rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (0 ticks this GP) idle=9a1/1/0x4000000000000000 softirq=9722/9722 fqs=0 
	(detected by 1, t=10506 jiffies, g=11805, q=1549)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4947 Comm: syz.3.34 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:__lock_acquire+0x12d2/0x7d10 kernel/locking/lockdep.c:5009
Code: 48 83 3b 00 0f 84 f0 49 00 00 48 8b 44 24 58 42 0f b6 04 00 84 c0 0f 85 b2 5a 00 00 41 8b 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03 <25> f8 03 00 00 48 8d b8 c0 20 1d 90 be 08 00 00 00 e8 f8 14 61 00
RSP: 0018:ffffc900036af120 EFLAGS: 00000003
RAX: 0000000000014002 RBX: 0000000000000015 RCX: ffffffff815d16fe
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff901d20c0
RBP: ffffc900036af370 R08: dffffc0000000000 R09: 1ffffffff203a418
R10: dffffc0000000000 R11: fffffbfff203a419 R12: 0000000062d6026f
R13: ffff88802a571dc0 R14: 00000000e7c4a6a0 R15: ffff88802a572948
FS:  000055556be3c500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001e133000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313
 rcu_read_lock include/linux/rcupdate.h:740 [inline]
 __perf_output_begin kernel/events/ring_buffer.c:163 [inline]
 perf_output_begin_forward+0xa5/0xa40 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7804 [inline]
 perf_event_output_forward+0x19b/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 e2 f0 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:ffffc900036afcc0 EFLAGS: 00000206
RAX: bd1f22cfb18e7d00 RBX: 1ffff920006d5f9c RCX: bd1f22cfb18e7d00
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f740
RBP: ffffc900036afd88 R08: ffffffff901d20cf R09: 1ffffffff203a419
R10: dffffc0000000000 R11: fffffbfff203a41a R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock+0x85/0x90 include/linux/rcupdate.h:772
 dput+0xc0/0x1a0 fs/dcache.c:886
 __fput+0x5ee/0x930 fs/file_table.c:319
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff087d4bcb9
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:00007ffd968b5158 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd968b5240 RCX: 00007ff087d4bcb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001c67f R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33b20000 R11: 0000000000000246 R12: 00007ffd968b5280
R13: 00007ff087fc6fac R14: 000000000001c6cf R15: 00007ff087fc6fa0
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g11805 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=3705
rcu: rcu_preempt kthread starved for 10506 jiffies! g11805 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:28016 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 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
 </TASK>
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: 4947 Comm: syz.3.34 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:174 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2c/0x60 kernel/kcov.c:206
Code: 04 24 65 48 8b 0d e4 4e 89 7e 65 8b 15 e5 4e 89 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c <8b> 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 48 8b 32 48
RSP: 0018:ffffc900036af7f8 EFLAGS: 00000046
RAX: ffffffff81988382 RBX: 1ffff11017206a35 RCX: ffff88802a571dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002
RBP: ffffc900036afa88 R08: ffffffff8d89db2f R09: 1ffffffff1b13b65
R10: dffffc0000000000 R11: fffffbfff1b13b66 R12: ffff8880b90351a8
R13: ffff88807b2617e0 R14: 0000000000000000 R15: 0000000000000000
FS:  000055556be3c500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001e133000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 perf_tp_event+0x3c2/0xbf0 kernel/events/core.c:10045
 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 e2 f0 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:ffffc900036afcc0 EFLAGS: 00000206
RAX: bd1f22cfb18e7d00 RBX: 1ffff920006d5f9c RCX: bd1f22cfb18e7d00
RDX: dffffc0000000000 RSI: ffffffff8a2b2780 RDI: ffffffff8a79f740
RBP: ffffc900036afd88 R08: ffffffff901d20cf R09: 1ffffffff203a419
R10: dffffc0000000000 R11: fffffbfff203a41a R12: ffffffff8c322f00
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock+0x85/0x90 include/linux/rcupdate.h:772
 dput+0xc0/0x1a0 fs/dcache.c:886
 __fput+0x5ee/0x930 fs/file_table.c:319
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7ff087d4bcb9
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:00007ffd968b5158 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ffd968b5240 RCX: 00007ff087d4bcb9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 000000000001c67f R08: 0000000000000001 R09: 0000000000000000
R10: 0000001b33b20000 R11: 0000000000000246 R12: 00007ffd968b5280
R13: 00007ff087fc6fac R14: 000000000001c6cf R15: 00007ff087fc6fa0
 </TASK>