INFO: task hung in n_tty_read
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syzbot
Jan 16, 2020, 3:19:12 PM1/16/20
to syzkaller...@googlegroups.com
Hello,
syzbot found the following crash on:
HEAD commit: c04fc6fa Linux 4.14.165
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14510b71e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d36f53294bbc71f0
dashboard link: https://syzkaller.appspot.com/bug?extid=30e3069f026f890be1b6
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+30e306...@syzkaller.appspotmail.com
audit: type=1400 audit(1579205821.669:646): avc: denied { map } for
pid=15595 comm="sh" path="/bin/dash" dev="sda1" ino=1473
scontext=system_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
INFO: task getty:7319 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
getty D25920 7319 1 0x00000000
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_timeout+0x93b/0xe10 kernel/time/timer.c:1723
do_wait_for_common kernel/sched/completion.c:91 [inline]
__wait_for_common kernel/sched/completion.c:112 [inline]
wait_for_common kernel/sched/completion.c:123 [inline]
wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
flush_work+0x3eb/0x730 kernel/workqueue.c:2891
tty_buffer_flush_work+0x16/0x20 drivers/tty/tty_buffer.c:612
n_tty_read+0x813/0x17d0 drivers/tty/n_tty.c:2199
tty_read+0x171/0x270 drivers/tty/tty_io.c:866
__vfs_read+0x105/0x6a0 fs/read_write.c:411
vfs_read+0x137/0x350 fs/read_write.c:447
SYSC_read fs/read_write.c:574 [inline]
SyS_read+0xfd/0x230 fs/read_write.c:567
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fd5a864d310
RSP: 002b:00007ffe81d37648 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd5a8d226a8 RCX: 00007fd5a864d310
RDX: 0000000000000001 RSI: 00007ffe81d37698 RDI: 0000000000000000
RBP: 00007ffe81d37e80 R08: 0000000000000000 R09: 00007fd5a8903e90
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006075a0
R13: 00007ffe81d3aeda R14: 0000000000000000 R15: 0000000000000000
INFO: task kworker/u4:3:4751 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:3 D26144 4751 2 0x80000000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
INFO: task syz-executor.0:15571 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D29328 15571 7367 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
tty_buffer_lock_exclusive+0x1f/0x30 drivers/tty/tty_buffer.c:60
paste_selection+0x106/0x3f2 drivers/tty/vt/selection.c:349
tioclinux+0x10e/0x400 drivers/tty/vt/vt.c:2696
vt_ioctl+0x180c/0x2170 drivers/tty/vt/vt_ioctl.c:364
tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45aff9
RSP: 002b:00007f82861f5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f82861f66d4 RCX: 000000000045aff9
RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000054d R14: 00000000004c653e R15: 000000000075bf2c
Showing all locks held in the system:
1 lock held by khungtaskd/1053:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81489c18>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
2 locks held by getty/7319:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7320:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7321:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7322:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7323:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7324:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7325:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
3 locks held by kworker/u4:3/4751:
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>] work_static
include/linux/workqueue.h:199 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>] set_work_data
kernel/workqueue.c:619 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>]
set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>]
process_one_work+0x76e/0x1600 kernel/workqueue.c:2085
#1: ((&buf->work)){+.+.}, at: [<ffffffff813d319b>]
process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089
#2: (&buf->lock){+.+.}, at: [<ffffffff834d9499>]
flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499
2 locks held by syz-executor.0/15571:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&buf->lock){+.+.}, at: [<ffffffff834d8b5f>]
tty_buffer_lock_exclusive+0x1f/0x30 drivers/tty/tty_buffer.c:60
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1053 Comm: khungtaskd Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 29785 Comm: kworker/u4:4 Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: bat_events batadv_purge_orig
task: ffff8880807fe100 task.stack: ffff888053ec8000
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:796 [inline]
RIP: 0010:lock_release+0xc5/0x940 kernel/locking/lockdep.c:4009
RSP: 0018:ffff888053ecfbc8 EFLAGS: 00000286
RAX: 0000000000000286 RBX: 1ffff1100a7d9f7f RCX: 00000000c79f1bf8
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880807fe97c
RBP: ffff888053ecfc60 R08: 00000000000029d2 R09: ffffffff8957f850
R10: 0000000000000000 R11: ffff8880807fe100 R12: ffff888062dc10a8
R13: ffffffff86520c00 R14: ffff8880807fe100 R15: ffff888053ecfc38
FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42cef9530 CR3: 000000009a0e5000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline]
_raw_spin_unlock_bh+0x1b/0x40 kernel/locking/spinlock.c:208
spin_unlock_bh include/linux/spinlock.h:362 [inline]
_batadv_purge_orig+0xa90/0xfb0 net/batman-adv/originator.c:1325
batadv_purge_orig+0x1b/0x70 net/batman-adv/originator.c:1338
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 69 f1 87 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85
cb 06 00 00 48 83 3d f3 fb a8 06 00 0f 84 3f 05 00 00 9c 58 <0f> 1f 44 00
00 48 ba 00 00 00 00 00 fc ff df 48 89 45 88 48 c7
---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.
syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot found the following crash on:
HEAD commit: c04fc6fa Linux 4.14.165
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14510b71e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d36f53294bbc71f0
dashboard link: https://syzkaller.appspot.com/bug?extid=30e3069f026f890be1b6
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+30e306...@syzkaller.appspotmail.com
audit: type=1400 audit(1579205821.669:646): avc: denied { map } for
pid=15595 comm="sh" path="/bin/dash" dev="sda1" ino=1473
scontext=system_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1
INFO: task getty:7319 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
getty D25920 7319 1 0x00000000
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_timeout+0x93b/0xe10 kernel/time/timer.c:1723
do_wait_for_common kernel/sched/completion.c:91 [inline]
__wait_for_common kernel/sched/completion.c:112 [inline]
wait_for_common kernel/sched/completion.c:123 [inline]
wait_for_completion+0x27c/0x420 kernel/sched/completion.c:144
flush_work+0x3eb/0x730 kernel/workqueue.c:2891
tty_buffer_flush_work+0x16/0x20 drivers/tty/tty_buffer.c:612
n_tty_read+0x813/0x17d0 drivers/tty/n_tty.c:2199
tty_read+0x171/0x270 drivers/tty/tty_io.c:866
__vfs_read+0x105/0x6a0 fs/read_write.c:411
vfs_read+0x137/0x350 fs/read_write.c:447
SYSC_read fs/read_write.c:574 [inline]
SyS_read+0xfd/0x230 fs/read_write.c:567
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7fd5a864d310
RSP: 002b:00007ffe81d37648 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007fd5a8d226a8 RCX: 00007fd5a864d310
RDX: 0000000000000001 RSI: 00007ffe81d37698 RDI: 0000000000000000
RBP: 00007ffe81d37e80 R08: 0000000000000000 R09: 00007fd5a8903e90
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006075a0
R13: 00007ffe81d3aeda R14: 0000000000000000 R15: 0000000000000000
INFO: task kworker/u4:3:4751 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:3 D26144 4751 2 0x80000000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
INFO: task syz-executor.0:15571 blocked for more than 140 seconds.
Not tainted 4.14.165-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.0 D29328 15571 7367 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3486
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0x73c/0x1470 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
tty_buffer_lock_exclusive+0x1f/0x30 drivers/tty/tty_buffer.c:60
paste_selection+0x106/0x3f2 drivers/tty/vt/selection.c:349
tioclinux+0x10e/0x400 drivers/tty/vt/vt.c:2696
vt_ioctl+0x180c/0x2170 drivers/tty/vt/vt_ioctl.c:364
tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45aff9
RSP: 002b:00007f82861f5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f82861f66d4 RCX: 000000000045aff9
RDX: 0000000020000000 RSI: 000000000000541c RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000054d R14: 00000000004c653e R15: 000000000075bf2c
Showing all locks held in the system:
1 lock held by khungtaskd/1053:
#0: (tasklist_lock){.+.+}, at: [<ffffffff81489c18>]
debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4544
2 locks held by getty/7319:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7320:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7321:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7322:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7323:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7324:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
2 locks held by getty/7325:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff834ca396>]
n_tty_read+0x1e6/0x17d0 drivers/tty/n_tty.c:2156
3 locks held by kworker/u4:3/4751:
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>] work_static
include/linux/workqueue.h:199 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>] set_work_data
kernel/workqueue.c:619 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>]
set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline]
#0: ("events_unbound"){+.+.}, at: [<ffffffff813d315e>]
process_one_work+0x76e/0x1600 kernel/workqueue.c:2085
#1: ((&buf->work)){+.+.}, at: [<ffffffff813d319b>]
process_one_work+0x7ab/0x1600 kernel/workqueue.c:2089
#2: (&buf->lock){+.+.}, at: [<ffffffff834d9499>]
flush_to_ldisc+0x39/0x400 drivers/tty/tty_buffer.c:499
2 locks held by syz-executor.0/15571:
#0: (&tty->ldisc_sem){++++}, at: [<ffffffff866a6243>]
ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376
#1: (&buf->lock){+.+.}, at: [<ffffffff834d8b5f>]
tty_buffer_lock_exclusive+0x1f/0x30 drivers/tty/tty_buffer.c:60
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1053 Comm: khungtaskd Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
watchdog+0x5e7/0xb90 kernel/hung_task.c:274
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 29785 Comm: kworker/u4:4 Not tainted 4.14.165-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: bat_events batadv_purge_orig
task: ffff8880807fe100 task.stack: ffff888053ec8000
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:774 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:796 [inline]
RIP: 0010:lock_release+0xc5/0x940 kernel/locking/lockdep.c:4009
RSP: 0018:ffff888053ecfbc8 EFLAGS: 00000286
RAX: 0000000000000286 RBX: 1ffff1100a7d9f7f RCX: 00000000c79f1bf8
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff8880807fe97c
RBP: ffff888053ecfc60 R08: 00000000000029d2 R09: ffffffff8957f850
R10: 0000000000000000 R11: ffff8880807fe100 R12: ffff888062dc10a8
R13: ffffffff86520c00 R14: ffff8880807fe100 R15: ffff888053ecfc38
FS: 0000000000000000(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42cef9530 CR3: 000000009a0e5000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline]
_raw_spin_unlock_bh+0x1b/0x40 kernel/locking/spinlock.c:208
spin_unlock_bh include/linux/spinlock.h:362 [inline]
_batadv_purge_orig+0xa90/0xfb0 net/batman-adv/originator.c:1325
batadv_purge_orig+0x1b/0x70 net/batman-adv/originator.c:1338
process_one_work+0x863/0x1600 kernel/workqueue.c:2114
worker_thread+0x5d9/0x1050 kernel/workqueue.c:2248
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Code: 69 f1 87 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85
cb 06 00 00 48 83 3d f3 fb a8 06 00 0f 84 3f 05 00 00 9c 58 <0f> 1f 44 00
00 48 ba 00 00 00 00 00 fc ff df 48 89 45 88 48 c7
---
This bug is generated by a bot. It may contain errors.
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syzbot
Jun 24, 2020, 11:18:09 PM6/24/20
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Crashes did not happen for a while, no reproducer and no activity.
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