rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4732/1:b..l P7099/1:b..l
(detected by 1, t=10502 jiffies, g=44697, q=141 ncpus=2)
task:udevd state:R running task stack:23648 pid:7099 ppid:3638 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
lockref_get_not_dead+0x72/0xb0 lib/lockref.c:190
__legitimize_path fs/namei.c:708 [inline]
legitimize_path fs/namei.c:718 [inline]
try_to_unlazy+0x125/0x5a0 fs/namei.c:779
complete_walk+0x113/0x350 fs/namei.c:888
path_parentat fs/namei.c:2528 [inline]
__filename_parentat+0x221/0x610 fs/namei.c:2550
filename_parentat fs/namei.c:2568 [inline]
do_unlinkat+0xe5/0x560 fs/namei.c:4361
__do_sys_unlink fs/namei.c:4438 [inline]
__se_sys_unlink fs/namei.c:4436 [inline]
__x64_sys_unlink+0x45/0x50 fs/namei.c:4436
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdd9e915937
RSP: 002b:00007fff48517cd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 000055d5740c8960 RCX: 00007fdd9e915937
RDX: 0000000000000000 RSI: 00007fff48516c90 RDI: 00007fff48517ce0
RBP: 000000000000055a R08: 0000000000000064 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff48517ce0
R13: 000055d5740a8420 R14: 0000000000000008 R15: 000055d5740c8960
task:kworker/u4:17 state:R running task stack:21760 pid:4732 ppid:2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:debug_lockdep_rcu_enabled+0xb/0x30 kernel/rcu/update.c:280
Code: 8c 8a 48 c7 c6 a0 26 8c 8a e8 21 93 36 f7 0f 0b eb d1 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 31 c0 83 3d f7 fd 08 04 00 74 1d <83> 3d 82 31 09 04 00 74 14 65 48 8b 0d 54 17 ec 75 31 c0 83 b9 dc
RSP: 0018:ffffc90005ff7b68 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff89e0c400 RCX: 4b02b5b3b68fc800
RDX: 0000000000000000 RSI: ffffffff8a8c15a0 RDI: ffffffff8adef6a0
RBP: ffff88807de9fb08 R08: dffffc0000000000 R09: fffffbfff215bc49
R10: fffffbfff215bc49 R11: 1ffffffff215bc48 R12: dffffc0000000000
R13: 1ffff1100ad42af3 R14: 0000000000000061 R15: ffff888056a14c80
rcu_read_lock include/linux/rcupdate.h:792 [inline]
batadv_nc_process_nc_paths+0xe4/0x390 net/batman-adv/network-coding.c:687
batadv_nc_worker+0x425/0x600 net/batman-adv/network-coding.c:728
process_one_work+0x898/0x1160 kernel/workqueue.c:2292
worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
rcu: rcu_preempt kthread starved for 10548 jiffies! g44697 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:26496 pid:16 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
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: 9066 Comm: syz.9.1065 Not tainted 6.1.148-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_irqs_disabled_flags arch/x86/include/asm/irqflags.h:125 [inline]
RIP: 0010:check_preemption_disabled+0x59/0x110 lib/smp_processor_id.c:19
Code: 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 04 24 00 02 00 00 74 cc 65 4c 8b 3d 36 08 ec 75 41 f6 47 2f 04
RSP: 0018:ffffc9000382f9a8 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8a8c15a0 RDI: ffffffff8adef6a0
RBP: ffffc9000382faf0 R08: dffffc0000000000 R09: fffffbfff215bc4f
R10: fffffbfff215bc4f R11: 1ffffffff215bc4e R12: 0000000000000000
R13: 1ffff92000705f48 R14: 0000000000000246 R15: dffffc0000000000
FS: 00007f446a3976c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3ce104 CR3: 000000002e5fa000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
lock_acquire+0x1c4/0x490 kernel/locking/lockdep.c:5664
__might_fault+0xc2/0x120 mm/memory.c:5852
__copy_from_user include/linux/uaccess.h:75 [inline]
check_xstate_in_sigframe arch/x86/kernel/fpu/signal.c:35 [inline]
__fpu_restore_sig arch/x86/kernel/fpu/signal.c:348 [inline]
fpu__restore_sig+0x203/0x1190 arch/x86/kernel/fpu/signal.c:493
restore_sigcontext arch/x86/kernel/signal.c:140 [inline]
__ia32_sys_rt_sigreturn+0x649/0x790 arch/x86/kernel/signal.c:675
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f446958ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f446a3970e8 EFLAGS: 00000246
RAX: fffffffffffffffc RBX: 00007f44697b6098 RCX: 00007f446958ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f44697b6098
RBP: 00007f44697b6090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f44697b6128 R14: 00007ffecd51fa20 R15: 00007ffecd51fb08