syzbot


INFO: task hung in pipe_read

Status: upstream: reported syz repro on 2019/12/19 13:28
Reported-by: syzbot+d8a024467aae529327f3@syzkaller.appspotmail.com
First crash: 965d, last: 795d

Fix bisection: the fix commit could be any of (bisect log):
  c6db52a88798 Linux 4.14.183
  4139fb08c05f Linux 4.14.187
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in pipe_read (2) syz 1 739d 739d 0/23 closed as dup on 2020/08/01 15:30
upstream INFO: task hung in pipe_read 2 1363d 1401d 0/23 auto-closed as invalid on 2019/05/15 12:28

Sample crash report:
INFO: task syz-execprog:6342 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-execprog    D28416  6342   6334 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 pipe_lock_nested fs/pipe.c:67 [inline]
 pipe_lock fs/pipe.c:75 [inline]
 pipe_wait+0x171/0x190 fs/pipe.c:123
 pipe_read+0x4e3/0x850 fs/pipe.c:352
 call_read_iter include/linux/fs.h:1772 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x44b/0x610 fs/read_write.c:413
 vfs_read+0x131/0x330 fs/read_write.c:447
 SYSC_read fs/read_write.c:574 [inline]
 SyS_read+0xf2/0x210 fs/read_write.c:567
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x4ad7db
RSP: 002b:000000c000473610 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000000c000020800 RCX: 00000000004ad7db
RDX: 0000000000010000 RSI: 000000c000294000 RDI: 000000000000000c
RBP: 000000c000473660 R08: 0000000000000001 R09: 0000000000000002
R10: 000000c000284000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000001 R14: 000000c0003375c0 R15: 0000000000000000
INFO: task syz-execprog:6343 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-execprog    D28016  6343   6334 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_read+0xba/0x850 fs/pipe.c:279
 call_read_iter include/linux/fs.h:1772 [inline]
 new_sync_read fs/read_write.c:401 [inline]
 __vfs_read+0x44b/0x610 fs/read_write.c:413
 vfs_read+0x131/0x330 fs/read_write.c:447
 SYSC_read fs/read_write.c:574 [inline]
 SyS_read+0xf2/0x210 fs/read_write.c:567
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x4ad7db
RSP: 002b:000000c000470e10 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 000000c00001e000 RCX: 00000000004ad7db
RDX: 0000000000010000 RSI: 000000c000254000 RDI: 0000000000000026
RBP: 000000c000470e60 R08: 0000000000000001 R09: 0000000000000002
R10: 000000c000244000 R11: 0000000000000202 R12: 0000000000000003
R13: 000000c000000f00 R14: 000000c000057c80 R15: 0000000000000000
INFO: task syz-executor.2:11982 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D30336 11982   6358 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffd32845368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000014c5914
INFO: task syz-executor.3:12616 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D30336 12616   6364 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffc2bf6bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000023e6914
INFO: task syz-executor.3:12655 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D30656 12655   6364 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffc2bf6bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000023e6914
INFO: task syz-executor.3:12879 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D30336 12879   6364 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffc2bf6bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000023e6914
INFO: task syz-executor.2:12945 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D30336 12945   6358 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffd32845368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000014c5914
INFO: task syz-executor.3:13109 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.3  D30336 13109   6364 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffc2bf6bf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000023e6914
INFO: task syz-executor.2:13181 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D30336 13181   6358 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffd32845368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000014c5914
INFO: task syz-executor.2:13185 blocked for more than 140 seconds.
      Not tainted 4.14.183-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D30336 13185   6358 0x00000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486
 __mutex_lock_common kernel/locking/mutex.c:833 [inline]
 __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893
 __pipe_lock fs/pipe.c:88 [inline]
 pipe_write+0xb7/0xe10 fs/pipe.c:385
 call_write_iter include/linux/fs.h:1778 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x44e/0x630 fs/read_write.c:482
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007ffd32845368 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c980 RCX: 000000000045ca69
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf3d4 R15: 00000000014c5914

