rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5206/1:b..l rcu: (detected by 1, t=10502 jiffies, g=30033, q=736 ncpus=2) task:udevd state:R running task stack:22952 pid:5206 tgid:5206 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5896 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 cb aa fe 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc900033a6fb0 EFLAGS: 00000206 RAX: dab6c326d1f7fd00 RBX: 0000000000000202 RCX: dab6c326d1f7fd00 RDX: 0000000000000001 RSI: ffffffff8db6ecc6 RDI: ffffffff8be28a80 RBP: ffff88807ec74718 R08: ffffc900033a71d0 R09: 0000000000000000 R10: ffffc900033a7198 R11: fffff52000674e35 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8e13ed60 R15: ffff88807ec73c00 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4328 [inline] __kmalloc_noprof+0x27a/0x4f0 mm/slub.c:4340 kmalloc_noprof include/linux/slab.h:909 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_check_open_permission+0x1c1/0x3b0 security/tomoyo/file.c:771 security_file_open+0xb1/0x270 security/security.c:3114 do_dentry_open+0x35e/0x1970 fs/open.c:941 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:3887 [inline] path_openat+0x2ee5/0x3830 fs/namei.c:4046 do_filp_open+0x1fa/0x410 fs/namei.c:4073 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5ecc4a7407 RSP: 002b:00007fff48915c60 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f5eccc97880 RCX: 00007f5ecc4a7407 RDX: 0000000000080141 RSI: 0000557d46ec602e RDI: ffffffffffffff9c RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10546 jiffies! g30033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=11239 rcu: rcu_preempt kthread starved for 10547 jiffies! g30033 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27320 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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: 1 UID: 0 PID: 3082 Comm: kworker/1:2 Not tainted 6.16.0-rc1-syzkaller-00236-g8c6bc74c7f89 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: mld mld_ifc_work RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_cmp8+0x11/0x90 kernel/kcov.c:294 Code: 09 cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 f0 9c 92 <65> 8b 15 78 91 dc 10 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 RSP: 0018:ffffc9000b3c70d8 EFLAGS: 00000202 RAX: ffffffff8985d0d5 RBX: ffff888024c76d58 RCX: ffff88802f758000 RDX: 0000000000000000 RSI: 18496c2aa7f86190 RDI: 18496c2aa7f90d8f RBP: ffffc9000b3c7250 R08: ffff888034aa12e7 R09: 1ffff1100695425c R10: dffffc0000000000 R11: ffffed100695425d R12: 18496c2aa7f86190 R13: 18496c2aa7f90d8f R14: 18496c2aa7f7e18f R15: 1ffff1100498edab FS: 0000000000000000(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1eb55a5f98 CR3: 00000000683ae000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ktime_after include/linux/ktime.h:111 [inline] get_packet_txtime net/sched/sch_taprio.c:523 [inline] taprio_enqueue_one+0xae5/0x1650 net/sched/sch_taprio.c:566 dev_qdisc_enqueue+0x4e/0x260 net/core/dev.c:4068 __dev_xmit_skb net/core/dev.c:4164 [inline] __dev_queue_xmit+0xe0e/0x3a70 net/core/dev.c:4679 neigh_output include/net/neighbour.h:539 [inline] ip6_finish_output2+0x11fb/0x16a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline] ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:226 NF_HOOK+0x9e/0x380 include/linux/netfilter.h:317 mld_sendpack+0x800/0xd80 net/ipv6/mcast.c:1868 mld_send_cr net/ipv6/mcast.c:2169 [inline] mld_ifc_work+0x835/0xde0 net/ipv6/mcast.c:2702 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245