rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4175/1:b..l
(detected by 1, t=10502 jiffies, g=11501, q=29)
task:udevd state:R running task stack:25600 pid: 4175 ppid: 3559 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
_raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:419 [inline]
__wake_up_common_lock kernel/sched/wait.c:140 [inline]
__wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:205
sock_def_readable+0x136/0x250 net/core/sock.c:3098
unix_dgram_sendmsg+0x11ed/0x1890 net/unix/af_unix.c:1946
sock_sendmsg_nosec net/socket.c:706 [inline]
__sock_sendmsg net/socket.c:718 [inline]
sock_write_iter+0x29c/0x380 net/socket.c:1089
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x712/0xd00 fs/read_write.c:594
ksys_write+0x14d/0x250 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f04d232c407
RSP: 002b:00007ffc94016f40 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f04d223e880 RCX: 00007f04d232c407
RDX: 0000000000000000 RSI: 00007ffc94016fe7 RDI: 000000000000000a
RBP: 000000000000000a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007f04d223e6e8
R13: 0000000000000000 R14: 0000000000000000 R15: 000055ec19a07f10
rcu: rcu_preempt kthread timer wakeup didn't happen for 10527 jiffies! g11501 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=8296
rcu: rcu_preempt kthread starved for 10533 jiffies! g11501 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:27808 pid: 15 ppid: 2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
schedule+0x11b/0x1e0 kernel/sched/core.c:6478
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
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: 4176 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:__lock_acquire+0x12e1/0x7c60 kernel/locking/lockdep.c:5009
Code: 07 89 c3 81 e3 ff 1f 00 00 c1 e8 03 25 f8 03 00 00 48 8d b8 c0 e0 fb 8f be 08 00 00 00 e8 c7 23 60 00 48 0f a3 1d bf ce 9f 0e <73> 1a 48 8d 04 5b c1 e0 06 48 8d 98 80 5f 94 8f 49 b8 00 00 00 00
RSP: 0018:ffffc90002e9f140 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 000000000000020c RCX: ffffffff815c11f9
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbe100
RBP: ffffc90002e9f390 R08: dffffc0000000000 R09: fffffbfff1ff7c21
R10: fffffbfff1ff7c21 R11: 1ffffffff1ff7c20 R12: 000000009ad61b2d
R13: ffff88807a2d5940 R14: 000000004651107c R15: ffff88807a2d6478
FS: 0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e256efb89 CR3: 0000000071122000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
local_lock_acquire+0x34/0x170 include/linux/local_lock_internal.h:29
__lru_cache_activate_page mm/swap.c:367 [inline]
mark_page_accessed+0x4c3/0x12b0 mm/swap.c:424
zap_pte_range mm/memory.c:1381 [inline]
zap_pmd_range mm/memory.c:1505 [inline]
zap_pud_range mm/memory.c:1534 [inline]
zap_p4d_range mm/memory.c:1555 [inline]
unmap_page_range+0xe10/0x2520 mm/memory.c:1576
unmap_vmas+0x11b/0x230 mm/memory.c:1653
exit_mmap+0x38f/0x5f0 mm/mmap.c:3216
__mmput+0x115/0x3b0 kernel/fork.c:1127
exit_mm+0x567/0x6c0 kernel/exit.c:550
do_exit+0x5a1/0x20a0 kernel/exit.c:870
do_group_exit+0x12e/0x300 kernel/exit.c:997
get_signal+0x6ca/0x12c0 kernel/signal.c:2900
arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867
handle_signal_work kernel/entry/common.c:154 [inline]
exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
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: 0033:0x7f86b65527d3
Code: Unable to access opcode bytes at RIP 0x7f86b65527a9.
RSP: 002b:00007ffcf061a038 EFLAGS: 00000202 ORIG_RAX: 000000000000003d
RAX: fffffffffffffe00 RBX: 000000000000105e RCX: 00007f86b65527d3
RDX: 0000000040000000 RSI: 00007ffcf061a04c RDI: 00000000ffffffff
RBP: 00007ffcf061a04c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000008
R13: 0000000000000003 R14: 00007ffcf061a338 R15: 0000000000000000