Showing all locks held in the system:
1 lock held by khungtaskd/1048:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8146c8d0>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
1 lock held by in:imklog/6001:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff8191e426>] __fdget_pos+0xa6/0xc0 fs/file.c:769
1 lock held by syz-execprog/6342:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock_nested fs/pipe.c:67 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock fs/pipe.c:75 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_wait+0x171/0x190 fs/pipe.c:123
1 lock held by syz-execprog/6343:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4f4a>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4f4a>] pipe_read+0xba/0x850 fs/pipe.c:279
1 lock held by syz-executor.2/11805:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock_nested fs/pipe.c:67 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock fs/pipe.c:75 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_wait+0x171/0x190 fs/pipe.c:123
1 lock held by syz-executor.2/11982:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/12560:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock_nested fs/pipe.c:67 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_lock fs/pipe.c:75 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d3f21>] pipe_wait+0x171/0x190 fs/pipe.c:123
1 lock held by syz-executor.3/12616:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/12655:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/12879:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/12945:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13109:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13181:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13185:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13411:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13510:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13558:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13565:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13573:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13574:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13579:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13799:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/13803:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13822:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/13925:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14015:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14064:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14066:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14083:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14093:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14163:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14192:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14268:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14460:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14492:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14494:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/14655:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/14825:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15032:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15064:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/15086:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15169:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15210:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15254:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15260:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/15345:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/15689:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15785:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/15988:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.2/16113:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
1 lock held by syz-executor.3/16176:
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] __pipe_lock fs/pipe.c:88 [inline]
 #0:  (&pipe->mutex/1){+.+.}, at: [<ffffffff818d4137>] pipe_write+0xb7/0xe10 fs/pipe.c:385
2 locks held by syz-executor.4/16423:
 #0:  (sb_writers#3){.+.+}, at: [<ffffffff818bc2e8>] file_start_write include/linux/fs.h:2708 [inline]
 #0:  (sb_writers#3){.+.+}, at: [<ffffffff818bc2e8>] vfs_write+0x3d8/0x4d0 fs/read_write.c:543
 #1:  (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bb7cad>] inode_trylock include/linux/fs.h:739 [inline]
 #1:  (&sb->s_type->i_mutex_key#9){+.+.}, at: [<ffffffff81bb7cad>] ext4_file_write_iter+0x1cd/0xd90 fs/ext4/file.c:236

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1048 Comm: khungtaskd Not tainted 4.14.183-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+0x1b2/0x283 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e2/0xb80 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 6358 Comm: syz-executor.2 Not tainted 4.14.183-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809c1745c0 task.stack: ffff88809a248000
RIP: 0010:check_preemption_disabled+0xf/0x240 lib/smp_processor_id.c:13
RSP: 0018:ffff88809a24f8c0 EFLAGS: 00000297
RAX: ffff88809c1745c0 RBX: 0000000000000010 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff86c64880 RDI: ffffffff86c44760
RBP: ffffffff86c44760 R08: 0000000000000006 R09: fffffffffffffff4
R10: 000000000000000f R11: ffff88809c1745c0 R12: ffff8880a1faa3d8
R13: ffffffff86c64880 R14: ffffea0001ecb240 R15: ffff8880a1faa4b8
FS:  00000000014c5940(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f808d3847b8 CR3: 000000009ab0c000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 percpu_counter_add_batch+0x35/0x160 lib/percpu_counter.c:88
 __add_wb_stat include/linux/backing-dev.h:70 [inline]
 dec_wb_stat include/linux/backing-dev.h:80 [inline]
 account_page_cleaned mm/page-writeback.c:2462 [inline]
 account_page_cleaned+0x2e7/0x440 mm/page-writeback.c:2456
 cancel_dirty_page+0x343/0x4e0 mm/page-writeback.c:2643
 try_to_free_buffers+0x214/0x290 fs/buffer.c:3358
 ext4_releasepage+0x2ef/0x410 fs/ext4/inode.c:3421
 try_to_release_page+0x160/0x200 mm/filemap.c:3235
 block_invalidatepage+0x24e/0x2e0 fs/buffer.c:1573
 do_invalidatepage mm/truncate.c:124 [inline]
 truncate_complete_page mm/truncate.c:144 [inline]
 truncate_inode_page+0x20a/0x340 mm/truncate.c:192
 truncate_inode_pages_range+0x1cf/0x12c0 mm/truncate.c:316
 ext4_evict_inode+0x484/0x1500 fs/ext4/inode.c:248
 evict+0x2c8/0x5f0 fs/inode.c:555
 iput_final fs/inode.c:1524 [inline]
 iput fs/inode.c:1551 [inline]
 iput+0x457/0x8d0 fs/inode.c:1536
 do_unlinkat+0x35b/0x5c0 fs/namei.c:4098
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45c817
RSP: 002b:00007ffd328444b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045c817
RDX: 00007ffd328444d0 RSI: 00007ffd328444d0 RDI: 00007ffd32844560
RBP: 00000000000002c6 R08: 0000000000000000 R09: 0000000000000018
R10: 0000000000000012 R11: 0000000000000246 R12: 00007ffd328455f0
R13: 00000000014c6940 R14: 0000000000000000 R15: 00007ffd328455f0
Code: f6 f9 ff ff e8 23 80 85 fe e9 bf fd ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 49 89 f5 41 54 55 48 89 fd <53> e8 bb 46 5c fe 65 44 8b 25 03 22 03 7d 65 8b 05 9c 8e 03 7d 

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/06/07 04:23 linux-4.14.y c6db52a88798 e6b89e4e .config log report syz
ci2-linux-4-14 2019/12/19 13:27 linux-4.14.y bfb9e5c03076 79b211f7 .config log report syz