INFO: task hung in do_exit

Status: public: reported syz repro on 2019/04/13 00:01
Reported-by: syzbot+0b5b0db3e86b8fad4ed7@syzkaller.appspotmail.com
First crash: 2909d, last: 2455d
▶ ▼ Similar bugs (9)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_exit 1 syz done error 125 1665d 2687d 0/29 closed as invalid on 2022/02/08 10:54
linux-4.14 INFO: task hung in do_exit 1 syz inconclusive 8 1661d 2675d 0/1 upstream: reported syz repro on 2019/04/25 02:28
linux-6.1 INFO: task hung in do_exit (2) 1 1 239d 239d 0/3 auto-obsoleted due to no activity on 2026/04/04 10:17
linux-6.6 INFO: task hung in do_exit origin:lts-only 1 syz, C error 1 110d 110d 0/2 upstream: reported C repro on 2026/05/03 06:29
linux-4.19 INFO: task hung in do_exit 1 syz, C error 58 1293d 2681d 0/1 upstream: reported C repro on 2019/04/19 20:32
upstream INFO: task can't die in show_free_areas serial 1 syz, C error error 293 7h21m 1670d 0/29 upstream: reported C repro on 2022/01/24 13:23
android-6-12 INFO: task hung in do_exit 1 1 395d 395d 0/1 auto-obsoleted due to no activity on 2025/10/20 11:57
linux-6.1 INFO: task hung in do_exit 1 1 770d 770d 0/3 auto-obsoleted due to no activity on 2024/10/20 05:24
android-49 INFO: task hung in do_exit 1 syz 18 2502d 2686d 0/3 public: reported syz repro on 2019/04/14 09:28

Sample crash report:
INFO: task syz-executor.1:27798 blocked for more than 140 seconds.
      Not tainted 4.14.137+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D28624 27798   1955 0x80000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
 rwsem_down_read_failed+0x22a/0x3c0 kernel/locking/rwsem-xadd.c:309
 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:66 [inline]
 down_read+0x45/0xa0 kernel/locking/rwsem.c:26
 exit_mm kernel/exit.c:511 [inline]
 do_exit+0x575/0x2a20 kernel/exit.c:861
 do_group_exit+0x100/0x2e0 kernel/exit.c:977
 SYSC_exit_group kernel/exit.c:988 [inline]
 SyS_exit_group+0x19/0x20 kernel/exit.c:986
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007ffe1d2ba748 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 000000000000001e RCX: 0000000000459829
RDX: 0000000000413511 RSI: fffffffffffffff7 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffffffffffff R09: 00007ffe1d2ba7a0
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe1d2ba7a0 R14: 0000000000000000 R15: 00007ffe1d2ba7b0
INFO: task syz-executor.1:27801 blocked for more than 140 seconds.
      Not tainted 4.14.137+ #29
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.1  D28992 27801   1955 0x80000000
Call Trace:
 schedule+0x92/0x1c0 kernel/sched/core.c:3498
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:292 [inline]
 rwsem_down_read_failed+0x22a/0x3c0 kernel/locking/rwsem-xadd.c:309
 call_rwsem_down_read_failed+0x14/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:66 [inline]
 down_read+0x45/0xa0 kernel/locking/rwsem.c:26
 exit_mm kernel/exit.c:511 [inline]
 do_exit+0x575/0x2a20 kernel/exit.c:861
 do_group_exit+0x100/0x2e0 kernel/exit.c:977
 get_signal+0x39f/0x1cc0 kernel/signal.c:2409
 do_signal+0x96/0x15d0 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x11d/0x160 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x3a3/0x520 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007f84d257fcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000075bf28 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000075bf28
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000075bf2c
R13: 00007ffe1d2ba53f R14: 00007f84d25809c0 R15: 000000000075bf2c

Showing all locks held in the system:
1 lock held by khungtaskd/23:
 #0:  (tasklist_lock){.+.+}, at: [<        (ptrval)>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4541
2 locks held by getty/1783:
 #0:  (&tty->ldisc_sem){++++}, at: [<        (ptrval)>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<        (ptrval)>] n_tty_read+0x1f7/0x1700 drivers/tty/n_tty.c:2156
1 lock held by syz-executor.1/27798:
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] exit_mm kernel/exit.c:511 [inline]
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] do_exit+0x575/0x2a20 kernel/exit.c:861
1 lock held by syz-executor.1/27801:
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] exit_mm kernel/exit.c:511 [inline]
 #0:  (&mm->mmap_sem){++++}, at: [<        (ptrval)>] do_exit+0x575/0x2a20 kernel/exit.c:861

