rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (2 ticks this GP) idle=27e4/1/0x4000000000000000 softirq=15480/15480 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6013/1:b..l P5821/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=8117, q=119 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6015 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__lock_acquire+0x7c/0x1c90 kernel/locking/lockdep.c:5103
Code: e1 03 00 00 44 8b 1d b3 8d 93 0c 89 f3 41 89 d6 45 85 db 74 61 48 3d 50 45 a8 93 74 59 44 8b 2d 7a 4c 18 19 45 85 ed 0f 94 c0 <41> 89 c4 83 fb 07 76 08 84 c0 0f 85 65 08 00 00 83 fb 01 76 40 31
RSP: 0018:ffffc90000007bc8 EFLAGS: 00000046
RAX: ffffffff9aca6401 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff9ad71750
RBP: ffff8880796a0000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff9ad71750
FS: 00007f6b21cfc6c0(0000) GS:ffff888124a08000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001480 CR3: 0000000069051000 CR4: 00000000003526f0
Call Trace:
lock_acquire kernel/locking/lockdep.c:5868 [inline]
lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5825
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
debug_object_activate+0x14c/0x4c0 lib/debugobjects.c:818
debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
debug_activate kernel/time/hrtimer.c:477 [inline]
enqueue_hrtimer+0x23/0x3b0 kernel/time/hrtimer.c:1081
__run_hrtimer kernel/time/hrtimer.c:1794 [inline]
__hrtimer_run_queues+0x8ff/0xad0 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 26 78 35 f6 48 89 df e8 0e cc 35 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 35 d4 25 f6 65 8b 05 7e 35 3e 08 85 c0 74 16 5b
RSP: 0018:ffffc900034d7170 EFLAGS: 00000246
RAX: 0000000000000006 RBX: ffff88807bf7d2e8 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff8da2b882 RDI: ffffffff8bf07040
RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90820dd7 R11: 0000000000000001 R12: ffff88807bf7d0f0
R13: 0000000000000000 R14: 1877619662e4cdd8 R15: 0000000000000002
spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
taprio_change+0x28ae/0x3a70 net/sched/sch_taprio.c:1985
taprio_init+0x690/0x910 net/sched/sch_taprio.c:2125
qdisc_create+0x457/0xfc0 net/sched/sch_api.c:1319
__tc_modify_qdisc net/sched/sch_api.c:1748 [inline]
tc_modify_qdisc+0x11d8/0x2170 net/sched/sch_api.c:1812
rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6960
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6b20d8f6c9
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:00007f6b21cfc038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f6b20fe5fa0 RCX: 00007f6b20d8f6c9
RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000004
RBP: 00007f6b20e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6b20fe6038 R14: 00007f6b20fe5fa0 R15: 00007ffc064f1638
task:udevd state:R running task stack:25768 pid:5821 tgid:5821 ppid:5184 task_flags:0x400140 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7206
preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13
rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:752
rcu_read_unlock include/linux/rcupdate.h:895 [inline]
class_rcu_destructor include/linux/rcupdate.h:1195 [inline]
unwind_next_frame+0xa86/0x20a0 arch/x86/kernel/unwind_orc.c:479
__unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_save_track+0x14/0x30 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:417
kasan_kmalloc include/linux/kasan.h:262 [inline]
__do_kmalloc_node mm/slub.c:5650 [inline]
__kmalloc_noprof+0x32f/0x880 mm/slub.c:5662
kmalloc_noprof include/linux/slab.h:961 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45
tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80
tomoyo_realpath_from_path+0x18f/0x6e0 security/tomoyo/realpath.c:283
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x274/0x460 security/tomoyo/file.c:822
tomoyo_path_symlink+0x97/0xe0 security/tomoyo/tomoyo.c:212
security_path_symlink+0x152/0x2e0 security/security.c:2023
do_symlinkat+0x10d/0x310 fs/namei.c:4841
__do_sys_symlink fs/namei.c:4864 [inline]
__se_sys_symlink fs/namei.c:4862 [inline]
__x64_sys_symlink+0x75/0x90 fs/namei.c:4862
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ffba8f15527
RSP: 002b:00007ffde92f4fd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000058
RAX: ffffffffffffffda RBX: 000055b6e3435490 RCX: 00007ffba8f15527
RDX: fffffffffffffe68 RSI: 00007ffde92f4fe0 RDI: 000055b6e3223a60
RBP: 000000000000004e R08: 0000000000000064 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffde92f4fe0
R13: 000055b6e32128d0 R14: 0000000000000008 R15: 000055b6e3435490
task:sed state:R running task stack:25912 pid:6013 tgid:6013 ppid:6012 task_flags:0x40000c flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7256
irqentry_exit+0x36/0x90 kernel/entry/common.c:211
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x350 kernel/locking/lockdep.c:5872
Code: b6 08 12 83 f8 07 0f 87 bc 02 00 00 89 c0 48 0f a3 05 22 44 e9 0e 0f 82 74 02 00 00 8b 35 9a 74 e9 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 39 b6 08 12 0f 85 c7 02 00 00 48 83 c4
RSP: 0018:ffffc900032f7720 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c4720 RCX: 00000000dbfb52df
RDX: 0000000000000000 RSI: ffffffff8da05e9c RDI: ffffffff8bf07040
RBP: 0000000000000002 R08: 11edc8a8be3b5a24 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
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+0xd1/0x20a0 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:559
slab_free_hook mm/slub.c:2504 [inline]
slab_free mm/slub.c:6638 [inline]
kmem_cache_free+0x15e/0x6c0 mm/slub.c:6748
exit_mmap+0x50a/0xb90 mm/mmap.c:1305
__mmput+0x12a/0x410 kernel/fork.c:1133
mmput+0x62/0x70 kernel/fork.c:1156
exit_mm kernel/exit.c:582 [inline]
do_exit+0x7c7/0x2bf0 kernel/exit.c:954
do_group_exit+0xd3/0x2a0 kernel/exit.c:1107
__do_sys_exit_group kernel/exit.c:1118 [inline]
__se_sys_exit_group kernel/exit.c:1116 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1116
x64_sys_call+0x150b/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc2a403c6c5
RSP: 002b:00007ffd078b8408 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fc2a413dfe8 RCX: 00007fc2a403c6c5
RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fc2a413c680 R15: 00007fc2a413e000
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g8117 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=0 timer-softirq=4383
rcu: rcu_preempt kthread starved for 10502 jiffies! g8117 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:28440 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x1190/0x5de0 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:7026
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x675/0x7d0 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245