm-x86-fixes-6.19-rc1' of https://github.com/kvm-x86/linux into HEAD</title>
<updated>2025-12-18T17:38:45+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-12-18T17:38:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=0499add8efd72456514c6218c062911ccc922a99'/>
<id>urn:sha1:0499add8efd72456514c6218c062911ccc922a99</id>
<content type='text'>
KVM fixes for 6.19-rc1

 - Add a missing "break" to fix param parsing in the rseq selftest.

 - Apply runtime updates to the _current_ CPUID when userspace is setting
   CPUID, e.g. as part of vCPU hotplug, to fix a false positive and to avoid
   dropping the pending update.

 - Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot, as it's not
   supported by KVM and leads to a use-after-free due to KVM failing to unbind
   the memslot from the previously-associated guest_memfd instance.

 - Harden against similar KVM_MEM_GUEST_MEMFD goofs, and prepare for supporting
   flags-only changes on KVM_MEM_GUEST_MEMFD memlslots, e.g. for dirty logging.

 - Set exit_code[63:32] to -1 (all 0xffs) when synthesizing a nested
   SVM_EXIT_ERR (a.k.a. VMEXIT_INVALID) #VMEXIT, as VMEXIT_INVALID is defined
   as -1ull (a 64-bit value).

 - Update SVI when activating APICv to fix a bug where a post-activation EOI
   for an in-service IRQ would effective be lost due to SVI being stale.

 - Immediately refresh APICv controls (if necessary) on a nested VM-Exit
   instead of deferring the update via KVM_REQ_APICV_UPDATE, as the request is
   effectively ignored because KVM thinks the vCPU already has the correct
   APICv settings.
</content>
</entry>
<entry>
<title>Merge tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc</title>
<updated>2025-12-06T01:29:04+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-12-06T01:29:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=208eed95fc710827b100266c9450ae84d46727bd'/>
<id>urn:sha1:208eed95fc710827b100266c9450ae84d46727bd</id>
<content type='text'>
Pull SoC driver updates from Arnd Bergmann:
 "This is the first half of the driver changes:

   - A treewide interface change to the "syscore" operations for power
     management, as a preparation for future Tegra specific changes

   - Reset controller updates with added drivers for LAN969x, eic770 and
     RZ/G3S SoCs

   - Protection of system controller registers on Renesas and Google
     SoCs, to prevent trivially triggering a system crash from e.g.
     debugfs access

   - soc_device identification updates on Nvidia, Exynos and Mediatek

   - debugfs support in the ST STM32 firewall driver

   - Minor updates for SoC drivers on AMD/Xilinx, Renesas, Allwinner, TI

   - Cleanups for memory controller support on Nvidia and Renesas"

* tag 'soc-drivers-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (114 commits)
  memory: tegra186-emc: Fix missing put_bpmp
  Documentation: reset: Remove reset_controller_add_lookup()
  reset: fix BIT macro reference
  reset: rzg2l-usbphy-ctrl: Fix a NULL vs IS_ERR() bug in probe
  reset: th1520: Support reset controllers in more subsystems
  reset: th1520: Prepare for supporting multiple controllers
  dt-bindings: reset: thead,th1520-reset: Add controllers for more subsys
  dt-bindings: reset: thead,th1520-reset: Remove non-VO-subsystem resets
  reset: remove legacy reset lookup code
  clk: davinci: psc: drop unused reset lookup
  reset: rzg2l-usbphy-ctrl: Add support for RZ/G3S SoC
  reset: rzg2l-usbphy-ctrl: Add support for USB PWRRDY
  dt-bindings: reset: renesas,rzg2l-usbphy-ctrl: Document RZ/G3S support
  reset: eswin: Add eic7700 reset driver
  dt-bindings: reset: eswin: Documentation for eic7700 SoC
  reset: sparx5: add LAN969x support
  dt-bindings: reset: microchip: Add LAN969x support
  soc: rockchip: grf: Add select correct PWM implementation on RK3368
  soc/tegra: pmc: Add USB wake events for Tegra234
  amba: tegra-ahb: Fix device leak on SMMU enable
  ...
</content>
</entry>
<entry>
<title>Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm</title>
<updated>2025-12-06T01:01:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-12-06T01:01:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=51d90a15fedf8366cb96ef68d0ea2d0bf15417d2'/>
<id>urn:sha1:51d90a15fedf8366cb96ef68d0ea2d0bf15417d2</id>
<content type='text'>
Pull KVM updates from Paolo Bonzini:
 "ARM:

   - Support for userspace handling of synchronous external aborts
     (SEAs), allowing the VMM to potentially handle the abort in a
     non-fatal manner

   - Large rework of the VGIC's list register handling with the goal of
     supporting more active/pending IRQs than available list registers
     in hardware. In addition, the VGIC now supports EOImode==1 style
     deactivations for IRQs which may occur on a separate vCPU than the
     one that acked the IRQ

   - Support for FEAT_XNX (user / privileged execute permissions) and
     FEAT_HAF (hardware update to the Access Flag) in the software page
     table walkers and shadow MMU

   - Allow page table destruction to reschedule, fixing long
     need_resched latencies observed when destroying a large VM

   - Minor fixes to KVM and selftests

  Loongarch:

   - Get VM PMU capability from HW GCFG register

   - Add AVEC basic support

   - Use 64-bit register definition for EIOINTC

   - Add KVM timer test cases for tools/selftests

  RISC/V:

   - SBI message passing (MPXY) support for KVM guest

   - Give a new, more specific error subcode for the case when in-kernel
     AIA virtualization fails to allocate IMSIC VS-file

   - Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
     in small chunks

   - Fix guest page fault within HLV* instructions

   - Flush VS-stage TLB after VCPU migration for Andes cores

  s390:

   - Always allocate ESCA (Extended System Control Area), instead of
     starting with the basic SCA and converting to ESCA with the
     addition of the 65th vCPU. The price is increased number of exits
     (and worse performance) on z10 and earlier processor; ESCA was
     introduced by z114/z196 in 2010

   - VIRT_XFER_TO_GUEST_WORK support

   - Operation exception forwarding support

   - Cleanups

  x86:

   - Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO
     SPTE caching is disabled, as there can't be any relevant SPTEs to
     zap

   - Relocate a misplaced export

   - Fix an async #PF bug where KVM would clear the completion queue
     when the guest transitioned in and out of paging mode, e.g. when
     handling an SMI and then returning to paged mode via RSM

   - Leave KVM's user-return notifier registered even when disabling
     virtualization, as long as kvm.ko is loaded. On reboot/shutdown,
     keeping the notifier registered is ok; the kernel does not use the
     MSRs and the callback will run cleanly and restore host MSRs if the
     CPU manages to return to userspace before the system goes down

   - Use the checked version of {get,put}_user()

   - Fix a long-lurking bug where KVM's lack of catch-up logic for
     periodic APIC timers can result in a hard lockup in the host

   - Revert the periodic kvmclock sync logic now that KVM doesn't use a
     clocksource that's subject to NTP corrections

   - Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the
     latter behind CONFIG_CPU_MITIGATIONS

   - Context switch XCR0, XSS, and PKRU outside of the entry/exit fast
     path; the only reason they were handled in the fast path was to
     paper of a bug in the core #MC code, and that has long since been
     fixed

   - Add emulator support for AVX MOV instructions, to play nice with
     emulated devices whose guest drivers like to access PCI BARs with
     large multi-byte instructions

  x86 (AMD):

   - Fix a few missing "VMCB dirty" bugs

   - Fix the worst of KVM's lack of EFER.LMSLE emulation

   - Add AVIC support for addressing 4k vCPUs in x2AVIC mode

   - Fix incorrect handling of selective CR0 writes when checking
     intercepts during emulation of L2 instructions

   - Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32]
     on VMRUN and #VMEXIT

   - Fix a bug where KVM corrupt the guest code stream when re-injecting
     a soft interrupt if the guest patched the underlying code after the
     VM-Exit, e.g. when Linux patches code with a temporary INT3

   - Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits
     to userspace, and extend KVM "support" to all policy bits that
     don't require any actual support from KVM

  x86 (Intel):

   - Use the root role from kvm_mmu_page to construct EPTPs instead of
     the current vCPU state, partly as worthwhile cleanup, but mostly to
     pave the way for tracking per-root TLB flushes, and elide EPT
     flushes on pCPU migration if the root is clean from a previous
     flush

   - Add a few missing nested consistency checks

   - Rip out support for doing "early" consistency checks via hardware
     as the functionality hasn't been used in years and is no longer
     useful in general; replace it with an off-by-default module param
     to WARN if hardware fails a check that KVM does not perform

   - Fix a currently-benign bug where KVM would drop the guest's
     SPEC_CTRL[63:32] on VM-Enter

