kernel/linux.git/drivers/tty/hvc, branch v5.4.113

tty: hvcs: Don't NULL tty->driver_data until hvcs_cleanup()

2020-10-29T08:57:38+00:00

[ Upstream commit 63ffcbdad738e3d1c857027789a2273df3337624 ] The code currently NULLs tty->driver_data in hvcs_close() with the intent of informing the next call to hvcs_open() that device needs to be reconfigured. However, when hvcs_cleanup() is called we copy hvcsd from tty->driver_data which was previoulsy NULLed by hvcs_close() and our call to tty_port_put(&hvcsd->port) doesn't actually do anything since &hvcsd->port ends up translating to NULL by chance. This has the side effect that when hvcs_remove() is called we have one too many port references preventing hvcs_destuct_port() from ever being called. This also prevents us from reusing the /dev/hvcsX node in a future hvcs_probe() and we can eventually run out of /dev/hvcsX devices. Fix this by waiting to NULL tty->driver_data in hvcs_cleanup(). Fixes: 27bf7c43a19c ("TTY: hvcs, add tty install") Signed-off-by: Tyrel Datwyler Link: https://lore.kernel.org/r/20200820234643.70412-1-tyreld@linux.ibm.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

Revert "tty: hvc: Fix data abort due to race in hvc_open"

2020-06-30T19:37:13+00:00

commit cf9c94456ebafc6d75a834e58dfdc8ae71a3acbc upstream. This reverts commit e2bd1dcbe1aa34ff5570b3427c530e4332ecf0fe. In discussion on the mailing list, it has been determined that this is not the correct type of fix for this issue. Revert it so that we can do this correctly. Reported-by: Jiri Slaby Reported-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Cc: Raghavendra Rao Ananta Signed-off-by: Greg Kroah-Hartman

tty: hvc: Fix data abort due to race in hvc_open

2020-06-24T15:50:22+00:00

[ Upstream commit e2bd1dcbe1aa34ff5570b3427c530e4332ecf0fe ] Potentially, hvc_open() can be called in parallel when two tasks calls open() on /dev/hvcX. In such a scenario, if the hp->ops->notifier_add() callback in the function fails, where it sets the tty->driver_data to NULL, the parallel hvc_open() can see this NULL and cause a memory abort. Hence, serialize hvc_open and check if tty->private_data is NULL before proceeding ahead. The issue can be easily reproduced by launching two tasks simultaneously that does nothing but open() and close() on /dev/hvcX. For example: $ ./simple_open_close /dev/hvc0 & ./simple_open_close /dev/hvc0 & Signed-off-by: Raghavendra Rao Ananta Link: https://lore.kernel.org/r/20200428032601.22127-1-rananta@codeaurora.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: hvc_console, fix crashes on parallel open/close

2020-06-10T18:24:56+00:00

commit 24eb2377f977fe06d84fca558f891f95bc28a449 upstream. hvc_open sets tty->driver_data to NULL when open fails at some point. Typically, the failure happens in hp->ops->notifier_add(). If there is a racing process which tries to open such mangled tty, which was not closed yet, the process will crash in hvc_open as tty->driver_data is NULL. All this happens because close wants to know whether open failed or not. But ->open should not NULL this and other tty fields for ->close to be happy. ->open should call tty_port_set_initialized(true) and close should check by tty_port_initialized() instead. So do this properly in this driver. So this patch removes these from ->open: * tty_port_tty_set(&hp->port, NULL). This happens on last close. * tty->driver_data = NULL. Dtto. * tty_port_put(&hp->port). This happens in shutdown and until now, this must have been causing a reference underflow, if I am not missing something. Signed-off-by: Jiri Slaby Cc: stable Reported-and-tested-by: Raghavendra Link: https://lore.kernel.org/r/20200526145632.13879-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: hvc: fix buffer overflow during hvc_alloc().

