[v5.15] INFO: rcu detected stall in shmem_fault

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Sep 2, 2023, 7:17:08 AM9/2/23
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Hello,

syzbot found the following issue on:

HEAD commit: 8f790700c974 Linux 5.15.130
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1649b1a8680000
kernel config: https://syzkaller.appspot.com/x/.config?x=a22cff001b9b10b3
dashboard link: https://syzkaller.appspot.com/bug?extid=d6c35aa64dbdb340d430
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/97d68b3e1757/disk-8f790700.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4ecbd3f0457b/vmlinux-8f790700.xz
kernel image: https://storage.googleapis.com/syzbot-assets/68019fbed619/bzImage-8f790700.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d6c35a...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (0 ticks this GP) idle=b13/1/0x4000000000000000 softirq=194954/194954 fqs=0
(detected by 0, t=10505 jiffies, g=326209, q=101)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 20928 Comm: syz-executor.2 Not tainted 5.15.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:instrument_atomic_read include/linux/instrumented.h:71 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:344 [inline]
RIP: 0010:cpu_online include/linux/cpumask.h:895 [inline]
RIP: 0010:trace_lock_acquire include/trace/events/lock.h:13 [inline]
RIP: 0010:lock_acquire+0xc2/0x4f0 kernel/locking/lockdep.c:5593
Code: f3 f3 43 c6 44 2c 17 f3 0f 1f 44 00 00 65 8b 1d 8c 98 9f 7e 83 fb 08 0f 83 e2 02 00 00 89 d8 c1 e8 06 48 8d 3c c5 68 09 e4 8d <be> 08 00 00 00 e8 74 42 67 00 89 d8 48 0f a3 05 72 8c 81 0c 73 0d
RSP: 0000:ffffc90000dd0b40 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8de40968
RBP: ffffc90000dd0c98 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920001ba170
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888016d1c658
FS: 00005555571e8480(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d422000 CR3: 0000000082c56000 CR4: 00000000003506e0
DR0: 00000000000b2981 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:363 [inline]
advance_sched+0x47/0x940 net/sched/sch_taprio.c:716
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
__sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:i_size_read include/linux/fs.h:895 [inline]
RIP: 0010:shmem_getpage_gfp+0x28c/0x3190 mm/shmem.c:1834
Code: 48 8b 9c 24 e8 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 f7 d6 19 00 4c 8b 3b <48> 8b 9c 24 18 01 00 00 48 89 df 4c 89 fe e8 01 38 d0 ff 4c 39 fb
RSP: 0000:ffffc900062f78c0 EFLAGS: 00000246
RAX: 1ffff11003589bd8 RBX: ffff88801ac4dec0 RCX: dffffc0000000000
RDX: ffff888016d1bb80 RSI: 0000000000000002 RDI: 0000000000000004
RBP: ffffc900062f7aa0 R08: ffffffff81afe67c R09: ffff888019a9c528
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000002
R13: ffffc900062f7df0 R14: ffffc900062f7b20 R15: 0000000001000000
shmem_fault+0x1d7/0x700 mm/shmem.c:2118
__do_fault+0x139/0x340 mm/memory.c:3898
do_shared_fault mm/memory.c:4288 [inline]
do_fault mm/memory.c:4366 [inline]
handle_pte_fault mm/memory.c:4621 [inline]
__handle_mm_fault mm/memory.c:4756 [inline]
handle_mm_fault+0x275d/0x5950 mm/memory.c:4854
do_user_addr_fault arch/x86/mm/fault.c:1397 [inline]
handle_page_fault arch/x86/mm/fault.c:1485 [inline]
exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1541
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0x7f82b4e44226
Code: 1f 44 00 00 48 8b 0d c9 e4 c9 00 4c 63 05 b2 e4 c9 00 48 8b 05 b3 e4 c9 00 49 01 c8 48 39 c8 72 13 4c 39 c0 73 0e 48 8d 50 04 <89> 38 48 89 15 99 e4 c9 00 c3 52 48 8d 35 03 ff 09 00 48 89 c2 48
RSP: 002b:00007fff445eace8 EFLAGS: 00010287
RAX: 0000001b2d422000 RBX: 00007f82b4fb9018 RCX: 0000001b2d420000
RDX: 0000001b2d422004 RSI: 0000000080000000 RDI: 000000008506b666
RBP: 000000008506b666 R08: 0000001b2da20000 R09: 0000000000001666
R10: 000000008506b66a R11: 0000000000000246 R12: 00000000000036e0
R13: 0000000000000001 R14: 00007f82b4fad000 R15: ffffffff8506bef7
</TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g326209 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=213267
rcu: rcu_preempt kthread starved for 10505 jiffies! g326209 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:26520 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5026 [inline]