   - Misc cleanups

   - Overhaul the TDX code to address systemic races where KVM (acting
     on behalf of userspace) could inadvertantly trigger lock contention
     in the TDX-Module; KVM was either working around these in weird,
     ugly ways, or was simply oblivious to them (though even Yan's
     devilish selftests could only break individual VMs, not the host
     kernel)

   - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a
     TDX vCPU, if creating said vCPU failed partway through

   - Fix a few sparse warnings (bad annotation, 0 != NULL)

   - Use struct_size() to simplify copying TDX capabilities to userspace

   - Fix a bug where TDX would effectively corrupt user-return MSR
     values if the TDX Module rejects VP.ENTER and thus doesn't clobber
     host MSRs as expected

  Selftests:

   - Fix a math goof in mmu_stress_test when running on a single-CPU
     system/VM

   - Forcefully override ARCH from x86_64 to x86 to play nice with
     specifying ARCH=x86_64 on the command line

   - Extend a bunch of nested VMX to validate nested SVM as well

   - Add support for LA57 in the core VM_MODE_xxx macro, and add a test
     to verify KVM can save/restore nested VMX state when L1 is using
     5-level paging, but L2 is not

   - Clean up the guest paging code in anticipation of sharing the core
     logic for nested EPT and nested NPT

  guest_memfd:

   - Add NUMA mempolicy support for guest_memfd, and clean up a variety
     of rough edges in guest_memfd along the way

   - Define a CLASS to automatically handle get+put when grabbing a
     guest_memfd from a memslot to make it harder to leak references

   - Enhance KVM selftests to make it easer to develop and debug
     selftests like those added for guest_memfd NUMA support, e.g. where
     test and/or KVM bugs often result in hard-to-debug SIGBUS errors

   - Misc cleanups

  Generic:

   - Use the recently-added WQ_PERCPU when creating the per-CPU
     workqueue for irqfd cleanup

   - Fix a goof in the dirty ring documentation

   - Fix choice of target for directed yield across different calls to
     kvm_vcpu_on_spin(); the function was always starting from the first
     vCPU instead of continuing the round-robin search"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (260 commits)
  KVM: arm64: at: Update AF on software walk only if VM has FEAT_HAFDBS
  KVM: arm64: at: Use correct HA bit in TCR_EL2 when regime is EL2
  KVM: arm64: Document KVM_PGTABLE_PROT_{UX,PX}
  KVM: arm64: Fix spelling mistake "Unexpeced" -&gt; "Unexpected"
  KVM: arm64: Add break to default case in kvm_pgtable_stage2_pte_prot()
  KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()
  KVM: arm64: Fix compilation when CONFIG_ARM64_USE_LSE_ATOMICS=n
  KVM: arm64: selftests: Add test for AT emulation
  KVM: arm64: nv: Expose hardware access flag management to NV guests
  KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW
  KVM: arm64: Implement HW access flag management in stage-1 SW PTW
  KVM: arm64: Propagate PTW errors up to AT emulation
  KVM: arm64: Add helper for swapping guest descriptor
  KVM: arm64: nv: Use pgtable definitions in stage-2 walk
  KVM: arm64: Handle endianness in read helper for emulated PTW
  KVM: arm64: nv: Stop passing vCPU through void ptr in S2 PTW
  KVM: arm64: Call helper for reading descriptors directly
  KVM: arm64: nv: Advertise support for FEAT_XNX
  KVM: arm64: Teach ptdump about FEAT_XNX permissions
  KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions
  ...
</content>
</entry>
<entry>
<title>KVM: Harden and prepare for modifying existing guest_memfd memslots</title>
<updated>2025-12-02T16:49:37+00:00</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2025-12-02T02:03:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=af62fe2494da84eb01752282c8228c9bb3fe9f67'/>
<id>urn:sha1:af62fe2494da84eb01752282c8228c9bb3fe9f67</id>
<content type='text'>
Unbind guest_memfd memslots if KVM commits a MOVE or FLAGS_ONLY memslot
change to harden against use-after-free, and to prepare for eventually
supporting dirty logging on guest_memfd memslots, at which point
FLAGS_ONLY changes will be expected/supported.

Add two separate WARNs, once to yell if a guest_memfd memslot is moved
(which KVM is never expected to allow/support), and again if the unbind()
is triggered, to help detect uAPI goofs prior to deliberately allowing
FLAGS_ONLY changes.

