rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5929/1:b..l
rcu: (detected by 1, t=10503 jiffies, g=12953, q=706 ncpus=2)
task:udevd state:R running task stack:25224 pid:5929 ppid:5141 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
_raw_spin_unlock_irqrestore+0x111/0x120 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x12c/0x1a0 kernel/sched/wait.c:213
sock_def_readable+0x1e1/0x420 net/core/sock.c:3354
unix_dgram_sendmsg+0x106c/0x16d0 net/unix/af_unix.c:2141
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
sock_write_iter+0x2df/0x420 net/socket.c:1160
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x46c/0x990 fs/read_write.c:584
ksys_write+0x150/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe83daa7407
RSP: 002b:00007ffc6ef8b950 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe83e151880 RCX: 00007fe83daa7407
RDX: 0000000000000000 RSI: 00007ffc6ef8b9f7 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fe83e1516e8
R13: 0000000000000000 R14: 0000000000000000 R15: 00005596560f4b20
rcu: rcu_preempt kthread starved for 10531 jiffies! g12953 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:27656 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 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
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: 6029 Comm: syz.2.54 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:timerqueue_del+0x30/0x100 lib/timerqueue.c:55
Code: 57 41 56 41 55 41 54 53 49 89 f6 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 ad a4 11 f7 4c 89 f5 48 c1 ed 03 42 80 7c 2d 00 00 <74> 08 4c 89 f7 e8 86 d3 69 f7 4d 8b 3e 4c 89 ff 4c 89 f6 e8 98 a6
RSP: 0018:ffffc90000007d08 EFLAGS: 00000046
RAX: ffffffff8a7577b3 RBX: ffff8880b8e2b850 RCX: ffff88802b749e00
RDX: 0000000000010000 RSI: ffff88802eb61830 RDI: ffff8880b8e2b850
RBP: 1ffff11005d6c306 R08: ffffffff97569a83 R09: 1ffffffff2ead350
R10: dffffc0000000000 R11: fffffbfff2ead351 R12: ffff88802eb61830
R13: dffffc0000000000 R14: ffff88802eb61830 R15: 0000000000000001
FS: 00007f848dd376c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 000000005c332000 CR4: 00000000003506f0
Call Trace:
__remove_hrtimer kernel/time/hrtimer.c:1141 [inline]
__run_hrtimer kernel/time/hrtimer.c:1730 [inline]
__hrtimer_run_queues+0x37f/0xc40 kernel/time/hrtimer.c:1814
hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
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+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90003a87a60 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 329952e026a74300
RDX: 0000000000000000 RSI: ffffffff8acadae0 RDI: ffffffff8b1c85a0
RBP: ffffc90003a87b68 R08: dffffc0000000000 R09: 1ffffffff22382a6
R10: dffffc0000000000 R11: fffffbfff22382a7 R12: 1ffff92000750f58
R13: ffff888078aec420 R14: 0000000000000246 R15: dffffc0000000000
__might_fault+0xc6/0x120 mm/memory.c:5968
_copy_to_user+0x2a/0xa0 lib/usercopy.c:36
copy_to_user include/linux/uaccess.h:191 [inline]
copy_siginfo_to_user+0x24/0xa0 kernel/signal.c:3372
x64_setup_rt_frame+0x746/0xc40 arch/x86/kernel/signal_64.c:194
setup_rt_frame arch/x86/kernel/signal.c:223 [inline]
handle_signal arch/x86/kernel/signal.c:267 [inline]
arch_do_signal_or_restart+0x42c/0x800 arch/x86/kernel/signal.c:312
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xee/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+0x61/0xa0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f848cd9c797
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:00007f848dd370e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f848d015fa8 RCX: 00007f848cd9c799
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f848d015fa8
RBP: 00007f848d015fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f848d016038 R14: 00007ffc350e0780 R15: 00007ffc350e0868
sched: RT throttling activated