rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8681/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=32505, q=741 ncpus=2)
task:udevadm state:R running task stack:24552 pid:8681 tgid:8681 ppid:6342 task_flags:0x400000 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__kasan_check_byte+0x12/0x40 mm/kasan/common.c:579
Code: cf fe ff ff 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 40 d6 41 56 53 48 89 f3 49 89 fe e8 2e 15 00 00 <84> c0 75 16 be 01 00 00 00 4c 89 f7 31 d2 48 89 d9 89 c3 e8 c6 03
RSP: 0018:ffffc900030d7740 EFLAGS: 00000293
RAX: 0000000000000001 RBX: ffffffff8173cd42 RCX: 1db3fb52b8618c00
RDX: 0000000000000000 RSI: ffffffff8173cd42 RDI: 1ffffffff1c27a5c
RBP: ffffffff8173cd25 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc900030d7918 R11: ffffffff81ac6cd0 R12: 0000000000000002
R13: ffffffff8e13d2e0 R14: ffffffff8e13d2e0 R15: 0000000000000000
kasan_check_byte include/linux/kasan.h:401 [inline]
lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5842
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:867 [inline]
class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:559
__call_rcu_common kernel/rcu/tree.c:3123 [inline]
call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3243
slab_free_hook mm/slub.c:2479 [inline]
slab_free mm/slub.c:6574 [inline]
kmem_cache_free+0x4b5/0x690 mm/slub.c:6684
fput_close_sync+0x119/0x200 fs/file_table.c:573
__do_sys_close fs/open.c:1589 [inline]
__se_sys_close fs/open.c:1574 [inline]
__x64_sys_close+0x7f/0x110 fs/open.c:1574
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f270c515a67
RSP: 002b:00007ffd5dd4b8d8 EFLAGS: 00000297 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 000055a7c8abf2a0 RCX: 00007f270c515a67
RDX: 00007f270c5efea0 RSI: 000055a7c8ad1e50 RDI: 0000000000000005
RBP: 00007f270c5efff0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000000
R13: 000055a7c8abf2a0 R14: 00007ffd5dd4b940 R15: 000055a7c8acfe60
rcu: rcu_preempt kthread timer wakeup didn't happen for 10470 jiffies! g32505 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=17620
rcu: rcu_preempt kthread starved for 10471 jiffies! g32505 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 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 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1300 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline]
RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline]
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x5a/0xb0 kernel/rcu/tree.c:751
Code: f0 48 c1 e8 03 42 80 3c 38 00 74 08 4c 89 f7 e8 6c 66 7f 00 48 c7 c3 d8 7f 92 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 <84> c0 75 34 8b 03 65 ff 0d f9 c1 ea 10 74 11 83 e0 04 c1 e8 02 5b
RSP: 0018:ffffc900043af620 EFLAGS: 00000802
RAX: 0000000000000000 RBX: ffff8880b8632fd8 RCX: a912ed6c39442d00
RDX: 0000000000000000 RSI: ffffffff8bc079c0 RDI: ffffffff8bc07980
RBP: ffffc900043af6e8 R08: ffffffff8f9e1877 R09: 1ffffffff1f3c30e
R10: dffffc0000000000 R11: fffffbfff1f3c30f R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff8da0bdd0 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888125d0b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2aef38afe0 CR3: 00000000539f2000 CR4: 00000000003526f0
Call Trace:
trace_irq_enable+0x37/0x110 include/trace/events/preemptirq.h:40
trace_hardirqs_on+0x18/0x40 kernel/trace/trace_preemptirq.c:73
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x85/0x110 kernel/locking/spinlock.c:194
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
uart_port_unlock_deref+0x111/0x2f0 drivers/tty/serial/serial_core.c:91
uart_write_room+0xe4/0x170 drivers/tty/serial/serial_core.c:647
handle_tx+0x163/0x610 drivers/net/caif/caif_serial.c:212
__netdev_start_xmit include/linux/netdevice.h:5259 [inline]
netdev_start_xmit include/linux/netdevice.h:5268 [inline]
xmit_one net/core/dev.c:3845 [inline]
dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3861
__dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4763
dev_queue_xmit include/linux/netdevice.h:3368 [inline]
tx+0x6b/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1d0/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245