2020-04-29T14:33:17+00:00

commit 9a9fc42b86c06120744555fea43fdcabe297c656 upstream. If there is a lot(more then 16) of virtio-console devices or virtio_console module is reloaded - buffers 'vtermnos' and 'cons_ops' are overflowed. In older kernels it overruns spinlock which leads to kernel freezing: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 To reproduce the issue, you can try simple script that loads/unloads module. Something like this: while [ 1 ] do modprobe virtio_console sleep 2 modprobe -r virtio_console sleep 2 done Description of problem: Guest get 'Call Trace' when loading module "virtio_console" and unloading it frequently - clearly reproduced on kernel-4.18.0: [ 81.498208] ------------[ cut here ]------------ [ 81.499263] pvqspinlock: lock 0xffffffff92080020 has corrupted value 0xc0774ca0! [ 81.501000] WARNING: CPU: 0 PID: 785 at kernel/locking/qspinlock_paravirt.h:500 __pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.503173] Modules linked in: virtio_console fuse xt_CHECKSUM ipt_MASQUERADE xt_conntrack ipt_REJECT nft_counter nf_nat_tftp nft_objref nf_conntrack_tftp tun bridge stp llc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nft_chain_route_ipv6 nft_chain_nat_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack nft_chain_route_ipv4 ip6_tables nft_compat ip_set nf_tables nfnetlink sunrpc bochs_drm drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm i2c_piix4 pcspkr crct10dif_pclmul crc32_pclmul joydev ghash_clmulni_intel ip_tables xfs libcrc32c sd_mod sg ata_generic ata_piix virtio_net libata crc32c_intel net_failover failover serio_raw virtio_scsi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: virtio_console] [ 81.517019] CPU: 0 PID: 785 Comm: kworker/0:2 Kdump: loaded Not tainted 4.18.0-167.el8.x86_64 #1 [ 81.518639] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 81.520205] Workqueue: events control_work_handler [virtio_console] [ 81.521354] RIP: 0010:__pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.522450] Code: 07 00 48 63 7a 10 e8 bf 64 f5 ff 66 90 c3 8b 05 e6 cf d6 01 85 c0 74 01 c3 8b 17 48 89 fe 48 c7 c7 38 4b 29 91 e8 3a 6c fa ff <0f> 0b c3 0f 0b 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 [ 81.525830] RSP: 0018:ffffb51a01ffbd70 EFLAGS: 00010282 [ 81.526798] RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000000 [ 81.528110] RDX: ffff9e66f1826480 RSI: ffff9e66f1816a08 RDI: ffff9e66f1816a08 [ 81.529437] RBP: ffffffff9153ff10 R08: 000000000000026c R09: 0000000000000053 [ 81.530732] R10: 0000000000000000 R11: ffffb51a01ffbc18 R12: ffff9e66cd682200 [ 81.532133] R13: ffffffff9153ff10 R14: ffff9e6685569500 R15: ffff9e66cd682000 [ 81.533442] FS: 0000000000000000(0000) GS:ffff9e66f1800000(0000) knlGS:0000000000000000 [ 81.534914] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 81.535971] CR2: 00005624c55b14d0 CR3: 00000003a023c000 CR4: 00000000003406f0 [ 81.537283] Call Trace: [ 81.537763] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20 [ 81.539011] .slowpath+0x9/0xe [ 81.539585] hvc_alloc+0x25e/0x300 [ 81.540237] init_port_console+0x28/0x100 [virtio_console] [ 81.541251] handle_control_message.constprop.27+0x1c4/0x310 [virtio_console] [ 81.542546] control_work_handler+0x70/0x10c [virtio_console] [ 81.543601] process_one_work+0x1a7/0x3b0 [ 81.544356] worker_thread+0x30/0x390 [ 81.545025] ? create_worker+0x1a0/0x1a0 [ 81.545749] kthread+0x112/0x130 [ 81.546358] ? kthread_flush_work_fn+0x10/0x10 [ 81.547183] ret_from_fork+0x22/0x40 [ 81.547842] ---[ end trace aa97649bd16c8655 ]--- [ 83.546539] general protection fault: 0000 [#1] SMP NOPTI [ 83.547422] CPU: 5 PID: 3225 Comm: modprobe Kdump: loaded Tainted: G W --------- - - 4.18.0-167.el8.x86_64 #1 [ 83.549191] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 83.550544] RIP: 0010:__pv_queued_spin_lock_slowpath+0x19a/0x2a0 [ 83.551504] Code: c4 c1 ea 12 41 be 01 00 00 00 4c 8d 6d 14 41 83 e4 03 8d 42 ff 49 c1 e4 05 48 98 49 81 c4 40 a5 02 00 4c 03 24 c5 60 48 34 91 <49> 89 2c 24 b8 00 80 00 00 eb 15 84 c0 75 0a 41 0f b6 54 24 14 84 [ 83.554449] RSP: 0018:ffffb51a0323fdb0 EFLAGS: 00010202 [ 83.555290] RAX: 000000000000301c RBX: ffffffff92080020 RCX: 0000000000000001 [ 83.556426] RDX: 000000000000301d RSI: 0000000000000000 RDI: 0000000000000000 [ 83.557556] RBP: ffff9e66f196a540 R08: 000000000000028a R09: ffff9e66d2757788 [ 83.558688] R10: 0000000000000000 R11: 0000000000000000 R12: 646e61725f770b07 [ 83.559821] R13: ffff9e66f196a554 R14: 0000000000000001 R15: 0000000000180000 [ 83.560958] FS: 00007fd5032e8740(0000) GS:ffff9e66f1940000(0000) knlGS:0000000000000000 [ 83.562233] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 83.563149] CR2: 00007fd5022b0da0 CR3: 000000038c334000 CR4: 00000000003406e0 Signed-off-by: Andrew Melnychenko Cc: stable Link: https://lore.kernel.org/r/20200414191503.3471783-1-andrew@daynix.com Signed-off-by: Greg Kroah-Hartman

