[v6.1] INFO: rcu detected stall in call_timer_fn (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0182cb5b74ee Linux 6.1.162
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1045765a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0605c5af04d7603
dashboard link: https://syzkaller.appspot.com/bug?extid=c6428c3197b4f8889769
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8b6fc106fd9c/disk-0182cb5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f9ed1286c8af/vmlinux-0182cb5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/10c7fc900d05/bzImage-0182cb5b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6428c...@syzkaller.appspotmail.com

rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2685 jiffies s: 115497 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 14412 Comm: syz.3.3219 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:182 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x64/0xe0 kernel/kcov.c:349
Code: 26 90 8a 48 8b 54 24 20 65 4c 8b 05 e6 f6 7f 7e 45 31 c9 eb 08 49 ff c1 4c 39 c8 74 77 4e 8b 54 ce 10 65 44 8b 1d d4 f6 7f 7e <41> 81 e3 00 01 ff 00 74 13 41 81 fb 00 01 00 00 75 d9 41 83 b8 1c
RSP: 0018:ffffc900001e0090 EFLAGS: 00000012
RAX: 0000000000000020 RBX: 000000a6eda8dd96 RCX: 0000000000000005
RDX: ffffffff81857eac RSI: ffffffff8cb75f80 RDI: 0000000000000004
RBP: 0000000000000004 R08: ffff88802da90000 R09: 000000000000001c
R10: 000000000000001c R11: 0000000000000106 R12: 0000000000115a64
R13: 00000000000005dc R14: dffffc0000000000 R15: ffff8880177b95ec
FS: 00007f5f3ad1b6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000012c0 CR3: 000000002e264000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000008d24
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
check_buffer+0x2ac/0x900 kernel/trace/ring_buffer.c:3490
__rb_reserve_next+0x511/0xd70 kernel/trace/ring_buffer.c:3619
rb_reserve_next_event kernel/trace/ring_buffer.c:3754 [inline]
ring_buffer_lock_reserve+0xafa/0xf10 kernel/trace/ring_buffer.c:3813
__trace_buffer_lock_reserve kernel/trace/trace.c:956 [inline]
trace_event_buffer_lock_reserve+0x1ce/0x6f0 kernel/trace/trace.c:2843
trace_event_buffer_reserve+0x2a8/0x3d0 kernel/trace/trace_events.c:647
do_trace_event_raw_event_bpf_trace_printk kernel/trace/bpf_trace.h:11 [inline]
trace_event_raw_event_bpf_trace_printk+0x112/0x230 kernel/trace/bpf_trace.h:11
trace_bpf_trace_printk+0x199/0x220 kernel/trace/bpf_trace.h:11
____bpf_trace_printk kernel/trace/bpf_trace.c:391 [inline]
bpf_trace_printk+0x13e/0x1c0 kernel/trace/bpf_trace.c:374
bpf_prog_61352b8a56410a06+0x3b/0x3f
bpf_dispatcher_nop_func include/linux/bpf.h:1012 [inline]
__bpf_prog_run include/linux/filter.h:607 [inline]
bpf_prog_run include/linux/filter.h:614 [inline]
bpf_prog_run_array include/linux/bpf.h:1668 [inline]
trace_call_bpf+0x322/0x6b0 kernel/trace/bpf_trace.c:135
perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:9997
perf_trace_preemptirq_template+0x268/0x320 include/trace/events/preemptirq.h:14
trace_irq_disable include/trace/events/preemptirq.h:36 [inline]
trace_hardirqs_off_finish+0x13f/0x180 kernel/trace/trace_preemptirq.c:67
irqentry_enter+0x33/0x50 kernel/entry/common.c:382
sysvec_apic_timer_interrupt+0xa/0xc0 arch/x86/kernel/apic/apic.c:1118
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xbc/0x120 kernel/locking/spinlock.c:194
Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 0f 3c 22 f7 65 8b 05 d0 c0 cb 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc900001e09c0 EFLAGS: 00000206
RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 2fe72c8d2f02d800
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: 0000000000000001
RBP: ffffc900001e0a50 R08: ffffffff90af42d7 R09: 1ffffffff215e85a
R10: dffffc0000000000 R11: fffffbfff215e85b R12: dffffc0000000000
R13: ffff888076ab5e00 R14: ffffffff96f005c8 R15: 1ffff9200003c138
debug_object_assert_init+0x1ed/0x2f0 lib/debugobjects.c:889
debug_timer_assert_init kernel/time/timer.c:792 [inline]
debug_assert_init kernel/time/timer.c:837 [inline]
__mod_timer+0x54/0xd00 kernel/time/timer.c:1020
call_timer_fn+0x1ac/0x670 kernel/time/timer.c:1701
expire_timers kernel/time/timer.c:1752 [inline]
__run_timers+0x53e/0x800 kernel/time/timer.c:2023
run_timer_softirq+0x63/0xf0 kernel/time/timer.c:2036
handle_softirqs+0x2a1/0x930 kernel/softirq.c:596
__do_softirq kernel/softirq.c:630 [inline]
invoke_softirq kernel/softirq.c:470 [inline]
__irq_exit_rcu+0x13b/0x230 kernel/softirq.c:679
irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
</IRQ>
<TASK>
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:finish_task_switch+0x26a/0x8f0 kernel/sched/core.c:5124
Code: 0f 84 3b 01 00 00 48 85 db 0f 85 5a 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 d0 fd dc 08 e8 eb 2c 2f 00 fb 4c 8b 65 c0 <49> 8d bc 24 f8 15 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffc900034f7a38 EFLAGS: 00000282
RAX: 2fe72c8d2f02d800 RBX: 0000000000000000 RCX: 2fe72c8d2f02d800
RDX: dffffc0000000000 RSI: ffffffff8a8c1220 RDI: ffffffff8adf0d20
RBP: ffffc900034f7a90 R08: ffffffff90af4287 R09: 1ffffffff215e850
R10: dffffc0000000000 R11: fffffbfff215e851 R12: ffff88802da90000
R13: dffffc0000000000 R14: ffff88802a935940 R15: ffff8880b8f3b5d0
context_switch kernel/sched/core.c:5248 [inline]
__schedule+0x11d9/0x40e0 kernel/sched/core.c:6562
preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__list_add include/linux/list.h:-1 [inline]
RIP: 0010:list_add_tail include/linux/list.h:102 [inline]
RIP: 0010:__do_sys_perf_event_open kernel/events/core.c:12797 [inline]
RIP: 0010:__se_sys_perf_event_open+0x1be5/0x1ec0 kernel/events/core.c:12378
Code: 89 ef e8 0e 70 2d 00 4d 89 75 00 4c 89 f0 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 80 3c 08 00 74 08 4c 89 f7 e8 eb 6f 2d 00 <48> 8b 44 24 18 48 8b 4c 24 10 48 89 88 f0 02 00 00 48 05 f8 02 00
RSP: 0018:ffffc900034f7da0 EFLAGS: 00000246
RAX: 1ffff1100e8e195e RBX: ffff88807470e2f0 RCX: dffffc0000000000
RDX: ffffc9000ec91000 RSI: 0000000000000efa RDI: 0000000000000efb
RBP: ffffc900034f7f10 R08: ffffffff8e1fcb6f R09: 1ffffffff1c3f96d
R10: dffffc0000000000 R11: fffffbfff1c3f96e R12: 1ffff11005b5229a
R13: ffff88802da914d0 R14: ffff88807470caf0 R15: 1ffff9200069efc0
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5f39d9aeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5f3ad1b028 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: ffffffffffffffda RBX: 00007f5f3a015fa0 RCX: 00007f5f39d9aeb9
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 00002000000012c0
RBP: 00007f5f39e08c1f R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5f3a016038 R14: 00007f5f3a015fa0 R15: 00007ffcc497cfa8
</TASK>


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