rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (0 ticks this GP) idle=0d1/1/0x4000000000000002 softirq=172573/172573 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3561
(detected by 1, t=10505 jiffies, g=237821, q=579)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3561 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline]
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [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+0xb9/0x400 kernel/locking/lockdep.c:5594
Code: 35 a4 12 a5 7e 41 83 fe 08 0f 83 a2 01 00 00 44 89 f0 c1 e8 06 48 8d 3c c5 a8 d8 89 8d be 08 00 00 00 e8 7a 22 61 00 44 89 f0 <48> 0f a3 05 c7 d5 2c 0c 73 0d e8 a8 ce 07 00 84 c0 0f 84 2d 02 00
RSP: 0018:ffffc90002efece0 EFLAGS: 00000056
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff815d02d6
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d89d8a8
RBP: ffffc90002efedf8 R08: ffffffff8d89d8af R09: 1ffffffff1b13b15
R10: dffffc0000000000 R11: fffffbfff1b13b16 R12: ffffffff8c31eaa0
R13: 1ffff920005dfda8 R14: 0000000000000000 R15: dffffc0000000000
FS: 00007fc4bfd59880(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e0c8a5ff8 CR3: 000000002a41a000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
rcu_read_lock include/linux/rcupdate.h:740 [inline]
__perf_event_output kernel/events/core.c:7800 [inline]
perf_event_output_forward+0xbc/0x2e0 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 c2 ef 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90002eff4a0 EFLAGS: 00000206
RAX: e2baf956605df300 RBX: 1ffff920005dfe98 RCX: e2baf956605df300
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: ffffc90002eff578 R08: ffffffff901d116f R09: 1ffffffff203a22d
R10: dffffc0000000000 R11: fffffbfff203a22e R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8c322fe0
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
d_alloc_parallel+0x107b/0x1330 fs/dcache.c:2673
__lookup_slow+0x134/0x410 fs/namei.c:1656
lookup_slow+0x53/0x70 fs/namei.c:1688
walk_component+0x319/0x460 fs/namei.c:1984
link_path_walk+0x665/0xd70 fs/namei.c:-1
path_openat+0x28d/0x2fa0 fs/namei.c:3746
do_filp_open+0x1e2/0x410 fs/namei.c:3777
do_sys_openat2+0x150/0x4b0 fs/open.c:1255
do_sys_open fs/open.c:1271 [inline]
__do_sys_openat fs/open.c:1287 [inline]
__se_sys_openat fs/open.c:1282 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1282
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: 0033:0x7fc4bfe47407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff33c24b80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc4bfd59880 RCX: 00007fc4bfe47407
RDX: 0000000000080000 RSI: 00007fff33c24d00 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000562c7908a7f5
R13: 0000562c7908a7f5 R14: 0000000000000001 R15: 0000000000000000
task:udevd state:R running task stack:22256 pid: 3561 ppid: 1 flags:0x0000400a
Call Trace:
rcu: rcu_preempt kthread timer wakeup didn't happen for 10504 jiffies! g237821 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=84954
rcu: rcu_preempt kthread starved for 10505 jiffies! g237821 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:27416 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x184/0x2d0 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3561 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_lock_acquire+0xe/0x30 include/linux/rcupdate.h:313
Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c 28 ff ff ff 48 89 df e8 95 cc 23 00 e9 1b ff ff ff 53 48 89 fb e8 77 c8 de ff e8 72 c8 de ff <48> 89 df 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 68 29 57 9a
RSP: 0018:ffffc90002efee10 EFLAGS: 00000093
RAX: ffffffff819a572e RBX: ffffffff8c31eaa0 RCX: ffff88807d0b9dc0
RDX: 0000000000000000 RSI: ffffc90002eff080 RDI: ffffffff8c31eaa0
RBP: ffffc90002efef38 R08: ffff88805d4cefe3 R09: 1ffff1100ba99dfc
R10: dffffc0000000000 R11: ffffed100ba99dfd R12: dffffc0000000000
R13: 1ffff920005dfdc8 R14: dffffc0000000000 R15: ffffc90002eff080
FS: 00007fc4bfd59880(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5e0c8a5ff8 CR3: 000000002a41a000 CR4: 00000000003506f0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
rcu_read_lock include/linux/rcupdate.h:740 [inline]
__perf_event_output kernel/events/core.c:7800 [inline]
perf_event_output_forward+0xbc/0x2e0 kernel/events/core.c:7822
__perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
perf_swevent_overflow kernel/events/core.c:9591 [inline]
perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 c2 ef 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90002eff4a0 EFLAGS: 00000206
RAX: e2baf956605df300 RBX: 1ffff920005dfe98 RCX: e2baf956605df300
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f780
RBP: ffffc90002eff578 R08: ffffffff901d116f R09: 1ffffffff203a22d
R10: dffffc0000000000 R11: fffffbfff203a22e R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000246 R15: ffffffff8c322fe0
__rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
rcu_read_unlock include/linux/rcupdate.h:772 [inline]
d_alloc_parallel+0x107b/0x1330 fs/dcache.c:2673
__lookup_slow+0x134/0x410 fs/namei.c:1656
lookup_slow+0x53/0x70 fs/namei.c:1688
walk_component+0x319/0x460 fs/namei.c:1984
link_path_walk+0x665/0xd70 fs/namei.c:-1
path_openat+0x28d/0x2fa0 fs/namei.c:3746
do_filp_open+0x1e2/0x410 fs/namei.c:3777
do_sys_openat2+0x150/0x4b0 fs/open.c:1255
do_sys_open fs/open.c:1271 [inline]
__do_sys_openat fs/open.c:1287 [inline]
__se_sys_openat fs/open.c:1282 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1282
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: 0033:0x7fc4bfe47407
Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fff33c24b80 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc4bfd59880 RCX: 00007fc4bfe47407
RDX: 0000000000080000 RSI: 00007fff33c24d00 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000562c7908a7f5
R13: 0000562c7908a7f5 R14: 0000000000000001 R15: 0000000000000000