tty: hvcs: Fix odd use of strlcpy

2019-09-04T10:43:44+00:00

Use the typical style of array, not the equivalent &array[0]. Signed-off-by: Joe Perches Link: https://lore.kernel.org/r/1be432798311378947ec4e6051cad1235b6eccbb.1562283944.git.joe@perches.com Signed-off-by: Greg Kroah-Hartman

docs: powerpc: convert docs to ReST and rename to *.rst

2019-07-17T09:57:51+00:00

Convert docs to ReST and add them to the arch-specific book. The conversion here was trivial, as almost every file there was already using an elegant format close to ReST standard. The changes were mostly to mark literal blocks and add a few missing section title identifiers. One note with regards to "--": on Sphinx, this can't be used to identify a list, as it will format it badly. This can be used, however, to identify a long hyphen - and "---" is an even longer one. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab Acked-by: Andrew Donnellan # cxl

powerpc/pseries/hvconsole: Fix stack overread via udbg

2019-06-14T05:35:53+00:00

While developing KASAN for 64-bit book3s, I hit the following stack over-read. It occurs because the hypercall to put characters onto the terminal takes 2 longs (128 bits/16 bytes) of characters at a time, and so hvc_put_chars() would unconditionally copy 16 bytes from the argument buffer, regardless of supplied length. However, udbg_hvc_putc() can call hvc_put_chars() with a single-byte buffer, leading to the error. ================================================================== BUG: KASAN: stack-out-of-bounds in hvc_put_chars+0xdc/0x110 Read of size 8 at addr c0000000023e7a90 by task swapper/0 CPU: 0 PID: 0 Comm: swapper Not tainted 5.2.0-rc2-next-20190528-02824-g048a6ab4835b #113 Call Trace: dump_stack+0x104/0x154 (unreliable) print_address_description+0xa0/0x30c __kasan_report+0x20c/0x224 kasan_report+0x18/0x30 __asan_report_load8_noabort+0x24/0x40 hvc_put_chars+0xdc/0x110 hvterm_raw_put_chars+0x9c/0x110 udbg_hvc_putc+0x154/0x200 udbg_write+0xf0/0x240 console_unlock+0x868/0xd30 register_console+0x970/0xe90 register_early_udbg_console+0xf8/0x114 setup_arch+0x108/0x790 start_kernel+0x104/0x784 start_here_common+0x1c/0x534 Memory state around the buggy address: c0000000023e7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0000000023e7a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 >c0000000023e7a80: f1 f1 01 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 ^ c0000000023e7b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c0000000023e7b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ================================================================== Document that a 16-byte buffer is requred, and provide it in udbg. Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