Link: https://patch.msgid.link/20251202020334.1171351-3-seanjc@google.com
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</content>
</entry>
<entry>
<title>KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot</title>
<updated>2025-12-02T16:49:37+00:00</updated>
<author>
<name>Sean Christopherson</name>
<email>seanjc@google.com</email>
</author>
<published>2025-12-02T02:03:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9935df5333aa503a18de5071f53762b65c783c4c'/>
<id>urn:sha1:9935df5333aa503a18de5071f53762b65c783c4c</id>
<content type='text'>
Reject attempts to disable KVM_MEM_GUEST_MEMFD on a memslot that was
initially created with a guest_memfd binding, as KVM doesn't support
toggling KVM_MEM_GUEST_MEMFD on existing memslots.  KVM prevents enabling
KVM_MEM_GUEST_MEMFD, but doesn't prevent clearing the flag.

Failure to reject the new memslot results in a use-after-free due to KVM
not unbinding from the guest_memfd instance.  Unbinding on a FLAGS_ONLY
change is easy enough, and can/will be done as a hardening measure (in
anticipation of KVM supporting dirty logging on guest_memfd at some point),
but fixing the use-after-free would only address the immediate symptom.

  ==================================================================
  BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x362/0x400 [kvm]
  Write of size 8 at addr ffff8881111ae908 by task repro/745

  CPU: 7 UID: 1000 PID: 745 Comm: repro Not tainted 6.18.0-rc6-115d5de2eef3-next-kasan #3 NONE
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  Call Trace:
   &lt;TASK&gt;
   dump_stack_lvl+0x51/0x60
   print_report+0xcb/0x5c0
   kasan_report+0xb4/0xe0
   kvm_gmem_release+0x362/0x400 [kvm]
   __fput+0x2fa/0x9d0
   task_work_run+0x12c/0x200
   do_exit+0x6ae/0x2100
   do_group_exit+0xa8/0x230
   __x64_sys_exit_group+0x3a/0x50
   x64_sys_call+0x737/0x740
   do_syscall_64+0x5b/0x900
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
  RIP: 0033:0x7f581f2eac31
   &lt;/TASK&gt;

  Allocated by task 745 on cpu 6 at 9.746971s:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x13/0x50
   __kasan_kmalloc+0x77/0x90
   kvm_set_memory_region.part.0+0x652/0x1110 [kvm]
   kvm_vm_ioctl+0x14b0/0x3290 [kvm]
   __x64_sys_ioctl+0x129/0x1a0
   do_syscall_64+0x5b/0x900
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

  Freed by task 745 on cpu 6 at 9.747467s:
   kasan_save_stack+0x20/0x40
   kasan_save_track+0x13/0x50
   __kasan_save_free_info+0x37/0x50
   __kasan_slab_free+0x3b/0x60
   kfree+0xf5/0x440
   kvm_set_memslot+0x3c2/0x1160 [kvm]
   kvm_set_memory_region.part.0+0x86a/0x1110 [kvm]
   kvm_vm_ioctl+0x14b0/0x3290 [kvm]
   __x64_sys_ioctl+0x129/0x1a0
   do_syscall_64+0x5b/0x900
   entry_SYSCALL_64_after_hwframe+0x4b/0x53

Reported-by: Alexander Potapenko &lt;glider@google.com&gt;
Fixes: a7800aa80ea4 ("KVM: Add KVM_CREATE_GUEST_MEMFD ioctl() for guest-specific backing memory")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251202020334.1171351-2-seanjc@google.com
Signed-off-by: Sean Christopherson &lt;seanjc@google.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2025-12-02T16:48:53+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2025-12-02T16:48:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=2b09f480f0a1e68111ae36a7be9aa1c93e067255'/>
<id>urn:sha1:2b09f480f0a1e68111ae36a7be9aa1c93e067255</id>
<content type='text'>
Pull rseq updates from Thomas Gleixner:
 "A large overhaul of the restartable sequences and CID management:

  The recent enablement of RSEQ in glibc resulted in regressions which
  are caused by the related overhead. It turned out that the decision to
  invoke the exit to user work was not really a decision. More or less
  each context switch caused that. There is a long list of small issues
  which sums up nicely and results in a 3-4% regression in I/O
  benchmarks.

  The other detail which caused issues due to extra work in context
  switch and task migration is the CID (memory context ID) management.
  It also requires to use a task work to consolidate the CID space,
  which is executed in the context of an arbitrary task and results in
  sporadic uncontrolled exit latencies.

  The rewrite addresses this by:

   - Removing deprecated and long unsupported functionality

   - Moving the related data into dedicated data structures which are
     optimized for fast path processing.

   - Caching values so actual decisions can be made

   - Replacing the current implementation with a optimized inlined
     variant.

