[v6.1] INFO: rcu detected stall in cleanup_mnt

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Aug 4, 2023, 8:07:03 PM8/4/23
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Hello,

syzbot found the following issue on:

HEAD commit: 52a953d0934b Linux 6.1.43
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1412a286a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f82b602d1c7479e
dashboard link: https://syzkaller.appspot.com/bug?extid=f9542c17991876acad46
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dd5f1ccdac03/disk-52a953d0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a9532c041c65/vmlinux-52a953d0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f8e450b46aed/bzImage-52a953d0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+f9542c...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 ticks this GP) idle=f42c/1/0x4000000000000000 softirq=26549/26549 fqs=0
(detected by 0, t=10502 jiffies, g=34905, q=99 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7348 Comm: syz-executor.5 Not tainted 6.1.43-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:__kasan_check_read+0x6/0x10 mm/kasan/shadow.c:31
Code: 41 5e 41 5f 5d c3 48 c7 c7 0d 91 98 8c eb 0a 48 c7 c7 45 91 98 8c 4c 89 fe e8 1f 31 a2 08 31 db eb d7 cc cc 89 f6 48 8b 0c 24 <31> d2 e9 d3 ec ff ff 0f 1f 00 89 f6 48 8b 0c 24 ba 01 00 00 00 e9
RSP: 0018:ffffc900001e0d58 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000002 RCX: ffffffff817946be
RDX: 0000000000010000 RSI: 0000000000000008 RDI: ffffffff8e736fe8
RBP: ffffc900001e0eb0 R08: ffffffff81794694 R09: ffffed1017325499
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff88b63a90
R13: 0000000000000001 R14: ffff8880b992a4c0 R15: 0000000000000001
FS: 0000555556a42480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff3f66c66e4 CR3: 0000000036c4c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
instrument_atomic_read include/linux/instrumented.h:72 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
cpumask_test_cpu include/linux/cpumask.h:444 [inline]
cpu_online include/linux/cpumask.h:1030 [inline]
trace_hrtimer_expire_entry include/trace/events/timer.h:239 [inline]
__run_hrtimer kernel/time/hrtimer.c:1682 [inline]
__hrtimer_run_queues+0x50e/0xe50 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline]
__sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1112
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:synchronize_rcu+0x0/0x3f0 kernel/rcu/tree.c:3512
Code: 5e 41 5f e9 52 0e e6 ff 5b 41 5c 41 5e 41 5f c3 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c d9 fe ff ff e8 45 68 6d 00 e9 cf fe ff ff <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 40 01
RSP: 0018:ffffc900052e7b78 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff92000a5cf78 RCX: ffffffff91c8f103
RDX: 0000000000000001 RSI: ffffffff8aebe480 RDI: ffffffff8b3cdde0
RBP: ffffc900052e7c58 R08: dffffc0000000000 R09: fffffbfff238f8f5
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff91c7a8d8
R13: 1ffff92000a5cf74 R14: 0000000000000203 R15: ffffc900052e7bc0
lockdep_unregister_key+0x4e4/0x5b0 kernel/locking/lockdep.c:6362
wq_unregister_lockdep kernel/workqueue.c:3500 [inline]
destroy_workqueue+0x81f/0xae0 kernel/workqueue.c:4469
xfs_fs_put_super+0x23f/0x2c0 fs/xfs/xfs_super.c:1125
generic_shutdown_super+0x130/0x340 fs/super.c:501
kill_block_super+0x7a/0xe0 fs/super.c:1450
deactivate_locked_super+0xa0/0x110 fs/super.c:332
cleanup_mnt+0x490/0x520 fs/namespace.c:1186
task_work_run+0x246/0x300 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fda35e7de17
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd366e6af8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fda35e7de17
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffd366e6bb0
RBP: 00007ffd366e6bb0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd366e7c70
R13: 00007fda35ec73b9 R14: 000000000007b64a R15: 000000000000000a
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g34905 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=20158
rcu: rcu_preempt kthread starved for 10502 jiffies! g34905 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:I stack:26712 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5241 [inline]
__schedule+0x132c/0x4330 kernel/sched/core.c:6554
schedule+0xbf/0x180 kernel/sched/core.c:6630
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935
rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1661
rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1860
kthread+0x26e/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 7348 Comm: syz-executor.5 Not tainted 6.1.43-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
RIP: 0010:mark_lock+0xe8/0x340 kernel/locking/lockdep.c:4613
Code: e8 03 42 0f b6 04 28 84 c0 0f 85 0f 02 00 00 83 3d 4c a9 5e 10 00 74 39 31 db 48 83 c3 50 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 ae 33 76 00 41 bc 01 00 00 00 44 85 33 74 53 44
RSP: 0018:ffffc900001e0a18 EFLAGS: 00000046
RAX: 1ffffffff2044466 RBX: ffffffff90222330 RCX: ffffffff816a47da
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff904973a8
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff2092e76
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880818ba898
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880818ba8c8
FS: 0000555556a42480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff3f66c66e4 CR3: 0000000036c4c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
mark_usage kernel/locking/lockdep.c:4527 [inline]
__lock_acquire+0xb40/0x1f80 kernel/locking/lockdep.c:5010
lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5669
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:350 [inline]
advance_sched+0x47/0x940 net/sched/sch_taprio.c:700
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x5e5/0xe50 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1095 [inline]
__sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1112
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1106
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649
RIP: 0010:synchronize_rcu+0x0/0x3f0 kernel/rcu/tree.c:3512
Code: 5e 41 5f e9 52 0e e6 ff 5b 41 5c 41 5e 41 5f c3 89 f9 80 e1 07 80 c1 03 38 c1 0f 8c d9 fe ff ff e8 45 68 6d 00 e9 cf fe ff ff <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 40 01
RSP: 0018:ffffc900052e7b78 EFLAGS: 00000206
RAX: dffffc0000000000 RBX: 1ffff92000a5cf78 RCX: ffffffff91c8f103
RDX: 0000000000000001 RSI: ffffffff8aebe480 RDI: ffffffff8b3cdde0
RBP: ffffc900052e7c58 R08: dffffc0000000000 R09: fffffbfff238f8f5
R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff91c7a8d8
R13: 1ffff92000a5cf74 R14: 0000000000000203 R15: ffffc900052e7bc0
lockdep_unregister_key+0x4e4/0x5b0 kernel/locking/lockdep.c:6362
wq_unregister_lockdep kernel/workqueue.c:3500 [inline]
destroy_workqueue+0x81f/0xae0 kernel/workqueue.c:4469
xfs_fs_put_super+0x23f/0x2c0 fs/xfs/xfs_super.c:1125
generic_shutdown_super+0x130/0x340 fs/super.c:501
kill_block_super+0x7a/0xe0 fs/super.c:1450
deactivate_locked_super+0xa0/0x110 fs/super.c:332
cleanup_mnt+0x490/0x520 fs/namespace.c:1186
task_work_run+0x246/0x300 kernel/task_work.c:179
resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
exit_to_user_mode_loop+0xd9/0x100 kernel/entry/common.c:171
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297
do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fda35e7de17
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd366e6af8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fda35e7de17
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007ffd366e6bb0
RBP: 00007ffd366e6bb0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd366e7c70
R13: 00007fda35ec73b9 R14: 000000000007b64a R15: 000000000000000a
</TASK>


---
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syzbot

unread,
Nov 12, 2023, 7:06:12 PM11/12/23
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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