INFO: task hung in do

[upstream] INFO: task hung in do_exit
Status: moderation: reported on 2018/04/23 01:02
Reported-by: syzbot+8a19c77ce070f0d4d3bb@syzkaller.appspotmail.com
First: 156d, last: 20d

Sample crash report:

kworker/dying (4918) used greatest stack depth: 14040 bytes left
kworker/dying (67) used greatest stack depth: 12776 bytes left
INFO: task syz-executor1:24583 blocked for more than 140 seconds.
      Not tainted 4.18.0-rc5+ #156
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor1   D23888 24583   4538 0x80000004
Call Trace:
 context_switch kernel/sched/core.c:2853 [inline]
 __schedule+0x87c/0x1ed0 kernel/sched/core.c:3501
 schedule+0xfb/0x450 kernel/sched/core.c:3545
 __rwsem_down_read_failed_common kernel/locking/rwsem-xadd.c:269 [inline]
 rwsem_down_read_failed+0x362/0x600 kernel/locking/rwsem-xadd.c:286
 call_rwsem_down_read_failed+0x18/0x30 arch/x86/lib/rwsem.S:94
 __down_read arch/x86/include/asm/rwsem.h:83 [inline]
 down_read+0xc3/0x1d0 kernel/locking/rwsem.c:26
 exit_mm kernel/exit.c:510 [inline]
 do_exit+0x593/0x2750 kernel/exit.c:852
 do_group_exit+0x177/0x440 kernel/exit.c:968
 get_signal+0x88e/0x1970 kernel/signal.c:2468
 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816
 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455b0a
Code: 20 48 8b 4c 24 18 48 39 c8 0f 8d 80 01 00 00 0f 87 9a 01 00 00 48 29 c1 48 89 ca 48 f7 d9 48 c1 f9 3f 48 21 c1 48 85 d2 0f 86 <7a> 01 00 00 48 8b 5c 24 10 0f b6 34 0b 8d 7e 40 40 80 ff 20 73 52 
RSP: 002b:00007ffe4aafb158 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000455b0a
RDX: 0000000000000003 RSI: 0000000000021000 RDI: 0000000000000000
RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000020022 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000021000 R14: 0000000000020022 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/901:
 #0: 00000000b574df0d (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461
1 lock held by rsyslogd/4401:
 #0: 000000000fce786d (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766
2 locks held by getty/4491:
 #0: 00000000d7ac7651 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000ec8bb5e9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4492:
 #0: 0000000014e48326 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000044d77b37 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4493:
 #0: 000000005a8c9bc2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000c1655c5d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4494:
 #0: 00000000c8211079 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000006adae884 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4495:
 #0: 000000002cb3cdca (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000f6bb3c9e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4496:
 #0: 00000000c6096425 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000bc812a1d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
2 locks held by getty/4497:
 #0: 00000000bd814cc2 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000007cfb718c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140
1 lock held by syz-executor1/24583:
 #0: 00000000d7f983f1 (&mm->mmap_sem){++++}, at: exit_mm kernel/exit.c:510 [inline]
 #0: 00000000d7f983f1 (&mm->mmap_sem){++++}, at: do_exit+0x593/0x2750 kernel/exit.c:852
3 locks held by syz-executor1/24593:

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

NMI backtrace for cpu 1
CPU: 1 PID: 901 Comm: khungtaskd Not tainted 4.18.0-rc5+ #156
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+0x1c9/0x2b4 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_uninterruptible_tasks kernel/hung_task.c:196 [inline]
 watchdog+0x9c4/0xf80 kernel/hung_task.c:252
 kthread+0x345/0x410 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412
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

All crashes (4):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Maintainers
ci-upstream-kasan-gce-root	2018/07/21 01:15	upstream	28c20cc7	af255b09	.config	log	report	akpm@linux-foundation.org, ebiederm@xmission.com, keescook@chromium.org, linux-kernel@vger.kernel.org, linux@dominikbrodowski.net, mark.rutland@arm.com, mingo@kernel.org, paulmck@linux.vnet.ibm.com, sudipm.mukherjee@gmail.com, viro@zeniv.linux.org.uk
ci-upstream-net-kasan-gce	2018/04/20 23:48	net-next	0263ea5c	cc402841	.config	log	report	akpm@linux-foundation.org, keescook@chromium.org, linux-kernel@vger.kernel.org, mingo@kernel.org, paulmck@linux.vnet.ibm.com, viro@zeniv.linux.org.uk
ci-upstream-linux-next-kasan-gce-root	2018/09/03 20:17	linux-next	dceb9092	a4718693	.config	log	report	akpm@linux-foundation.org, ebiederm@xmission.com, keescook@chromium.org, linux-kernel@vger.kernel.org, mcgrof@kernel.org, sudipm.mukherjee@gmail.com, viro@zeniv.linux.org.uk
ci-upstream-linux-next-kasan-gce-root	2018/07/30 08:29	linux-next	d1e0b8e0	1a381291	.config	log	report	akpm@linux-foundation.org, byungchul.park@lge.com, j@bitron.ch, keescook@chromium.org, linux-kernel@vger.kernel.org, mingo@kernel.org, paulmck@linux.vnet.ibm.com, sudipm.mukherjee@gmail.com, viro@zeniv.linux.org.uk