syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=89c4/1/0x4000000000000000 softirq=27408/27408 fqs=0
rcu: 	(detected by 0, t=10506 jiffies, g=28697, q=5164 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 8605 Comm: syz.0.2575 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:perf_trace_buf_alloc+0x16c/0x290 kernel/trace/trace_event_perf.c:416
Code: 00 89 ee e8 76 e1 f7 ff 83 fd 03 0f 87 d5 00 00 00 e8 b8 dd f7 ff 4e 8d 34 fd c0 60 ef 96 4c 89 f0 48 c1 e8 03 42 80 3c 28 00 <74> 08 4c 89 f7 e8 9a 23 4f 00 4d 8b 36 e8 a2 75 df 08 89 c5 41 89
RSP: 0018:ffffc900001f0a80 EFLAGS: 00000046
RAX: 1ffffffff2ddec19 RBX: 0000000000000014 RCX: ffff8880234c1e00
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 0000000000000001 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8c7d0a38
R13: dffffc0000000000 R14: ffffffff96ef60c8 R15: 0000000000000001
FS:  0000555580c71500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d863fff CR3: 0000000074441000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 perf_trace_preemptirq_template+0x14a/0x340 include/trace/events/preemptirq.h:14
 trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 a9 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001f0c60 EFLAGS: 00000206
RAX: 7b452cd74dfe8100 RBX: 1ffff9200003e194 RCX: 7b452cd74dfe8100
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc900001f0d48 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000002
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 rebalance_domains+0x89c/0x9d0 kernel/sched/fair.c:11794
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x8/0xb0 kernel/rcu/tree.c:699
Code: e8 dd 77 fd 08 48 c7 c7 00 6a d3 8c 4c 89 f6 e8 5e 75 e1 02 e9 53 ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 41 56 <53> 65 ff 05 28 1a 94 7e e8 bb 8d fd 08 89 c3 83 f8 08 73 60 49 bf
RSP: 0018:ffffc90004f17788 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81678a9b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a84e8
RBP: ffffc90004f178b8 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8192c2d6
R13: dffffc0000000000 R14: 00007f846f18ebe9 R15: 1ffff920009e2f00
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0xba/0x8b0 kernel/locking/lockdep.c:5765
 rcu_lock_release include/linux/rcupdate.h:344 [inline]
 rcu_read_unlock include/linux/rcupdate.h:819 [inline]
 is_bpf_text_address+0x28f/0x2a0 kernel/bpf/core.c:743
 kernel_text_address+0xa0/0xd0 kernel/extable.c:125
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 task_work_add+0xd3/0x440 kernel/task_work.c:77
 fput+0xdd/0x1a0 fs/file_table.c:440
 filp_close+0x10f/0x150 fs/open.c:1545
 __range_close fs/file.c:700 [inline]
 __close_range+0x342/0x630 fs/file.c:757
 __do_sys_close_range fs/open.c:1597 [inline]
 __se_sys_close_range fs/open.c:1594 [inline]
 __x64_sys_close_range+0x7a/0x90 fs/open.c:1594
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f846f18ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffda256b568 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 000000000002ea3b RCX: 00007f846f18ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000002a256b85f
R10: 0000001b2cc20000 R11: 0000000000000246 R12: 00007f846f3b5fac
R13: 00007f846f3b5fa0 R14: ffffffffffffffff R15: 0000000000000005
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g28697 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=9832
rcu: rcu_preempt kthread starved for 10506 jiffies! g28697 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:27528 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6700
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </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: 8605 Comm: syz.0.2575 Not tainted 6.6.101-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215
Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 8c f1 c4 0c 48 89 de 5b e9 63 75 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 60 24 7e 7e 65 8b 15 61 24 7e 7e 81 e2 00 01 ff 00 74
