rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11180/1:b..l rcu: (detected by 0, t=10516 jiffies, g=53677, q=1233 ncpus=2) task:syz.3.1218 state:R running task stack:26624 pid:11180 tgid:11172 ppid:5615 task_flags:0x40044c flags:0x00080002 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:check_kcov_mode kernel/kcov.c:179 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x18/0x80 kernel/kcov.c:213 Code: cc cc 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 0d d8 b4 cc 11 65 48 8b 15 d8 b4 cc 11 c2 00 01 00 ff 74 29 89 d6 81 e6 00 01 00 0f 81 fe 00 01 00 00 RSP: 0018:ffffc9000ffc7710 EFLAGS: 00000246 RAX: ffffffff8243550a RBX: ffffffff82435262 RCX: ffff88807f68be80 RDX: 8000000000000000 RSI: ffffffff8c6d9460 RDI: ffffffff8c6d9420 RBP: 0000000000000001 R08: 3b00000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ed5c6e0 R12: ffffea0001447440 R13: dffffc0000000000 R14: 00000000000511d1 R15: 0000000000000000 __static_cpu_has arch/x86/include/asm/cpufeature.h:101 [inline] __nr_to_section include/linux/mmzone.h:2063 [inline] __pfn_to_section include/linux/mmzone.h:2193 [inline] lookup_page_ext mm/page_ext.c:250 [inline] page_ext_get+0x2ca/0x2e0 mm/page_ext.c:523 __reset_page_owner+0x28/0x1f0 mm/page_owner.c:324 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 tlb_batch_list_free mm/mmu_gather.c:161 [inline] tlb_finish_mmu+0x13e/0x220 mm/mmu_gather.c:552 exit_mmap+0x4b2/0x9f0 mm/mmap.c:1328 __mmput+0x118/0x420 kernel/fork.c:1193 exit_mm+0x221/0x2d0 kernel/exit.c:614 do_exit+0x6cd/0x2360 kernel/exit.c:996 do_group_exit+0x22d/0x2f0 kernel/exit.c:1151 get_signal+0x121b/0x12c0 kernel/signal.c:3039 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x10e/0x770 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:336 [inline] do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff66bf5e98e RSP: 002b:00007ff66a1f4f38 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007ff66a1f66c0 RCX: 00007ff66bf5e98e RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff66c226218 R14: 00007ff66c226180 R15: 00007ffc430382d8 rcu: rcu_preempt kthread starved for 316 jiffies! g53677 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 60 Comm: kworker/u8:5 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:65 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:141 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x67/0x2c0 mm/kasan/generic.c:200 Code: 00 ff 4c 39 cf 0f 82 14 02 00 00 49 89 ff 49 c1 ef 03 49 ba 00 00 00 00 00 fc ff df 4f 8d 1c 17 49 ff c8 4d 89 c1 49 c1 e9 03 <48> bb 01 00 00 00 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 RSP: 0018:ffffc90000a17ae8 EFLAGS: 00000a07 RAX: ffffc9000201ff01 RBX: 0000000000000010 RCX: ffffffff8177fea4 RDX: 0000000000000001 RSI: 0000000000000010 RDI: ffffc90000a17c38 RBP: 0000000000000000 R08: ffffc90000a17c47 R09: 1ffff92000142f88 R10: dffffc0000000000 R11: fffff52000142f87 R12: dffffc0000000000 R13: ffffffff9110b41e R14: ffffc90000a17c38 R15: 1ffff92000142f87 FS: 0000000000000000(0000) GS:ffff888124dd9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f10ae3ed158 CR3: 000000007f7ea000 CR4: 00000000003526f0 Call Trace: __asan_memset+0x22/0x50 mm/kasan/shadow.c:84 unwind_next_frame+0xd04/0x2550 arch/x86/kernel/unwind_orc.c:621 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2748 [inline] slab_free mm/slub.c:6499 [inline] kmem_cache_free+0x182/0x650 mm/slub.c:6626 kfree_skb_reason include/linux/skbuff.h:1323 [inline] kfree_skb include/linux/skbuff.h:1332 [inline] ip6_mc_input+0x878/0xc80 net/ipv6/ip6_input.c:639 ip_sabotage_in+0x1e1/0x270 net/bridge/br_netfilter_hooks.c:988 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] netif_receive_skb_internal net/core/dev.c:6463 [inline] netif_receive_skb+0x278/0xbf0 net/core/dev.c:6522 NF_HOOK+0xa4/0x3a0 include/linux/netfilter.h:325 br_handle_frame_finish+0x1136/0x1950 net/bridge/br_input.c:-1 br_nf_hook_thresh+0x3dd/0x4c0 net/bridge/br_netfilter_hooks.c:-1 br_nf_pre_routing_finish_ipv6+0x90c/0xc40 net/bridge/br_netfilter_ipv6.c:-1 NF_HOOK include/linux/netfilter.h:325 [inline] br_nf_pre_routing_ipv6+0x382/0x6f0 net/bridge/br_netfilter_ipv6.c:183 nf_hook_entry_hookfn include/linux/netfilter.h:165 [inline] nf_hook_bridge_pre net/bridge/br_input.c:291 [inline] br_handle_frame+0x127f/0x1510 net/bridge/br_input.c:442 __netif_receive_skb_core+0x989/0x30c0 net/core/dev.c:6151 __netif_receive_skb_one_core net/core/dev.c:6262 [inline] __netif_receive_skb net/core/dev.c:6377 [inline] process_backlog+0x727/0x18b0 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+0x77/0xd0 kernel/softirq.c:546 __local_bh_enable_ip+0x100/0x140 kernel/softirq.c:473 spin_unlock_bh include/linux/spinlock.h:407 [inline] batadv_tt_local_purge+0x2c1/0x340 net/batman-adv/translation-table.c:1402 batadv_tt_purge+0x35/0xa10 net/batman-adv/translation-table.c:3753 process_one_work kernel/workqueue.c:3396 [inline] process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560 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 net_ratelimit: 14641 callbacks suppressed