syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (10402 ticks this GP) idle=262c/1/0x4000000000000000 softirq=15859/15880 fqs=60
rcu: 	         hardirqs   softirqs   csw/system
rcu: 	 number:  1968506        281            0
rcu: 	cputime:    37702      11078           16   ==> 48820(ms)
rcu: 	(t=10504 jiffies g=15145 q=824 ncpus=2)
rcu: rcu_preempt kthread starved for 318 jiffies! g15145 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:26632 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 6506 Comm: syz.0.180 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:hlist_empty include/linux/list.h:972 [inline]
RIP: 0010:perf_trace_lock+0x159/0x380 include/trace/events/lock.h:50
Code: 10 48 03 0b 48 89 4c 24 10 42 80 3c 20 00 74 08 4c 89 f7 e8 29 cf 76 00 49 83 3e 00 75 25 48 8b 5c 24 10 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 74 08 48 89 df e8 08 cf 76 00 48 83 3b 00 0f 84 7f
RSP: 0018:ffffc90000007860 EFLAGS: 00000806
RAX: 1ffffd1ffff8448e RBX: ffffe8ffffc22470 RCX: ffffe8ffffc22470
RDX: ffffffff8175af07 RSI: ffffffff8afc6f60 RDI: ffffffff8afc6f20
RBP: ffffc90000007950 R08: ffffffff8e4a212f R09: 1ffffffff1c94425
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: dffffc0000000000
R13: 0000000000000012 R14: ffffffff8cbfb270 R15: ffffffff8cbfb200
FS:  00007fbb0d9636c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000030e77000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 trace_lock_release include/trace/events/lock.h:69 [inline]
 lock_release+0x857/0x8b0 kernel/locking/lockdep.c:5765
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline]
 _raw_spin_unlock_irqrestore+0x71/0x110 kernel/locking/spinlock.c:194
 hrtimer_interrupt+0x597/0x9c0 kernel/time/hrtimer.c:1886
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x51/0xc0 arch/x86/kernel/apic/apic.c:1088
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:tasklet_unlock kernel/softirq.c:911 [inline]
RIP: 0010:tasklet_action_common+0x405/0x4c0 kernel/softirq.c:817
Code: df e8 ff 49 8b 00 49 8b 77 18 4c 89 ff e8 c3 01 00 00 44 8b 6c 24 14 4c 89 e7 be 08 00 00 00 e8 c1 4b 8b 00 f0 41 80 24 24 fd <4c> 89 e7 e8 f3 a2 12 00 49 bc 00 00 00 00 00 fc ff df e9 1a fd ff
RSP: 0018:ffffc90000007d40 EFLAGS: 00000246
RAX: 0000000000000001 RBX: ffff88807dfc1600 RCX: ffffffff8151b4cf
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffff88807dfc15f0
RBP: ffffc90000007e30 R08: ffff88807dfc15f7 R09: 1ffff1100fbf82be
R10: dffffc0000000000 R11: ffffed100fbf82bf R12: ffff88807dfc15f0
R13: 0000000000000006 R14: 0000000000000000 R15: ffff88807dfc15e8
 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:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 cc 01 00 00 49 ff c3 48 ff c3 75 ee e9 21 01 00 00 44 89 dd
RSP: 0018:ffffc9000ba37060 EFLAGS: 00000246
RAX: 1ffff11004e4eb01 RBX: ffffffffffffffff RCX: ffffffff815c504a
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff88801fbd4280
RBP: ffffc9000ba370f0 R08: ffff88801fbd4283 R09: 1ffff11003f7a850
R10: dffffc0000000000 R11: ffffed1003f7a850 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffed1003f7a851 R15: 1ffff11003f7a850
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_dec_and_test include/linux/atomic/atomic-instrumented.h:1375 [inline]
 mmdrop include/linux/sched/mm.h:53 [inline]
 mmdrop_sched include/linux/sched/mm.h:82 [inline]
 mmdrop_lazy_tlb_sched include/linux/sched/mm.h:109 [inline]
 finish_task_switch+0x32a/0x920 kernel/sched/core.c:5279
 context_switch kernel/sched/core.c:5383 [inline]
 __schedule+0x14da/0x44d0 kernel/sched/core.c:6699
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:sort+0x4/0xf0 lib/sort.c:284
Code: ff e8 c0 cd 69 fd 48 81 c4 78 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa <55> 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 80 00
RSP: 0018:ffffc9000ba37468 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff819917a0
RDX: 0000000000000010 RSI: 0000000000000001 RDI: ffff88801d778a90
