rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5193/1:b..l P7858/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=21665, q=751 ncpus=2)
task:syz.0.672 state:R running task stack:27528 pid:7858 tgid:7858 ppid:6276 task_flags:0x400040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1539/0x5080 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 01 fd 09 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1b 7d 9b 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 40 df 0c 0a cc 48 8d 3d b8 74 94
RSP: 0018:ffffc9000c397b58 EFLAGS: 00000282
RAX: 666bd9ea65cdfe00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 000000005a44979c RSI: ffffffff8e26da84 RDI: ffffffff8c295e00
RBP: ffffffff81b7ee80 R08: ffffffff81b7ee80 R09: ffffffff8e9601a0
R10: ffffc9000c397c40 R11: fffff52001872f8b R12: 0000000000000002
R13: ffffffff8e9601a0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
futex_hash+0x5d/0x2d0 kernel/futex/core.c:308
class_hb_constructor kernel/futex/futex.h:240 [inline]
futex_wake+0x18f/0x580 kernel/futex/waitwake.c:172
do_futex+0x395/0x420 kernel/futex/syscalls.c:135
__do_sys_futex kernel/futex/syscalls.c:207 [inline]
__se_sys_futex+0x3a8/0x450 kernel/futex/syscalls.c:188
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f99ced9aef9
RSP: 002b:00007ffc05ba8e28 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f99ced9aef9
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f99cf005fa8
RBP: 0000000000001c4d R08: 00007ffc05ba8cc7 R09: 0000000000000000
R10: 00007f99cf005fa0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f99cf005fac R14: 00007f99cf005fa8 R15: 00007f99cf005fa0
task:udevd state:R running task stack:25880 pid:5193 tgid:5193 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1539/0x5080 kernel/sched/core.c:6907
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234
irqentry_exit+0x599/0x620 kernel/entry/common.c:239
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x221/0x330 kernel/locking/lockdep.c:5872
Code: ff ff ff e8 01 fd 09 0a f7 44 24 08 00 02 00 00 0f 84 3a ff ff ff 65 48 8b 05 1b 7d 9b 11 48 3b 44 24 58 75 33 fb 48 83 c4 60 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 40 df 0c 0a cc 48 8d 3d b8 74 94
RSP: 0018:ffffc90002fcf358 EFLAGS: 00000282
RAX: e6ee4fb0b3245b00 RBX: 0000000000000000 RCX: 0000000000000046
RDX: 00000000452dbcf7 RSI: ffffffff8e26da84 RDI: ffffffff8c295e00
RBP: ffffffff81768295 R08: ffffffff81768295 R09: ffffffff8e9601a0
R10: ffffc90002fcf4b8 R11: ffffffff81b07be0 R12: 0000000000000002
R13: ffffffff8e9601a0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
rcu_read_lock include/linux/rcupdate.h:850 [inline]
class_rcu_constructor include/linux/rcupdate.h:1193 [inline]
unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4456 [inline]
slab_alloc_node mm/slub.c:4785 [inline]
kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4792
skb_clone+0x212/0x3a0 net/core/skbuff.c:2119
do_one_broadcast net/netlink/af_netlink.c:1455 [inline]
netlink_broadcast_filtered+0x6ae/0x1020 net/netlink/af_netlink.c:1533
netlink_broadcast+0x37/0x50 net/netlink/af_netlink.c:1557
uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
kobject_uevent_net_broadcast+0x378/0x560 lib/kobject_uevent.c:410
kobject_uevent_env+0x55c/0x9e0 lib/kobject_uevent.c:608
kobject_synth_uevent+0x585/0xbd0 lib/kobject_uevent.c:207
uevent_store+0x26/0x70 drivers/base/core.c:2773
kernfs_fop_write_iter+0x3af/0x540 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61d/0xb90 fs/read_write.c:688
ksys_write+0x150/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f84c54a7407
RSP: 002b:00007ffd0ac5c1b0 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f84c5b3f880 RCX: 00007f84c54a7407
RDX: 0000000000000007 RSI: 0000558dd51eda00 RDI: 000000000000000c
RBP: 0000558dd51eda00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007
R13: 0000558dd51f58a0 R14: 00007f84c55efea0 R15: 00007ffd0ac5c570
rcu: rcu_preempt kthread starved for 10497 jiffies! g21665 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:28088 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0x1539/0x5080 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7004
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:467
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 7860 Comm: syz.3.668 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 4a 97 f3 f5 48 89 df e8 b2 0b f4 f5 e8 8d 1e 1f f6 fb bf 01 00 00 00 42 df e5 f5 65 8b 05 ab e5 8e 07 85 c0 74 07 5b e9 d1 47 00 00
RSP: 0000:ffffc9000c48fcc0 EFLAGS: 00000202
RAX: 00000000038bf3a1 RBX: ffff888031662e40 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8dffb921 RDI: 0000000000000001
RBP: 0000000000000021 R08: ffffffff903284b7 R09: 1ffffffff2065096
R10: dffffc0000000000 R11: fffffbfff2065097 R12: 1ffff110062cc65b
R13: 0000000000000000 R14: 000000001c000004 R15: ffff8880316632d8
FS: 00007f81bc0296c0(0000) GS:ffff888125152000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000034d62000 CR4: 00000000003526f0
Call Trace:
spin_unlock_irq include/linux/spinlock.h:401 [inline]
get_signal+0x11a6/0x1330 kernel/signal.c:3037
arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
irqentry_exit+0x176/0x620 kernel/entry/common.c:219
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0033:0x7f81bb19aef7
Code: 83 c8 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
RSP: 002b:00007f81bc0290e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f81bb405fa8 RCX: 00007f81bb19aef9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f81bb405fa8
RBP: 00007f81bb405fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f81bb406038 R14: 00007ffefd0ec7e0 R15: 00007ffefd0ec8c8