rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12709/1:b..l rcu: (detected by 1, t=10503 jiffies, g=103753, q=485 ncpus=2) task:syz-executor state:R running task stack:19496 pid:12709 tgid:12709 ppid:12704 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7193 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline] RIP: 0010:lock_release+0x9c/0x3b0 kernel/locking/lockdep.c:5885 Code: 3c 25 08 40 c4 92 41 83 bf 2c 0b 00 00 00 0f 85 18 02 00 00 49 81 3e c0 03 88 93 0f 84 0b 02 00 00 48 c7 44 24 20 00 00 00 00 <9c> 8f 44 24 20 48 8b 5c 24 20 fa 48 c7 c7 af eb ab 8d e8 7d 80 c8 RSP: 0018:ffffc90003dbf648 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 8008a6480c4e1a00 RDX: 0000000000000000 RSI: ffffffff8be247c0 RDI: ffffffff8be24780 RBP: dffffc0000000000 R08: ffff88801d8a30bf R09: 1ffff11003b14617 R10: dffffc0000000000 R11: ffffed1003b14618 R12: ffffffff82342cda R13: ffffffff82342cda R14: ffffffff8e33f2e0 R15: ffff88801b743d00 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] __page_table_check_zero+0x397/0x3e0 mm/page_table_check.c:145 page_table_check_free include/linux/page_table_check.h:43 [inline] free_pages_prepare mm/page_alloc.c:1407 [inline] __free_frozen_pages+0xbdb/0xd30 mm/page_alloc.c:2943 discard_slab mm/slub.c:3346 [inline] __put_partials+0x146/0x170 mm/slub.c:3886 put_cpu_partial+0x1f2/0x2d0 mm/slub.c:3961 __slab_free+0x288/0x2a0 mm/slub.c:5956 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:406 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5661 [inline] __kmalloc_noprof+0x41d/0x800 mm/slub.c:5673 kmalloc_noprof include/linux/slab.h:961 [inline] kzalloc_noprof include/linux/slab.h:1094 [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_path_perm+0x213/0x4b0 security/tomoyo/file.c:822 security_inode_getattr+0x12f/0x330 security/security.c:1869 vfs_getattr fs/stat.c:259 [inline] vfs_fstat fs/stat.c:281 [inline] vfs_fstatat+0xb1/0x170 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:542 [inline] __se_sys_newfstatat fs/stat.c:536 [inline] __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f08f458de3a RSP: 002b:00007ffdd5b22618 EFLAGS: 00000206 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f08f458de3a RDX: 00007ffdd5b22620 RSI: 00007f08f4650f82 RDI: 0000000000000003 RBP: 00007ffdd5b22620 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000206 R12: 00000000000000fb R13: 0000000000000000 R14: 00000000000bf70b R15: 00007ffdd5b22770 rcu: rcu_preempt kthread starved for 226 jiffies! g103753 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:27232 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5258 [inline] __schedule+0x150e/0x5070 kernel/sched/core.c:6866 __schedule_loop kernel/sched/core.c:6948 [inline] schedule+0x165/0x360 kernel/sched/core.c:6963 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+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 3409 Comm: kworker/R-bat_e Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Workqueue: bat_events batadv_tt_purge RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:747 Code: c7 c7 20 42 34 8e e8 6f 34 2a 03 eb cc 66 66 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 41 57 41 56 53 65 ff 05 90 68 1c 11 e8 7b 86 bf 09 89 RSP: 0018:ffffc90000007858 EFLAGS: 00000202 RAX: ffffffff8a202632 RBX: 0000000000000001 RCX: 0000000000000100 RDX: ffff888030e50000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000007990 R08: ffffffff8a2025fe R09: ffffffff8e33f2e0 R10: dffffc0000000000 R11: ffffffff8a13f1b0 R12: dffffc0000000000 R13: ffff88803fd506a8 R14: 0000000000000000 R15: ffff88807c9c8000 FS: 0000000000000000(0000) GS:ffff8881259dc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055bc36fc14b0 CR3: 0000000033a0c000 CR4: 00000000003526f0 Call Trace: rcu_read_lock include/linux/rcupdate.h:868 [inline] ipv6_chk_mcast_addr+0x6b/0x860 net/ipv6/mcast.c:1045 ip6_mc_input+0x517/0xb70 net/ipv6/ip6_input.c:530 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318 __netif_receive_skb_one_core net/core/dev.c:6138 [inline] __netif_receive_skb+0xd3/0x380 net/core/dev.c:6251 process_backlog+0x622/0x1500 net/core/dev.c:6603 __napi_poll+0xae/0x320 net/core/dev.c:7667 napi_poll net/core/dev.c:7730 [inline] net_rx_action+0x672/0xe50 net/core/dev.c:7882 handle_softirqs+0x27d/0x850 kernel/softirq.c:626 do_softirq+0xec/0x180 kernel/softirq.c:523 __local_bh_enable_ip+0x17d/0x1c0 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2250 [inline] batadv_tt_purge+0x4d1/0x9e0 net/batman-adv/translation-table.c:3510 process_one_work+0x93a/0x15a0 kernel/workqueue.c:3279 process_scheduled_works kernel/workqueue.c:3362 [inline] rescuer_thread+0x8b7/0x1210 kernel/workqueue.c:3586 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246