bisecting fixing commit since 7ae77150d94d3b535c7b85e6b3647113095e79bf
building syzkaller on e6b89e4e5adde15c0dc0a241e03dc215f2e249b3
testing commit 7ae77150d94d3b535c7b85e6b3647113095e79bf with gcc (GCC) 8.1.0
kernel signature: 650dc65ce4b040dc1430839396b913a7fd8d42bc97d24d4ca485f23f10fed2d1
run #0: crashed: INFO: task hung in pipe_write
run #1: crashed: INFO: task hung in pipe_write
run #2: crashed: INFO: task hung in pipe_write
run #3: crashed: INFO: task hung in pipe_write
run #4: crashed: INFO: task hung in pipe_read
run #5: crashed: INFO: task hung in pipe_read
run #6: crashed: INFO: task hung in pipe_write
run #7: crashed: INFO: task hung in pipe_write
run #8: crashed: INFO: task hung in pipe_write
run #9: crashed: INFO: task hung in pipe_write
testing current HEAD 7575fdda569b2a2e8be32c1a64ecb05d6f96a500
testing commit 7575fdda569b2a2e8be32c1a64ecb05d6f96a500 with gcc (GCC) 8.1.0
kernel signature: cbe598ee76d7a744bd899c16240b332807fcda1e9321d9c4d6e33902d2ebfcac
run #0: crashed: INFO: task hung in pipe_read
run #1: crashed: INFO: task hung in pipe_write
run #2: crashed: INFO: task hung in pipe_write
run #3: crashed: INFO: task hung in pipe_write
run #4: crashed: INFO: task hung in pipe_write
run #5: crashed: INFO: task hung in pipe_write
run #6: crashed: INFO: task hung in pipe_write
run #7: crashed: INFO: task hung in pipe_write
run #8: crashed: INFO: task hung in pipe_read
run #9: crashed: INFO: task hung in pipe_write
revisions tested: 2, total time: 28m38.182955231s (build: 11m8.18553552s, test: 16m53.292621511s)
the crash still happens on HEAD
commit msg: Merge tag 'platform-drivers-x86-v5.9-2' of git://git.infradead.org/linux-platform-drivers-x86
crash: INFO: task hung in pipe_write
INFO: task syz-executor.1:29164 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:14816 pid:29164 ppid:  6902 flags:0x00000000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x404/0x8a0 kernel/sched/core.c:4527
 schedule+0x37/0xe0 kernel/sched/core.c:4602
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103
 __pipe_lock fs/pipe.c:87 [inline]
 pipe_write+0x47/0x600 fs/pipe.c:416
 call_write_iter include/linux/fs.h:1882 [inline]
 new_sync_write+0x18a/0x1a0 fs/read_write.c:503
 vfs_write+0x19b/0x230 fs/read_write.c:586
 ksys_write+0xb9/0xd0 fs/read_write.c:639
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cae9
Code: Bad RIP value.
RSP: 002b:00007f802c864c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050ca00 RCX: 000000000045cae9
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf454 R15: 00007f802c8656d4
INFO: task syz-executor.1:29473 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:14872 pid:29473 ppid:  6902 flags:0x00000000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x404/0x8a0 kernel/sched/core.c:4527
 schedule+0x37/0xe0 kernel/sched/core.c:4602
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103
 __pipe_lock fs/pipe.c:87 [inline]
 pipe_write+0x47/0x600 fs/pipe.c:416
 call_write_iter include/linux/fs.h:1882 [inline]
 new_sync_write+0x18a/0x1a0 fs/read_write.c:503
 vfs_write+0x19b/0x230 fs/read_write.c:586
 ksys_write+0xb9/0xd0 fs/read_write.c:639
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cae9
Code: Bad RIP value.
RSP: 002b:00007f802c864c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050ca00 RCX: 000000000045cae9
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf454 R15: 00007f802c8656d4
INFO: task syz-executor.1:29598 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:14872 pid:29598 ppid:  6902 flags:0x00000000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x404/0x8a0 kernel/sched/core.c:4527
 schedule+0x37/0xe0 kernel/sched/core.c:4602
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103
 __pipe_lock fs/pipe.c:87 [inline]
 pipe_write+0x47/0x600 fs/pipe.c:416
 call_write_iter include/linux/fs.h:1882 [inline]
 new_sync_write+0x18a/0x1a0 fs/read_write.c:503
 vfs_write+0x19b/0x230 fs/read_write.c:586
 ksys_write+0xb9/0xd0 fs/read_write.c:639
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cae9
Code: Bad RIP value.
RSP: 002b:00007f802c864c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050ca00 RCX: 000000000045cae9
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf454 R15: 00007f802c8656d4
INFO: task syz-executor.1:29672 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc8-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:14872 pid:29672 ppid:  6902 flags:0x00000000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x404/0x8a0 kernel/sched/core.c:4527
 schedule+0x37/0xe0 kernel/sched/core.c:4602
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x472/0x9f0 kernel/locking/mutex.c:1103
 __pipe_lock fs/pipe.c:87 [inline]
 pipe_write+0x47/0x600 fs/pipe.c:416
 call_write_iter include/linux/fs.h:1882 [inline]
 new_sync_write+0x18a/0x1a0 fs/read_write.c:503
 vfs_write+0x19b/0x230 fs/read_write.c:586
 ksys_write+0xb9/0xd0 fs/read_write.c:639
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cae9
Code: Bad RIP value.
RSP: 002b:00007f802c864c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050ca00 RCX: 000000000045cae9
RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000000
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000cec R14: 00000000004cf454 R15: 00007f802c8656d4
INFO: task syz-executor.1:29711 blocked for more than 144 seconds.