rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10431/1:b..l P5621/1:b..l rcu: (detected by 1, t=10503 jiffies, g=35481, q=1764 ncpus=2) task:syz-executor state:R running task stack:21184 pid:5621 tgid:5621 ppid:5616 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_acquire+0x232/0x350 kernel/locking/lockdep.c:5913 Code: ff ff ff e8 20 29 41 0a f7 44 24 10 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 72 54 f1 11 48 3b 44 24 50 75 33 fb 48 83 c4 58 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 cf 2c 44 0a cc 48 8d 3d f7 34 da RSP: 0018:ffffc90003ee74c0 EFLAGS: 00000296 RAX: 8df5fc580b6f1900 RBX: 0000000000000000 RCX: 0000000000000046 RDX: 000000005acdab19 RSI: ffffffff8e6fd63b RDI: ffffffff8c6d9480 RBP: ffff88807e8f9f40 R08: 4400000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: ffffffff8ed5c6e0 R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:309 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] class_rcu_constructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0xac/0x2550 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5815 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4683 [inline] slab_alloc_node mm/slub.c:4996 [inline] kmem_cache_alloc_noprof+0x2b9/0x600 mm/slub.c:5010 alloc_empty_file+0x5b/0x1d0 fs/file_table.c:262 path_openat+0xa2/0x1d60 fs/namei.c:4986 do_file_open+0x23e/0x4a0 fs/namei.c:5029 do_sys_openat2+0x115/0x200 fs/open.c:1417 do_sys_open fs/open.c:1423 [inline] __do_sys_openat fs/open.c:1439 [inline] __se_sys_openat fs/open.c:1434 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1434 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0fd1d9d47c RSP: 002b:00007fff08981ec0 EFLAGS: 00000206 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000000002d5 RCX: 00007f0fd1d9d47c RDX: 0000000000090800 RSI: 00007f0fd1e34966 RDI: 00000000ffffff9c RBP: 00007fff08981f6c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000f0 R13: 0000000000000000 R14: 000000000002d6a4 R15: 00007fff08981fc0 task:syz.4.1253 state:R running task stack:25608 pid:10431 tgid:10431 ppid:5621 task_flags:0x40044c flags:0x00080002 Call Trace: rcu: rcu_preempt kthread starved for 1246 jiffies! g35481 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:28104 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17db/0x58f0 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330 kthread+0x38b/0x480 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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: 5618 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 RIP: 0010:trace_hardirqs_off+0x0/0x40 kernel/trace/trace_preemptirq.c:103 Code: e9 de fe ff ff 90 0f 0b 90 e9 3f ff ff ff 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 53 48 8b 5c 24 08 48 89 df e8 7e 43 14 0a 65 8b 05 cf RSP: 0018:ffffc90000007740 EFLAGS: 00000006 RAX: 0000000000000202 RBX: 0000000000000200 RCX: dffffc0000000000 RDX: 8000000000000300 RSI: 0000000000000200 RDI: ffffffff8aa51641 RBP: ffffc90000007950 R08: 0000000000000100 R09: 0000000000000000 R10: ffffc900000078b0 R11: fffff52000000f1a R12: ffff888078f3a040 R13: dffffc0000000000 R14: ffffffff8aa51641 R15: ffffffff907bb8c0 FS: 000055558ec71500(0000) GS:ffff888124cd9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3278f09ff8 CR3: 0000000074826000 CR4: 00000000003526f0 Call Trace: __local_bh_enable_ip+0x72/0x140 kernel/softirq.c:455 local_bh_enable include/linux/bottom_half.h:33 [inline] ip6t_do_table+0x13c4/0x15b0 net/ipv6/netfilter/ip6_tables.c:375 ip6table_mangle_hook+0x2b8/0x730 net/ipv6/netfilter/ip6table_mangle.c:73 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_slow+0xc5/0x220 net/netfilter/core.c:619 nf_hook include/linux/netfilter.h:280 [inline] NF_HOOK+0x21f/0x3c0 include/linux/netfilter.h:323 __netif_receive_skb_one_core net/core/dev.c:6264 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0x795/0x18b0 net/core/dev.c:6728 __napi_poll+0xaa/0x330 net/core/dev.c:7787 napi_poll net/core/dev.c:7850 [inline] net_rx_action+0x61d/0xf50 net/core/dev.c:8007 handle_softirqs+0x226/0x860 kernel/softirq.c:645 __do_softirq kernel/softirq.c:679 [inline] invoke_softirq kernel/softirq.c:519 [inline] __irq_exit_rcu+0xcb/0x220 kernel/softirq.c:767 irq_exit_rcu+0x9/0x30 kernel/softirq.c:784 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x2e1/0x3c0 kernel/locking/lockdep.c:5934 Code: 66 f1 11 00 00 00 00 eb b5 e8 1b f6 40 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 73 21 f1 11 48 3b 44 24 28 75 48 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 d0 f9 43 0a cc 48 8d 3d 68 05 da RSP: 0018:ffffc90003ec73e8 EFLAGS: 00000286 RAX: e713228ab3f55c00 RBX: 0000000000000206 RCX: 0000000000000046 RDX: ffffc90003ec7501 RSI: ffffffff8e6fd63b RDI: ffffffff8c6d9480 RBP: ffff888036700c50 R08: ffffc90003ec79f8 R09: 0000000000000000 R10: ffffc90003ec7518 R11: fffff520007d8ea5 R12: 0000000000000004 R13: 0000000000000004 R14: ffffffff8ed5c6e0 R15: ffff888036700000 rcu_lock_release include/linux/rcupdate.h:319 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] class_rcu_destructor include/linux/rcupdate.h:1216 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:183 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:338 reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1418 [inline] __free_frozen_pages+0xc93/0xd90 mm/page_alloc.c:2962 __slab_free+0x274/0x2c0 mm/slub.c:5815 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x99/0x100 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:5414 [inline] __kmalloc_noprof+0x36b/0x720 mm/slub.c:5439 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] tomoyo_encode2 security/tomoyo/realpath.c:45 [inline] tomoyo_encode+0x2ad/0x570 security/tomoyo/realpath.c:80 tomoyo_realpath_from_path+0x5fa/0x640 security/tomoyo/realpath.c:283 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 tomoyo_path_rmdir+0xaa/0xf0 security/tomoyo/tomoyo.c:195 security_path_rmdir+0x15f/0x330 security/security.c:1467 filename_rmdir+0x20d/0x520 fs/namei.c:5569 __do_sys_unlinkat fs/namei.c:5747 [inline] __se_sys_unlinkat+0x71/0x1a0 fs/namei.c:5740 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f306559d277 Code: 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 b8 07 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd71d20a58 EFLAGS: 00000207 ORIG_RAX: 0000000000000107 RAX: ffffffffffffffda RBX: 0000000000000065 RCX: 00007f306559d277 RDX: 0000000000000200 RSI: 00007ffd71d21ba0 RDI: 00000000ffffff9c RBP: 00007f3065634474 R08: 00000000000065d0 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000207 R12: 00007ffd71d21ba0 R13: 00007f3065634474 R14: 000000000002d977 R15: 00007ffd71d21be0