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

NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: khungtaskd Not tainted 4.14.137+ #29
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 nmi_cpu_backtrace.cold+0x47/0x86 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x119/0x147 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+0x629/0xbe0 kernel/hung_task.c:274
 kthread+0x31f/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 27813 Comm: syz-executor.1 Not tainted 4.14.137+ #29
task:         (ptrval) task.stack:         (ptrval)
RIP: 0010:get_lock_parent_ip include/linux/ftrace.h:738 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:3147 [inline]
RIP: 0010:preempt_count_add+0xb8/0x180 kernel/sched/core.c:3172
RSP: 0018:ffff8881c809fac0 EFLAGS: 00000297
RAX: 0000000000000000 RBX: ffffffffa068c442 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffffa068c442
RBP: ffff8881c809fad0 R08: ffffffff9f2098cd R09: ffffed103a5bdafd
R10: ffff8881c809fc68 R11: ffff8881d2ded7e7 R12: 0000000000000001
R13: ffff8881d2ded7e0 R14: 0000000000000000 R15: ffffffff9f2098cd
FS:  00007f84d255f700(0000) GS:ffff8881db900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f804926a330 CR3: 00000001c9a0c005 CR4: 00000000001606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __mutex_lock_common kernel/locking/mutex.c:755 [inline]
 __mutex_lock+0xd2/0x13e0 kernel/locking/mutex.c:893
 perf_mmap+0x50d/0x1480 kernel/events/core.c:5416
 call_mmap include/linux/fs.h:1793 [inline]
 mmap_region+0x7d9/0xfb0 mm/mmap.c:1732
 do_mmap+0x548/0xb80 mm/mmap.c:1510
 do_mmap_pgoff include/linux/mm.h:2209 [inline]
 vm_mmap_pgoff+0x177/0x1c0 mm/util.c:333
 SYSC_mmap_pgoff mm/mmap.c:1560 [inline]
 SyS_mmap_pgoff+0xf4/0x1b0 mm/mmap.c:1518
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x459829
RSP: 002b:00007f84d255ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000000003000 RDI: 0000000020ffd000
RBP: 000000000075bfc8 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000001011 R11: 0000000000000246 R12: 00007f84d255f6d4
R13: 00000000004c5d71 R14: 00000000004da748 R15: 00000000ffffffff
Code: b6 c0 3d f4 00 00 00 7f 66 65 8b 05 53 95 0b 61 25 ff ff ff 7f 41 39 c4 74 05 5b 41 5c 5d c3 48 8b 5d 08 48 89 df e8 d8 3c 0a 00 <85> c0 75 35 65 4c 8b 24 25 c0 de 01 00 49 8d bc 24 28 11 00 00

Crashes (19):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/08/07 08:51 android-4.14 b9cd593b1ba7 cdde7486 .config console log report syz ci-android-414-kasan-gce-root
2019/07/23 19:08 android-4.14 fae940268dce de453f34 .config console log report syz ci-android-414-kasan-gce-root
2019/06/27 03:33 android-4.14 93c338c2e7ba 7509bf36 .config console log report syz ci-android-414-kasan-gce-root
2019/06/17 13:01 android-4.14 cfee25d274dd 442206d7 .config console log report syz ci-android-414-kasan-gce-root
2019/06/08 09:31 android-4.14 76896566d7b9 cf9c3a50 .config console log report syz ci-android-414-kasan-gce-root
2019/04/21 17:47 android-4.14 fde41616bce4 b0e8efcb .config console log report syz ci-android-414-kasan-gce-root
2019/04/13 07:10 android-4.14 efe836537cf2 c402d8f1 .config console log report syz ci-android-414-kasan-gce-root
2018/09/22 02:43 android-4.14 666c420fa3ea 37079712 .config console log report syz ci-android-414-kasan-gce-root
2019/12/01 09:22 android-4.14 714ada7cabc7 a76bf83f .config console log report ci-android-414-kasan-gce-root
2019/11/05 21:18 android-4.14 6409e7e01d11 0f3ec414 .config console log report ci-android-414-kasan-gce-root
2019/10/06 04:08 android-4.14 ed203b32ee7e f3f7d9c8 .config console log report ci-android-414-kasan-gce-root
2019/08/16 03:52 android-4.14 0e28694fe668 8fd428a1 .config console log report ci-android-414-kasan-gce-root
2019/07/27 06:33 android-4.14 54fa720a6f32 c85e1c5b .config console log report ci-android-414-kasan-gce-root
2019/06/27 00:38 android-4.14 93c338c2e7ba 7509bf36 .config console log report ci-android-414-kasan-gce-root
2019/06/08 13:12 android-4.14 76896566d7b9 cf9c3a50 .config console log report ci-android-414-kasan-gce-root
2019/06/08 06:46 android-4.14 76896566d7b9 cf9c3a50 .config console log report ci-android-414-kasan-gce-root
2019/02/14 14:22 android-4.14 578e66bf09f9 6a46f448 .config console log report ci-android-414-kasan-gce-root
2018/09/29 11:22 android-4.14 56aae8ee7423 41e4b329 .config console log report ci-android-414-kasan-gce-root
2018/09/03 18:41 android-4.14 47350a9f13c6 a4718693 .config console log report ci-android-414-kasan-gce-root
* Struck through repros no longer work on HEAD.