syzbot


INFO: task hung in __do_page_fault

Status: fixed on 2018/05/17 10:02
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+ed2546e8398d45abf658@syzkaller.appspotmail.com
Fix commit: 8236b0ae31c8 bdi: wake up concurrent wb_shutdown() callers.
First crash: 2291d, last: 2291d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-44 INFO: task hung in __do_page_fault C 1 1985d 1927d 0/2 public: reported C repro on 2019/04/14 00:00
linux-4.14 INFO: task hung in __do_page_fault C error 16 585d 1922d 0/1 upstream: reported C repro on 2019/04/19 08:53
upstream INFO: task hung in __do_page_fault (2) C done error 34 1812d 2096d 0/27 closed as invalid on 2022/02/08 10:55
android-49 INFO: task hung in __do_page_fault C 5 1753d 1927d 0/3 public: reported C repro on 2019/04/14 08:51
linux-4.19 INFO: task hung in __do_page_fault gfs2 C error 31 567d 1872d 0/1 upstream: reported C repro on 2019/06/08 06:01
android-414 INFO: task hung in __do_page_fault C 7 1762d 1929d 0/1 public: reported C repro on 2019/04/12 00:01

Sample crash report:
CPU: 0 PID: 17444 Comm: syz-executor1 Not tainted 4.16.0+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 handle_userfault.cold.32+0x44/0x57 fs/userfaultfd.c:430
INFO: task kworker/0:0:30523 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:0     D
 do_anonymous_page mm/memory.c:3147 [inline]
 handle_pte_fault mm/memory.c:3961 [inline]
 __handle_mm_fault+0x34be/0x4150 mm/memory.c:4087
23360 30523      2 0x80000000
Workqueue: events cgwb_release_workfn
 handle_mm_fault+0x53a/0xc70 mm/memory.c:4124
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x801/0x1e30 kernel/sched/core.c:3490
 __do_page_fault+0x60b/0xe40 arch/x86/mm/fault.c:1399
 do_page_fault+0xee/0x8a7 arch/x86/mm/fault.c:1474
 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1159
RIP: 0010:copy_user_generic_unrolled+0x86/0xc0 arch/x86/lib/copy_user_64.S:65
RSP: 0018:ffff8801b57ffce8 EFLAGS: 00010206
RAX: ffffed0036afffae RBX: 0000000000000018 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000020013000 RDI: ffff8801b57ffd58
RBP: ffff8801b57ffd20 R08: ffffed0036afffae R09: ffffed0036afffab
R10: ffffed0036afffad R11: ffff8801b57ffd6f R12: 0000000020013018
R13: 0000000020013000 R14: ffff8801b57ffd58 R15: 00007ffffffff000
 copy_from_user include/linux/uaccess.h:147 [inline]
 SYSC_sigaltstack kernel/signal.c:3539 [inline]
 SyS_sigaltstack+0xae/0x320 kernel/signal.c:3535
 schedule+0xef/0x430 kernel/sched/core.c:3549
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455319
RSP: 002b:00007fe24ecf0c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000083
RAX: ffffffffffffffda RBX: 00007fe24ecf16d4 RCX: 0000000000455319
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020013000
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000609 R14: 00000000006fc178 R15: 0000000000000000
FAULT_FLAG_ALLOW_RETRY missing 30
 bit_wait+0x18/0x90 kernel/sched/wait_bit.c:197
 __wait_on_bit+0xb3/0x130 kernel/sched/wait_bit.c:48
CPU: 0 PID: 17497 Comm: syz-executor1 Not tainted 4.16.0+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:63
 handle_userfault.cold.32+0x44/0x57 fs/userfaultfd.c:430
 wait_on_bit include/linux/wait_bit.h:76 [inline]
 wb_shutdown+0x370/0x470 mm/backing-dev.c:366
 do_anonymous_page mm/memory.c:3147 [inline]
 handle_pte_fault mm/memory.c:3961 [inline]
 __handle_mm_fault+0x34be/0x4150 mm/memory.c:4087
 cgwb_release_workfn+0x87/0x750 mm/backing-dev.c:509
 handle_mm_fault+0x53a/0xc70 mm/memory.c:4124
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 __do_page_fault+0x60b/0xe40 arch/x86/mm/fault.c:1399
 do_page_fault+0xee/0x8a7 arch/x86/mm/fault.c:1474
 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1159
RIP: 0010:copy_user_generic_unrolled+0x86/0xc0 arch/x86/lib/copy_user_64.S:65
RSP: 0018:ffff8801b7947ce8 EFLAGS: 00010206
RAX: ffffed0036f28fae RBX: 0000000000000018 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000020013000 RDI: ffff8801b7947d58
RBP: ffff8801b7947d20 R08: ffffed0036f28fae R09: ffffed0036f28fab
R10: ffffed0036f28fad R11: ffff8801b7947d6f R12: 0000000020013018
R13: 0000000020013000 R14: ffff8801b7947d58 R15: 00007ffffffff000
 copy_from_user include/linux/uaccess.h:147 [inline]
 SYSC_sigaltstack kernel/signal.c:3539 [inline]
 SyS_sigaltstack+0xae/0x320 kernel/signal.c:3535
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x455319
RSP: 002b:00007fe24eccfc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000083
RAX: ffffffffffffffda RBX: 00007fe24ecd06d4 RCX: 0000000000455319
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 0000000020013000
RBP: 000000000072bf58 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000609 R14: 00000000006fc178 R15: 0000000000000001
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

Showing all locks held in the system:
2 locks held by khungtaskd/888:
 #0: 00000000b28f14ec (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0: 00000000b28f14ec (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249
 #1: 00000000d6bbe5a4 (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470
2 locks held by getty/4460:
 #0: 00000000e22884b3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000013ddc9b8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4461:
 #0: 000000005f04ec02 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000005d4f8527 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4462:
 #0: 000000003405dd15 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000c3ec63c1 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4463:
 #0: 00000000ec641df5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000058ea1741 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4464:
 #0: 00000000f097c053 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000c124b7ae (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4465:
 #0: 00000000f89440e2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000f6071068 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by kworker/0:0/30523:
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000ffece5e8 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116
 #1: 00000000fdef1b4a ((work_completion)(&wb->release_work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120
2 locks held by getty/12970:
 #0: 000000001b7411ee (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000008730ecb6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131

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

NMI backtrace for cpu 1
CPU: 1 PID: 888 Comm: khungtaskd Not tainted 4.16.0+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 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:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0xc10/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/15 16:21 upstream 18b7fd1c93e5 7a67784c .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.