RSP: 0018:ffffc900001f0458 EFLAGS: 00000046
RAX: ffffffff81ac380f RBX: 0000000000000510 RCX: ffff8880234c1e00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900001f0550 R08: dffffc0000000000 R09: 1ffffffff21b46a4
R10: dffffc0000000000 R11: fffffbfff21b46a5 R12: ffffc900001f0840
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000010
FS:  0000555580c71500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d863fff CR3: 0000000074441000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 perf_prepare_sample+0x40f/0x1c40 kernel/events/core.c:7771
 __perf_event_output kernel/events/core.c:7957 [inline]
 perf_event_output_forward+0x152/0x3a0 kernel/events/core.c:7978
 __perf_event_overflow+0x447/0x630 kernel/events/core.c:9703
 perf_swevent_overflow kernel/events/core.c:9779 [inline]
 perf_swevent_event+0x2f5/0x5c0 kernel/events/core.c:-1
 perf_tp_event+0x4f9/0x13a0 kernel/events/core.c:10329
 perf_trace_run_bpf_submit+0xf4/0x1c0 kernel/events/core.c:10253
 perf_trace_preemptirq_template+0x281/0x340 include/trace/events/preemptirq.h:14
 trace_irq_enable+0xbf/0xe0 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:56
 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:723
RIP: 0010:rcu_read_unlock_special+0x88/0x4c0 kernel/rcu/tree_plugin.h:682
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 a9 4e 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001f0c60 EFLAGS: 00000206
RAX: 7b452cd74dfe8100 RBX: 1ffff9200003e194 RCX: 7b452cd74dfe8100
RDX: dffffc0000000000 RSI: ffffffff8aaaba40 RDI: ffffffff8afc6780
RBP: ffffc900001f0d48 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8cd35400
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000002
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 rebalance_domains+0x89c/0x9d0 kernel/sched/fair.c:11794
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__preempt_count_add arch/x86/include/asm/preempt.h:80 [inline]
RIP: 0010:rcu_is_watching+0x8/0xb0 kernel/rcu/tree.c:699
Code: e8 dd 77 fd 08 48 c7 c7 00 6a d3 8c 4c 89 f6 e8 5e 75 e1 02 e9 53 ff ff ff 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 57 41 56 <53> 65 ff 05 28 1a 94 7e e8 bb 8d fd 08 89 c3 83 f8 08 73 60 49 bf
RSP: 0018:ffffc90004f17788 EFLAGS: 00000257
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81678a9b
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8e4a84e8
RBP: ffffc90004f178b8 R08: ffffffff8e4a84ef R09: 1ffffffff1c9509d
R10: dffffc0000000000 R11: fffffbfff1c9509e R12: ffffffff8192c2d6
R13: dffffc0000000000 R14: 00007f846f18ebe9 R15: 1ffff920009e2f00
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0xba/0x8b0 kernel/locking/lockdep.c:5765
 rcu_lock_release include/linux/rcupdate.h:344 [inline]
 rcu_read_unlock include/linux/rcupdate.h:819 [inline]
 is_bpf_text_address+0x28f/0x2a0 kernel/bpf/core.c:743
 kernel_text_address+0xa0/0xd0 kernel/extable.c:125
 __kernel_text_address+0xd/0x30 kernel/extable.c:79
 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369
 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
 __kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
 task_work_add+0xd3/0x440 kernel/task_work.c:77
 fput+0xdd/0x1a0 fs/file_table.c:440
 filp_close+0x10f/0x150 fs/open.c:1545
 __range_close fs/file.c:700 [inline]
 __close_range+0x342/0x630 fs/file.c:757
 __do_sys_close_range fs/open.c:1597 [inline]
 __se_sys_close_range fs/open.c:1594 [inline]
 __x64_sys_close_range+0x7a/0x90 fs/open.c:1594
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f846f18ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffda256b568 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: ffffffffffffffda RBX: 000000000002ea3b RCX: 00007f846f18ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000001 R09: 00000002a256b85f
R10: 0000001b2cc20000 R11: 0000000000000246 R12: 00007f846f3b5fac
R13: 00007f846f3b5fa0 R14: ffffffffffffffff R15: 0000000000000005
 </TASK>