__schedule+0x12c4/0x4590 kernel/sched/core.c:6372
schedule+0x11b/0x1f0 kernel/sched/core.c:6455
schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1884
rcu_gp_fqs_loop+0x2af/0xf70 kernel/rcu/tree.c:1959
rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2132
kthread+0x3f6/0x4f0 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
</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: 20928 Comm: syz-executor.2 Not tainted 5.15.130-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:get_current arch/x86/include/asm/current.h:15 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:217 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x4/0x80 kernel/kcov.c:270
Code: 48 c7 44 11 08 06 00 00 00 48 89 7c 11 10 48 89 74 11 18 4c 89 44 11 20 49 ff c2 4c 89 12 c3 0f 1f 80 00 00 00 00 4c 8b 04 24 <65> 48 8b 15 44 50 82 7e 65 8b 05 45 50 82 7e a9 00 01 ff 00 74 10
RSP: 0000:ffffc90000dd0d38 EFLAGS: 00000046
RAX: 0000000080010001 RBX: 0000000000000001 RCX: ffffffff816f6579
RDX: ffff888016d1bb80 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90000dd0e01 R08: ffffffff816f65a1 R09: fffffbfff1bc812e
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff8880b9b2a200
R13: ffff8880b9b2a300 R14: ffff88807f2b8b40 R15: dffffc0000000000
FS: 00005555571e8480(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d422000 CR3: 0000000082c56000 CR4: 00000000003506e0
DR0: 00000000000b2981 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<NMI>
</NMI>
<IRQ>
variable_test_bit arch/x86/include/asm/bitops.h:219 [inline]
test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline]
cpumask_test_cpu include/linux/cpumask.h:344 [inline]
cpu_online include/linux/cpumask.h:895 [inline]
trace_hrtimer_cancel include/trace/events/timer.h:294 [inline]
debug_deactivate+0x81/0x1e0 kernel/time/hrtimer.c:482
__run_hrtimer kernel/time/hrtimer.c:1653 [inline]
__hrtimer_run_queues+0x31d/0xcf0 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1085 [inline]
__sysvec_apic_timer_interrupt+0x139/0x470 arch/x86/kernel/apic/apic.c:1102
sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1096
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0010:i_size_read include/linux/fs.h:895 [inline]
RIP: 0010:shmem_getpage_gfp+0x28c/0x3190 mm/shmem.c:1834
Code: 48 8b 9c 24 e8 00 00 00 48 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 48 89 df e8 f7 d6 19 00 4c 8b 3b <48> 8b 9c 24 18 01 00 00 48 89 df 4c 89 fe e8 01 38 d0 ff 4c 39 fb
RSP: 0000:ffffc900062f78c0 EFLAGS: 00000246
RAX: 1ffff11003589bd8 RBX: ffff88801ac4dec0 RCX: dffffc0000000000
RDX: ffff888016d1bb80 RSI: 0000000000000002 RDI: 0000000000000004
RBP: ffffc900062f7aa0 R08: ffffffff81afe67c R09: ffff888019a9c528
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000002
R13: ffffc900062f7df0 R14: ffffc900062f7b20 R15: 0000000001000000
shmem_fault+0x1d7/0x700 mm/shmem.c:2118
__do_fault+0x139/0x340 mm/memory.c:3898
do_shared_fault mm/memory.c:4288 [inline]
do_fault mm/memory.c:4366 [inline]
handle_pte_fault mm/memory.c:4621 [inline]
__handle_mm_fault mm/memory.c:4756 [inline]
handle_mm_fault+0x275d/0x5950 mm/memory.c:4854
do_user_addr_fault arch/x86/mm/fault.c:1397 [inline]
handle_page_fault arch/x86/mm/fault.c:1485 [inline]
exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1541
asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
RIP: 0033:0x7f82b4e44226
Code: 1f 44 00 00 48 8b 0d c9 e4 c9 00 4c 63 05 b2 e4 c9 00 48 8b 05 b3 e4 c9 00 49 01 c8 48 39 c8 72 13 4c 39 c0 73 0e 48 8d 50 04 <89> 38 48 89 15 99 e4 c9 00 c3 52 48 8d 35 03 ff 09 00 48 89 c2 48
RSP: 002b:00007fff445eace8 EFLAGS: 00010287
RAX: 0000001b2d422000 RBX: 00007f82b4fb9018 RCX: 0000001b2d420000
RDX: 0000001b2d422004 RSI: 0000000080000000 RDI: 000000008506b666
RBP: 000000008506b666 R08: 0000001b2da20000 R09: 0000000000001666
R10: 000000008506b66a R11: 0000000000000246 R12: 00000000000036e0
R13: 0000000000000001 R14: 00007f82b4fad000 R15: ffffffff8506bef7
</TASK>


---
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syzbot

unread,
Dec 11, 2023, 6:17:14 AM12/11/23
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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