RBP: 0000000000000001 R08: 0000000000000000 R09: 000000008fafad79
R10: dffffc0000000000 R11: fffffbfff1c94426 R12: ffff88801d778a90
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff88801d778a90
 add_subprog+0x2b8/0x3c0 kernel/bpf/verifier.c:2690
 add_subprog_and_kfunc kernel/bpf/verifier.c:3044 [inline]
 bpf_check+0xae9/0xe970 kernel/bpf/verifier.c:20406
 bpf_prog_load+0x11cb/0x16d0 kernel/bpf/syscall.c:2750
 __sys_bpf+0x55a/0x800 kernel/bpf/syscall.c:5473
 __do_sys_bpf kernel/bpf/syscall.c:5577 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5575 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5575
 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: 0033:0x7fbb0cb8f749
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:00007fbb0d963038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fbb0cde5fa0 RCX: 00007fbb0cb8f749
RDX: 0000000000000094 RSI: 0000200000000040 RDI: 0000000000000005
RBP: 00007fbb0cc13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb0cde6038 R14: 00007fbb0cde5fa0 R15: 00007ffd281c0f28
 </TASK>
CPU: 1 PID: 6501 Comm: syz.2.178 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_read_unlock_special+0x88/0x460 kernel/rcu/tree_plugin.h:698
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 69 4f 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001f0b20 EFLAGS: 00000206
RAX: 59dbef8d120ee700 RBX: 1ffff9200003e168 RCX: 59dbef8d120ee700
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: ffffc900001f0c00 R08: ffffffff90d945ff R09: 1ffffffff21b28bf
R10: dffffc0000000000 R11: fffffbfff21b28c0 R12: ffffffff8cd35101
R13: dffffc0000000000 R14: 0000000000000246 R15: ffff88807ece1e00
FS:  00007faaf05946c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000060452000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <IRQ>
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 ieee80211_rx_napi+0x21d/0x3c0 net/mac80211/rx.c:5456
 ieee80211_rx include/net/mac80211.h:4971 [inline]
 ieee80211_handle_queued_frames+0x106/0x1a0 net/mac80211/main.c:319
 tasklet_action_common+0x2eb/0x4c0 kernel/softirq.c:809
 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:rcu_read_unlock_special+0x88/0x460 kernel/rcu/tree_plugin.h:698
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 69 4f 93 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc9000b7d7540 EFLAGS: 00000206
RAX: 59dbef8d120ee700 RBX: 1ffff920016faeac RCX: 59dbef8d120ee700
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: ffffffff8afc6f80
RBP: ffffc9000b7d7620 R08: ffffffff90d945ff R09: 1ffffffff21b28bf
R10: dffffc0000000000 R11: fffffbfff21b28c0 R12: ffffffff8cd35101
R13: dffffc0000000000 R14: 0000000000000246 R15: ffff88807ece1e00
 __rcu_read_unlock+0x7c/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:818 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2323 [inline]
 bpf_trace_run2+0x25e/0x3c0 kernel/trace/bpf_trace.c:2361
 __bpf_trace_contention_begin+0xdd/0x130 include/trace/events/lock.h:95
 trace_contention_begin+0xc5/0xe0 include/trace/events/lock.h:95
 __mutex_lock_common kernel/locking/mutex.c:605 [inline]
 __mutex_lock+0x13a/0xcc0 kernel/locking/mutex.c:747
 perf_event_exit_task_context kernel/events/core.c:13265 [inline]
 perf_event_exit_task+0x280/0x870 kernel/events/core.c:13329
 do_exit+0x889/0x23c0 kernel/exit.c:868
 do_group_exit+0x21b/0x2d0 kernel/exit.c:1024
 get_signal+0x12fc/0x1400 kernel/signal.c:2902
 arch_do_signal_or_restart+0x9c/0x7b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7faaef78f749
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:00007faaf0594038 EFLAGS: 00000246 ORIG_RAX: 000000000000012a
RAX: 0000000000000013 RBX: 00007faaef9e6180 RCX: 00007faaef78f749
RDX: ffffffffffffffff RSI: 0000000000000000 RDI: 0000200000000180
RBP: 00007faaef813f91 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 0000000000000000
R13: 00007faaef9e6218 R14: 00007faaef9e6180 R15: 00007ffd27a3f728
 </TASK>