   - Separating fast and slow path for architectures which use the
     generic entry code, so that only fault and error handling goes into
     the TIF_NOTIFY_RESUME handler.

   - Rewriting the CID management so that it becomes mostly invisible in
     the context switch path. That moves the work of switching modes
     into the fork/exit path, which is a reasonable tradeoff. That work
     is only required when a process creates more threads than the
     cpuset it is allowed to run on or when enough threads exit after
     that. An artificial thread pool benchmarks which triggers this did
     not degrade, it actually improved significantly.

     The main effect in migration heavy scenarios is that runqueue lock
     held time and therefore contention goes down significantly"

* tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  sched/mmcid: Switch over to the new mechanism
  sched/mmcid: Implement deferred mode change
  irqwork: Move data struct to a types header
  sched/mmcid: Provide CID ownership mode fixup functions
  sched/mmcid: Provide new scheduler CID mechanism
  sched/mmcid: Introduce per task/CPU ownership infrastructure
  sched/mmcid: Serialize sched_mm_cid_fork()/exit() with a mutex
  sched/mmcid: Provide precomputed maximal value
  sched/mmcid: Move initialization out of line
  signal: Move MMCID exit out of sighand lock
  sched/mmcid: Convert mm CID mask to a bitmap
  cpumask: Cache num_possible_cpus()
  sched/mmcid: Use cpumask_weighted_or()
  cpumask: Introduce cpumask_weighted_or()
  sched/mmcid: Prevent pointless work in mm_update_cpus_allowed()
  sched/mmcid: Move scheduler code out of global header
  sched: Fixup whitespace damage
  sched/mmcid: Cacheline align MM CID storage
  sched/mmcid: Use proper data structures
  sched/mmcid: Revert the complex CID management
  ...
</content>
</entry>
<entry>
<title>Merge tag 'kvm-x86-tdx-6.19' of https://github.com/kvm-x86/linux into HEAD</title>
<updated>2025-11-26T08:36:37+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-11-26T08:36:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=de8e8ebb1a7c5e2243fdb0409418484501e3b9b2'/>
<id>urn:sha1:de8e8ebb1a7c5e2243fdb0409418484501e3b9b2</id>
<content type='text'>
KVM TDX changes for 6.19:

 - Overhaul the TDX code to address systemic races where KVM (acting on behalf
   of userspace) could inadvertantly trigger lock contention in the TDX-Module,
   which KVM was either working around in weird, ugly ways, or was simply
   oblivious to (as proven by Yan tripping several KVM_BUG_ON()s with clever
   selftests).

 - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a vCPU if
   creating said vCPU failed partway through.

 - Fix a few sparse warnings (bad annotation, 0 != NULL).

 - Use struct_size() to simplify copying capabilities to userspace.
</content>
</entry>
<entry>
<title>Merge tag 'kvm-x86-gmem-6.19' of https://github.com/kvm-x86/linux into HEAD</title>
<updated>2025-11-26T08:32:44+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-11-26T08:32:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=236831743ced9162a8953aa281b73c65bd68b822'/>
<id>urn:sha1:236831743ced9162a8953aa281b73c65bd68b822</id>
<content type='text'>
KVM guest_memfd changes for 6.19:

 - Add NUMA mempolicy support for guest_memfd, and clean up a variety of
   rough edges in guest_memfd along the way.

 - Define a CLASS to automatically handle get+put when grabbing a guest_memfd
   from a memslot to make it harder to leak references.

 - Enhance KVM selftests to make it easer to develop and debug selftests like
   those added for guest_memfd NUMA support, e.g. where test and/or KVM bugs
   often result in hard-to-debug SIGBUS errors.

 - Misc cleanups.
</content>
</entry>
<entry>
<title>Merge tag 'kvm-x86-generic-6.19' of https://github.com/kvm-x86/linux into HEAD</title>
<updated>2025-11-26T08:22:45+00:00</updated>
<author>
<name>Paolo Bonzini</name>
<email>pbonzini@redhat.com</email>
</author>
<published>2025-11-26T08:22:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.radix-linux.su/kernel/linux.git/commit/?id=9aca52b5523aab9c9a777a591c0b27acbede9881'/>
<id>urn:sha1:9aca52b5523aab9c9a777a591c0b27acbede9881</id>
<content type='text'>
KVM generic changes for 6.19:

 - Use the recently-added WQ_PERCPU when creating the per-CPU workqueue for
   irqfd cleanup.

 - Fix a goof in the dirty ring documentation.
</content>
</entry>
</feed>
