[v5.15] INFO: rcu detected stall in __run_timers (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 01879f56bdde Linux 5.15.190
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=124a3e34580000
kernel config: https://syzkaller.appspot.com/x/.config?x=4bfb7f3ca9a4e172
dashboard link: https://syzkaller.appspot.com/bug?extid=cd14d7355b2f09d8aa58
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/17385e3d0303/disk-01879f56.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f9f55c135c1d/vmlinux-01879f56.xz
kernel image: https://storage.googleapis.com/syzbot-assets/aa5c288de53c/bzImage-01879f56.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cd14d7...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 0-....: (10120 ticks this GP) idle=173/1/0x4000000000000000 softirq=30762/30762 fqs=5248
(t=10501 jiffies g=44357 q=178714)
NMI backtrace for cpu 0
CPU: 0 PID: 9370 Comm: syz.7.894 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
<IRQ>
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x6d8/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1690 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 8e 1d aa f7 48 89 df e8 56 f2 aa f7 e8 d1 8c cb f7 fb bf 01 00 00 00 <e8> a6 15 9f f7 65 8b 05 a7 13 50 76 85 c0 74 02 5b c3 e8 54 1e 4e
RSP: 0018:ffffc90000007c90 EFLAGS: 00000286
RAX: d8cd3550cb4df100 RBX: ffff8880b9028080 RCX: d8cd3550cb4df100
RDX: dffffc0000000000 RSI: ffffffff8a0b1620 RDI: 0000000000000001
RBP: ffffc90000007df0 R08: dffffc0000000000 R09: ffffed101720765a
R10: ffffed101720765a R11: 1ffff11017207659 R12: ffff8880b9028080
R13: 1ffff11017205018 R14: ffff88806288a6f8 R15: ffffc90000007d40
expire_timers kernel/time/timer.c:1495 [inline]
__run_timers+0x516/0x7c0 kernel/time/timer.c:1767
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1780
handle_softirqs+0x328/0x820 kernel/softirq.c:576
__do_softirq kernel/softirq.c:610 [inline]
invoke_softirq kernel/softirq.c:450 [inline]
__irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659
irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline]
sysvec_irq_work+0x9d/0xc0 arch/x86/kernel/irq_work.c:17
</IRQ>
<TASK>
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:finish_lock_switch+0x134/0x280 kernel/sched/core.c:4804
Code: be ff ff ff ff e8 ec 7c 55 08 85 c0 74 4a 4d 85 ff 75 66 0f 1f 44 00 00 48 89 df e8 46 e7 5e 08 e8 71 75 2a 00 fb 48 83 c4 08 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 48 89 df e8 d9 0f fe ff 43 80 3c
RSP: 0018:ffffc90002deefe8 EFLAGS: 00000286
RAX: d8cd3550cb4df100 RBX: ffff8880b903a300 RCX: d8cd3550cb4df100
RDX: dffffc0000000000 RSI: ffffffff8a0b1620 RDI: ffffffff8a59a240
RBP: 1ffff1101720760b R08: dffffc0000000000 R09: ffffed101720765a
R10: ffffed101720765a R11: 1ffff11017207659 R12: 1ffff110172075b9
R13: dffffc0000000000 R14: ffff8880b903adc8 R15: 0000000000000000
finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921
context_switch kernel/sched/core.c:5052 [inline]
__schedule+0x11c3/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
__debug_check_no_obj_freed lib/debugobjects.c:982 [inline]
debug_check_no_obj_freed+0x515/0x530 lib/debugobjects.c:1003
free_pages_prepare mm/page_alloc.c:1345 [inline]
free_pcp_prepare mm/page_alloc.c:1391 [inline]
free_unref_page_prepare+0x237/0x6c0 mm/page_alloc.c:3317
free_unref_page+0x94/0x280 mm/page_alloc.c:3396
qlist_free_all+0x35/0x90 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x150/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x2f/0xd0 mm/kasan/common.c:444
kasan_slab_alloc include/linux/kasan.h:254 [inline]
slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
slab_alloc_node mm/slub.c:3220 [inline]
slab_alloc mm/slub.c:3228 [inline]
kmem_cache_alloc+0x100/0x290 mm/slub.c:3233
kmem_cache_zalloc include/linux/slab.h:725 [inline]
lsm_file_alloc security/security.c:574 [inline]
security_file_alloc+0x30/0x110 security/security.c:1530
__alloc_file+0xc2/0x240 fs/file_table.c:137
alloc_empty_file+0x90/0x180 fs/file_table.c:181
path_openat+0xfc/0x2f30 fs/namei.c:3728
do_filp_open+0x1b3/0x3e0 fs/namei.c:3769
do_sys_openat2+0x142/0x4a0 fs/open.c:1253
do_sys_open fs/open.c:1269 [inline]
__do_sys_openat fs/open.c:1285 [inline]
__se_sys_openat fs/open.c:1280 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1280
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fccdb203550
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 49 94 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 9c 94 02 00 8b 44
RSP: 002b:00007fccd946bf10 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fccdb203550
RDX: 0000000000000002 RSI: 00007fccd946bfa0 RDI: 00000000ffffff9c
RBP: 00007fccd946bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 00007fccdb43c038 R14: 00007fccdb43bfa0 R15: 00007fff68d9ba48
</TASK>


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