rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4977/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=33701, q=990 ncpus=2)
task:udevd state:R running task stack:25816 pid:4977 tgid:4977 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7188
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7512
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872
Code: 05 fb fd 25 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 06 15 f3 0e 0f 82 a4 02 00 00 8b 35 8e 48 f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 9d fd 25 12 0f 85 ed 02 00 00 48 83 c4
RSP: 0018:ffffc90004ec7910 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000004
RDX: 0000000000000000 RSI: ffffffff8def8e2a RDI: ffffffff8c1c3200
RBP: ffffffff8e7e54e0 R08: 00000000e8a865ce R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
netlink_deliver_tap+0x132/0xcc0 net/netlink/af_netlink.c:335
__netlink_sendskb net/netlink/af_netlink.c:1260 [inline]
netlink_broadcast_deliver net/netlink/af_netlink.c:1399 [inline]
do_one_broadcast net/netlink/af_netlink.c:1488 [inline]
netlink_broadcast_filtered+0x914/0xe90 net/netlink/af_netlink.c:1533
netlink_broadcast+0x39/0x50 net/netlink/af_netlink.c:1557
uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline]
kobject_uevent_net_broadcast lib/kobject_uevent.c:410 [inline]
kobject_uevent_env+0xcdd/0x18b0 lib/kobject_uevent.c:611
kobject_synth_uevent+0x6f0/0x7d0 lib/kobject_uevent.c:207
uevent_store+0x24/0x50 drivers/base/core.c:2773
dev_attr_store+0x58/0x80 drivers/base/core.c:2437
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:142
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:352
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1070 fs/read_write.c:688
ksys_write+0x12a/0x250 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb7c0a7407
RSP: 002b:00007ffd2a2b1370 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbb7c7d1880 RCX: 00007fbb7c0a7407
RDX: 0000000000000007 RSI: 000055ade49962b0 RDI: 000000000000000c
RBP: 000055ade49962b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000007
R13: 000055ade46eecf0 R14: 00007fbb7c1efea0 R15: 00007ffd2a2b16e0
rcu: rcu_preempt kthread starved for 10509 jiffies! g33701 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:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5387 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7188
__schedule_loop kernel/sched/core.c:7267 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7282
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 15154 Comm: iou-sqp-15153 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217
Code: 01 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 d1 4b 84 09 8b 82 cc 16 00 00 85 c0 74 f1 8b 82 a8 16 00 00 <83> f8 02 75 e6 48 8b 8a b0 16 00 00 8b 92 ac 16 00 00 48 8b 01 48
RSP: 0018:ffffc90005637ca0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff84f15dce
RDX: ffff88807ce20000 RSI: ffffffff84f15a45 RDI: ffff88807ce20000
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88807ba09890
R13: ffff88807ce20000 R14: dffffc0000000000 R15: ffff88807ba093b8
FS: 00007feda49bc6c0(0000) GS:ffff888124479000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000100 CR3: 000000002ba46000 CR4: 00000000003526f0
Call Trace:
io_sq_thread+0x4d5/0x13e0 io_uring/sqpoll.c:344
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245