rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3561/1:b..l P4460/1:b..l
(detected by 1, t=10502 jiffies, g=8573, q=217)
task:kworker/u4:9 state:R running task stack:26664 pid: 4460 ppid: 2 flags:0x00004000
Workqueue: bat_events batadv_nc_worker
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:413 [inline]
RIP: 0010:batadv_nc_worker+0x15c/0x5c0 net/batman-adv/network-coding.c:723
Code: be e5 02 00 00 48 c7 c2 20 d1 1f 8b e8 3d 1e 20 00 4c 89 e8 48 c1 e8 03 80 3c 18 00 74 08 4c 89 ef e8 f8 ca 3d f8 4d 8b 6d 00 <4d> 85 ed 0f 94 c0 49 81 c5 38 fe ff ff 0f 94 c1 08 c1 74 07 e8 cb
RSP: 0018:ffffc9000346fbe0 EFLAGS: 00000246
RAX: 1ffff1100f2f2220 RBX: dffffc0000000000 RCX: ffff888020523b80
RDX: 0000000000000000 RSI: ffffffff8a59a4a0 RDI: ffffffff8a59a460
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff1ff7a19
R10: fffffbfff1ff7a19 R11: 1ffffffff1ff7a18 R12: 0000000000000220
R13: 0000000000000000 R14: ffff888078314c80 R15: ffff888017f99550
process_one_work+0x863/0x1000 kernel/workqueue.c:2310
worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
kthread+0x436/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
task:udevd state:R running task stack:23296 pid: 3561 ppid: 1 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5049 [inline]
__schedule+0x11bb/0x4390 kernel/sched/core.c:6395
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6799
irqentry_exit+0x63/0x70 kernel/entry/common.c:432
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:seqcount_lockdep_reader_access+0x17a/0x1c0 include/linux/seqlock.h:106
Code: ff 4d 85 ed 75 16 e8 55 49 ad ff eb 15 e8 4e 49 ad ff e8 89 ad de 07 4d 85 ed 74 ea e8 3f 49 ad ff fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 27 00 00 00 00 66 43 c7 44 27 09 00 00 43 c6 44 27 0b 00
RSP: 0018:ffffc90002e6f700 EFLAGS: 00000293
RAX: ffffffff81ca8111 RBX: 0000000000000000 RCX: ffff88807db83b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002e6f7b0 R08: dffffc0000000000 R09: fffffbfff1ad32b6
R10: fffffbfff1ad32b6 R11: 1ffffffff1ad32b5 R12: dffffc0000000000
R13: 0000000000000200 R14: ffffffff81ca8f82 R15: 1ffff920005cdee0
__follow_mount_rcu fs/namei.c:1457 [inline]
handle_mounts fs/namei.c:1490 [inline]
step_into+0x642/0xd00 fs/namei.c:1806
link_path_walk+0x662/0xd40 fs/namei.c:-1
path_lookupat+0x9d/0x440 fs/namei.c:2454
filename_lookup+0x1e2/0x4f0 fs/namei.c:2484
user_path_at_empty+0x40/0x190 fs/namei.c:2883
user_path_at include/linux/namei.h:57 [inline]
vfs_statx+0x102/0x4d0 fs/stat.c:221
vfs_fstatat fs/stat.c:243 [inline]
__do_sys_newfstatat fs/stat.c:411 [inline]
__se_sys_newfstatat fs/stat.c:405 [inline]
__x64_sys_newfstatat+0x12c/0x1b0 fs/stat.c:405
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: 0033:0x7fbb2122eb0a
RSP: 002b:00007ffc1f04caa8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007ffc1f04cf40 RCX: 00007fbb2122eb0a
RDX: 00007ffc1f04cab0 RSI: 00007ffc1f04cf40 RDI: 00000000ffffff9c
RBP: 0000563277967910 R08: 0000000000000000 R09: 0000000000000040
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc1f04cb40
R13: 00005632658ec100 R14: 0000000000000000 R15: 00007ffc1f04d640
rcu: rcu_preempt kthread starved for 10557 jiffies! g8573 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:27584 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:
NMI backtrace for cpu 1
CPU: 1 PID: 5083 Comm: syz.4.349 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
rcu_pending kernel/rcu/tree.c:3936 [inline]
rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
update_process_times+0x193/0x200 kernel/time/timer.c:1818
tick_sched_handle kernel/time/tick-sched.c:254 [inline]
tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
__run_hrtimer kernel/time/hrtimer.c:1685 [inline]
__hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
__sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:103 [inline]
RIP: 0010:__local_bh_enable_ip+0x132/0x1b0 kernel/softirq.c:408
Code: 8a e8 82 cc 60 08 65 66 8b 05 ca 25 bb 7e 66 85 c0 75 54 bf 01 00 00 00 e8 9b fe 08 00 e8 e6 74 35 00 fb 65 8b 05 76 fc b9 7e <85> c0 75 05 e8 25 07 b8 ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc9000150fa80 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 0000000000000200 RCX: f074587d5dd8de00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: ffffffff8a59a4c0
RBP: ffffc9000150fb10 R08: dffffc0000000000 R09: ffffed1027fd3e41
R10: ffffed1027fd3e41 R11: 1ffff11027fd3e40 R12: ffffffff812bde85
R13: 1ffff11004088a61 R14: dffffc0000000000 R15: 1ffff920002a1f50
fpregs_unlock arch/x86/include/asm/fpu/api.h:78 [inline]
copy_fpstate_to_sigframe+0x7f8/0xb90 arch/x86/kernel/fpu/signal.c:205
get_sigframe arch/x86/kernel/signal.c:295 [inline]
__setup_rt_frame arch/x86/kernel/signal.c:471 [inline]
setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
handle_signal arch/x86/kernel/signal.c:824 [inline]
arch_do_signal_or_restart+0x67a/0x1300 arch/x86/kernel/signal.c:869
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: 0033:0x7f3e643e3ec9
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:00007f3e6264b038 EFLAGS: 00000246
RAX: 000000000000000b RBX: 00007f3e6463afa0 RCX: 00007f3e643e3ec9
RDX: 0000000000000318 RSI: 00002000000bd000 RDI: 0000000000000006
RBP: 00007f3e64466f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3e6463b038 R14: 00007f3e6463afa0 R15: 00007ffd8a663f58