rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6494/1:b..l P13/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=35621, q=152 ncpus=2)
task:kworker/u8:1 state:R running task stack:21432 pid:13 tgid:13 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x0/0x3e0 kernel/locking/lockdep.c:5876
Code: de e8 b4 ed 63 03 48 8b 3c 24 e9 08 fa ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 30 49 89 f5 49
RSP: 0018:ffffc90000127988 EFLAGS: 00000293
RAX: ffffffff8b4cca9c RBX: ffffffff8b4ccf20 RCX: ffff88801d2b0000
RDX: 0000000000000000 RSI: ffffffff8b4cc8da RDI: ffffffff8e33cf20
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8b4cc8da
R10: dffffc0000000000 R11: fffffbfff1f87dc7 R12: dffffc0000000000
R13: ffff8880339a98b0 R14: 000000000000004a R15: ffff8880339a8d80
rcu_lock_release include/linux/rcupdate.h:341 [inline]
rcu_read_unlock include/linux/rcupdate.h:871 [inline]
batadv_nc_process_nc_paths+0x2f9/0x3a0 net/batman-adv/network-coding.c:699
batadv_nc_worker+0x52b/0x610 net/batman-adv/network-coding.c:735
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:udevd state:R running task stack:22376 pid:6494 tgid:6494 ppid:5233 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:rcu_is_watching+0x6f/0xb0 kernel/rcu/tree.c:753
Code: c7 c3 98 9f c3 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 09 0d 1b 11 74 11 83 e0 04 c1 e8 02 <5b> 41 5e 41 5f c3 cc cc cc cc cc e8 91 74 8c ff eb e8 48 c7 c7 00
RSP: 0018:ffffc9000db8f818 EFLAGS: 00000202
RAX: 0000000000000001 RBX: ffff8880b8732f98 RCX: 6f9a7fd63db50800
RDX: 0000000000000000 RSI: ffffffff8c0371e0 RDI: ffffffff8c0371a0
RBP: ffffffff8173bcb5 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000db8f9f8 R11: ffffffff81ad3e20 R12: 0000000000000002
R13: ffffffff8e33cf20 R14: ffffffff8dde6dd8 R15: dffffc0000000000
trace_lock_acquire include/trace/events/lock.h:24 [inline]
lock_acquire+0x5f/0x360 kernel/locking/lockdep.c:5831
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [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 mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5b/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2484 [inline]
slab_free mm/slub.c:6121 [inline]
kmem_cache_free+0x19a/0x690 mm/slub.c:6232
do_sys_openat2+0x154/0x1c0 fs/open.c:1443
do_sys_open fs/open.c:1450 [inline]
__do_sys_openat fs/open.c:1466 [inline]
__se_sys_openat fs/open.c:1461 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1461
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: 0033:0x7fe82eaa7407
RSP: 002b:00007fff24773080 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe82f163880 RCX: 00007fe82eaa7407
RDX: 00000000000a0241 RSI: 00007fff24773d40 RDI: ffffffffffffff9c
RBP: 0000562589816040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000124 R11: 0000000000000202 R12: 00005625897c1ba0
R13: 00007fff24773d40 R14: 00007fff24773940 R15: 00007fff24773540
rcu: rcu_preempt kthread timer wakeup didn't happen for 10452 jiffies! g35621 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=31342
rcu: rcu_preempt kthread starved for 10458 jiffies! g35621 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:27256 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7046 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7061
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+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 1302 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 eb 09 47 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 d3 a3 0f f6 65 8b 05 5c 08 41 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc90003e97660 EFLAGS: 00000206
RAX: e5bccee19c78bf00 RBX: 0000000000000a06 RCX: e5bccee19c78bf00
RDX: 0000000000000002 RSI: ffffffff8dbbd436 RDI: 0000000000000001
RBP: ffffc90003e976e8 R08: ffffffff8fc3ee37 R09: 1ffffffff1f87dc6
R10: dffffc0000000000 R11: fffffbfff1f87dc7 R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff9a02fb40 R15: 1ffff920007d2ecc
FS: 0000000000000000(0000) GS:ffff8881259f9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b33bfeff8 CR3: 000000007fa68000 CR4: 00000000003526f0
Call Trace:
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+0xc9/0x130 drivers/tty/serial/serial_core.c:626
handle_tx+0x23f/0x610 drivers/net/caif/caif_serial.c:222
__netdev_start_xmit include/linux/netdevice.h:5222 [inline]
netdev_start_xmit include/linux/netdevice.h:5231 [inline]
xmit_one net/core/dev.c:3839 [inline]
dev_hard_start_xmit+0x2d4/0x830 net/core/dev.c:3855
__dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4725
dev_queue_xmit include/linux/netdevice.h:3361 [inline]
tx+0x6b/0x190 drivers/block/aoe/aoenet.c:62
kthread+0x1cd/0x3e0 drivers/block/aoe/aoecmd.c:1241
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245