rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13789/1:b..l P10756/1:b..l P11603/1:b..l rcu: (detected by 1, t=10502 jiffies, g=59061, q=773 ncpus=2) task:kworker/u8:30 state:R running task stack:25480 pid:11603 tgid:11603 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:688 RIP: 0010:rcu_is_watching+0x5/0xc0 kernel/rcu/tree.c:747 Code: 6c 3e 03 e9 51 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <53> 65 ff 05 a3 9e 0f 12 e8 ae 0d d5 09 48 c7 c3 e8 e9 b3 93 89 c5 RSP: 0018:ffffc9000cd37518 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 00000000e081e03e RDX: ffffffff816cb66d RSI: ffffffff8daa7dd4 RDI: ffffffff8bf2b380 RBP: ffffc9000cd375e0 R08: 000000003927ff1e R09: 00000000e3927ff1 R10: 0000000000000002 R11: ffff88802627aff0 R12: ffffffff81a960d0 R13: ffffc9000cd37598 R14: 0000000000000000 R15: ffff88802627a4c0 rcu_read_lock include/linux/rcupdate.h:868 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xa86/0x20b0 arch/x86/kernel/unwind_orc.c:495 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_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_node_track_caller_noprof+0x353/0x930 mm/slub.c:5764 kmalloc_reserve+0xef/0x2c0 net/core/skbuff.c:608 pskb_expand_head+0x238/0xf80 net/core/skbuff.c:2282 __skb_cow include/linux/skbuff.h:3853 [inline] skb_cow_head include/linux/skbuff.h:3887 [inline] batadv_skb_head_push+0xf5/0x290 net/batman-adv/mesh-interface.c:71 batadv_send_skb_packet+0xef/0x6f0 net/batman-adv/send.c:81 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:391 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x734/0x920 net/batman-adv/bat_iv_ogm.c:1697 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 task:syz-executor state:R running task stack:24104 pid:10756 tgid:10756 ppid:10747 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872 Code: b4 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 72 b8 ee 0e 0f 82 74 02 00 00 8b 35 0a e9 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 89 b4 18 12 0f 85 ad 02 00 00 48 83 c4 RSP: 0018:ffffc9001b6b76e0 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3c9620 RCX: 0000000072d19b33 RDX: 0000000000000000 RSI: ffffffff8daa7dd4 RDI: ffffffff8bf2b380 RBP: 0000000000000002 R08: 00000000fd501b8c R09: 00000000cfd501b8 R10: 0000000000000002 R11: ffff88807ae80b30 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+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 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_save_track+0x14/0x30 mm/kasan/common.c:77 poison_kmalloc_redzone mm/kasan/common.c:397 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:414 kasan_kmalloc include/linux/kasan.h:262 [inline] __do_kmalloc_node mm/slub.c:5657 [inline] __kmalloc_noprof+0x33d/0x910 mm/slub.c:5669 kmalloc_noprof include/linux/slab.h:961 [inline] tomoyo_realpath_from_path+0xc2/0x6e0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_number_perm+0x245/0x580 security/tomoyo/file.c:723 security_file_ioctl+0x9b/0x240 security/security.c:2435 __do_sys_ioctl fs/ioctl.c:591 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0xb7/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4afdd8f34b RSP: 002b:00007ffdadec3990 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f4afdd8f34b RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003 RBP: 00007ffdadec3a2c R08: 0000000000000000 R09: 00007ffdadec3737 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000008b R13: 000000000000005f R14: 00000000000b69b5 R15: 00007ffdadec3a80 task:syz.7.2001 state:R running task stack:25992 pid:13789 tgid:13787 ppid:10758 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872 Code: b4 18 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 72 b8 ee 0e 0f 82 74 02 00 00 8b 35 0a e9 ee 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 89 b4 18 12 0f 85 ad 02 00 00 48 83 c4 RSP: 0018:ffffc90005396c40 EFLAGS: 00000206 RAX: 0000000000000046 RBX: ffffffff8e3c9620 RCX: 0000000013d622c6 RDX: 0000000000000000 RSI: ffffffff8daa7dd4 RDI: ffffffff8bf2b380 RBP: 0000000000000002 R08: 00000000accd7842 R09: 000000002accd784 R10: 0000000000000002 R11: ffff8880300b0b30 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+0xd1/0x20b0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x160/0x1f0 mm/page_owner.c:165 __set_page_owner+0x91/0x560 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x1af/0x220 mm/page_alloc.c:1846 prep_new_page mm/page_alloc.c:1854 [inline] get_page_from_freelist+0xd0b/0x31a0 mm/page_alloc.c:3915 __alloc_frozen_pages_noprof+0x25f/0x2430 mm/page_alloc.c:5210 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x36/0x2f0 mm/mempolicy.c:2505 shmem_alloc_folio+0x135/0x160 mm/shmem.c:1890 shmem_alloc_and_add_folio+0x494/0xc20 mm/shmem.c:1932 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2556 shmem_fault+0x1fe/0xa00 mm/shmem.c:2757 __do_fault+0x10d/0x490 mm/memory.c:5320 do_shared_fault mm/memory.c:5819 [inline] do_fault+0x302/0x1ad0 mm/memory.c:5893 do_pte_missing mm/memory.c:4401 [inline] handle_pte_fault mm/memory.c:6273 [inline] __handle_mm_fault+0x1919/0x2bb0 mm/memory.c:6411 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x54e/0x3590 mm/gup.c:1428 __get_user_pages_locked mm/gup.c:1692 [inline] faultin_page_range+0x338/0x940 mm/gup.c:1912 madvise_populate mm/madvise.c:976 [inline] madvise_do_behavior+0x34c/0x530 mm/madvise.c:1935 do_madvise+0x176/0x240 mm/madvise.c:2030 __do_sys_madvise mm/madvise.c:2039 [inline] __se_sys_madvise mm/madvise.c:2037 [inline] __x64_sys_madvise+0xa9/0x110 mm/madvise.c:2037 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdc34d8f749 RSP: 002b:00007fdc35b94038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007fdc34fe5fa0 RCX: 00007fdc34d8f749 RDX: 0000000000000017 RSI: 0000000000c00304 RDI: 0000200000000000 RBP: 00007fdc34e13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdc34fe6038 R14: 00007fdc34fe5fa0 R15: 00007ffc0e13afe8 rcu: rcu_preempt kthread starved for 10600 jiffies! g59061 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:28208 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 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+0x983/0xb10 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: CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 49 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 0000000002ba4ca3 RBX: 0000000000000001 RCX: ffffffff8b7816d9 RDX: 0000000000000000 RSI: ffffffff8dacde6c RDI: ffffffff8bf2b380 RBP: ffffed1003b56498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dab2ff0 R12: 0000000000000001 R13: ffff88801dab24c0 R14: ffffffff9088b3d0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fbe989caff8 CR3: 000000005e391000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148