Merge tag 'riscv-for-linus-5.2-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux

2019-05-19T16:56:36+00:00

Pull RISC-V updates from Palmer Dabbelt: "This contains an assortment of RISC-V related patches that I'd like to target for the 5.2 merge window. Most of the patches are cleanups, but there are a handful of user-visible changes: - The nosmp and nr_cpus command-line arguments are now supported, which work like normal. - The SBI console no longer installs itself as a preferred console, we rely on standard mechanisms (/chosen, command-line, hueristics) instead. - sfence_remove_sfence_vma{,_asid} now pass their arguments along to the SBI call. - Modules now support BUG(). - A missing sfence.vma during boot has been added. This bug only manifests during boot. - The arch/riscv support for SiFive's L2 cache controller has been merged, which should un-block the EDAC framework work. I've only tested this on QEMU again, as I didn't have time to get things running on the Unleashed. The latest master from this morning merges in cleanly and passes the tests as well" * tag 'riscv-for-linus-5.2-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux: (31 commits) riscv: fix locking violation in page fault handler RISC-V: sifive_l2_cache: Add L2 cache controller driver for SiFive SoCs RISC-V: Add DT documentation for SiFive L2 Cache Controller RISC-V: Avoid using invalid intermediate translations riscv: Support BUG() in kernel module riscv: Add the support for c.ebreak check in is_valid_bugaddr() riscv: support trap-based WARN() riscv: fix sbi_remote_sfence_vma{,_asid}. riscv: move switch_mm to its own file riscv: move flush_icache_{all,mm} to cacheflush.c tty: Don't force RISCV SBI console as preferred console RISC-V: Access CSRs using CSR numbers RISC-V: Add interrupt related SCAUSE defines in asm/csr.h RISC-V: Use tabs to align macro values in asm/csr.h RISC-V: Fix minor checkpatch issues. RISC-V: Support nr_cpus command line option. RISC-V: Implement nosmp commandline option. RISC-V: Add RISC-V specific arch_match_cpu_phys_id riscv: vdso: drop unnecessary cc-ldoption riscv: call pm_power_off from machine_halt / machine_power_off ...

tty: Don't force RISCV SBI console as preferred console

2019-05-17T03:42:11+00:00

The Linux kernel will auto-disables all boot consoles whenever it gets a preferred real console. Currently on RISC-V systems, if we have a real console which is not RISCV SBI console then boot consoles (such as earlycon=sbi) are not auto-disabled when a real console (ttyS0 or ttySIF0) is available. This results in duplicate prints at boot-time after kernel starts using real console (i.e. ttyS0 or ttySIF0) if "earlycon=" kernel parameter was passed by bootloader. The reason for above issue is that RISCV SBI console always adds itself as preferred console which is causing other real consoles to be not used as preferred console. Ideally "console=" kernel parameter passed by bootloaders should be the one selecting a preferred real console. This patch fixes above issue by not forcing RISCV SBI console as preferred console. Fixes: afa6b1ccfad5 ("tty: New RISC-V SBI console driver") Cc: stable@vger.kernel.org Signed-off-by: Anup Patel Reviewed-by: Atish Patra Signed-off-by: Palmer Dabbelt