rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P31068/1:b..l P31067/1:b..l P30827/1:b..l P5828/1:b..l P31061/1:b..l rcu: (detected by 0, t=10502 jiffies, g=158597, q=1094 ncpus=1) task:syz.0.11434 state:R running task stack:27912 pid:31061 tgid:31061 ppid:5824 task_flags:0x40004c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7095 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] zap_pte_range mm/memory.c:1959 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x152f/0x4840 mm/memory.c:2091 unmap_single_vma+0x153/0x240 mm/memory.c:2133 unmap_vmas+0x295/0x590 mm/memory.c:2171 exit_mmap+0x1ef/0xa30 mm/mmap.c:1302 __mmput+0x12a/0x410 kernel/fork.c:1175 mmput+0x67/0x80 kernel/fork.c:1198 exit_mm kernel/exit.c:581 [inline] do_exit+0x819/0x2b60 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118 __do_sys_exit_group kernel/exit.c:1129 [inline] __se_sys_exit_group kernel/exit.c:1127 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1127 x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9ca059c819 RSP: 002b:00007ffc773d1368 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f9ca059c819 RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007ffc773d13cc R08: 0000000000000000 R09: 00000000000927c0 R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000b21 R13: 00000000000927c0 R14: 00000000000bb6c7 R15: 00007ffc773d1420 task:kworker/0:3 state:R running task stack:24824 pid:5828 tgid:5828 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217 Code: 05 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 87 89 09 8b 82 a4 16 00 00 85 c0 74 f1 8b 82 80 16 00 00 <83> f8 02 75 e6 48 8b 8a 88 16 00 00 8b 92 84 16 00 00 48 8b 01 48 RSP: 0018:ffffc90003b77b40 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff89ac814e RDX: ffff88807de2db80 RSI: ffffffff89ac815c RDI: ffff88807de2db80 RBP: ffff88814ac00000 R08: 0000000000000004 R09: 0000000000003240 R10: 0000000000040000 R11: 0000000000000000 R12: dffffc0000000000 R13: 0000000000040000 R14: 0000000000003240 R15: 0000000000001770 gc_worker+0x32c/0x1630 net/netfilter/nf_conntrack_core.c:1554 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3288 process_scheduled_works kernel/workqueue.c:3371 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3452 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:udevd state:R running task stack:27912 pid:30827 tgid:30827 ppid:5194 task_flags:0x40014c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__sanitizer_cov_trace_pc+0x3f/0x70 kernel/kcov.c:217 Code: 05 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 00 ff 00 74 05 e9 11 87 89 09 8b 82 a4 16 00 00 85 c0 74 f1 8b 82 80 16 00 00 <83> f8 02 75 e6 48 8b 8a 88 16 00 00 8b 92 84 16 00 00 48 8b 01 48 RSP: 0018:ffffc90004f37668 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8218f022 RDX: ffff888020379e80 RSI: ffffffff82182b4b RDI: ffffffff8e411470 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 00007f6f1fcf16c5 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff888020379e80 raw_read_seqcount_latch_retry include/linux/seqlock.h:675 [inline] read_seqcount_latch_retry include/linux/seqlock.h:690 [inline] latch_tree_find include/linux/rbtree_latch.h:211 [inline] bpf_ksym_find+0xeb/0x1c0 kernel/bpf/core.c:716 is_bpf_text_address+0x58/0x1a0 kernel/bpf/core.c:749 kernel_text_address kernel/extable.c:125 [inline] kernel_text_address+0x8d/0x100 kernel/extable.c:94 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x59/0xa0 arch/x86/kernel/unwind_orc.c:385 arch_stack_walk+0xa6/0xf0 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kmalloc_noprof include/linux/slab.h:950 [inline] slab_free_hook mm/slub.c:2637 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x41f/0x6a0 mm/slub.c:6295 tear_down_vmas+0x2a5/0x600 mm/mmap.c:1264 exit_mmap+0x469/0xa30 mm/mmap.c:1322 __mmput+0x12a/0x410 kernel/fork.c:1175 mmput+0x67/0x80 kernel/fork.c:1198 exit_mm kernel/exit.c:581 [inline] do_exit+0x819/0x2b60 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118 __do_sys_exit_group kernel/exit.c:1129 [inline] __se_sys_exit_group kernel/exit.c:1127 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1127 x64_sys_call+0x102c/0x1530 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f1fcf16c5 RSP: 002b:00007ffde0cab068 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00005597a9616090 RCX: 00007f6f1fcf16c5 RDX: 00000000000000e7 RSI: fffffffffffffe68 RDI: 0000000000000000 RBP: 00005597a95f5910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffde0cab0b0 R14: 0000000000000000 R15: 0000000000000000 task:syz.1.11436 state:R running task stack:27496 pid:31067 tgid:31065 ppid:5823 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x2d/0x380 kernel/locking/lockdep.c:5828 Code: fa 41 57 41 56 41 89 f6 41 55 45 89 c5 41 54 41 89 cc 55 48 89 fd 53 89 d3 48 83 ec 38 65 4c 8b 3d a0 95 29 12 4c 89 7c 24 30 <4d> 89 cf 66 90 65 8b 05 bb 95 29 12 83 f8 07 0f 87 f0 00 00 00 48 RSP: 0018:ffffc900033ef820 EFLAGS: 00000282 RAX: ffffffff81b7bd3d RBX: 0000000000000000 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e7e75e0 RBP: ffffffff8e7e75e0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000200 R11: 00000000000164ee R12: 0000000000000002 R13: 0000000000000000 R14: 0000000000000000 R15: 9f14bd6b57466f00 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 save_stack+0x162/0x1e0 mm/page_owner.c:165 __reset_page_owner+0x84/0x190 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] __free_frozen_pages+0x7e1/0x10d0 mm/page_alloc.c:2978 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xe0 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x1a0/0x1f0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:350 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4538 [inline] slab_alloc_node mm/slub.c:4866 [inline] __kmalloc_cache_noprof+0x243/0x6f0 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] io_ring_ctx_alloc io_uring/io_uring.c:229 [inline] io_uring_create io_uring/io_uring.c:2946 [inline] io_uring_setup.cold+0x6c/0x1d79 io_uring/io_uring.c:3079 __do_sys_io_uring_setup io_uring/io_uring.c:3113 [inline] __se_sys_io_uring_setup io_uring/io_uring.c:3104 [inline] __x64_sys_io_uring_setup+0xc2/0x170 io_uring/io_uring.c:3104 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f138b79c819 RSP: 002b:00007f138c57c028 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 00007f138ba15fa0 RCX: 00007f138b79c819 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 00007f138b832c91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f138ba16038 R14: 00007f138ba15fa0 R15: 00007ffcd686f1b8 task:syz.3.11437 state:R running task stack:27320 pid:31068 tgid:31066 ppid:5825 task_flags:0x40054c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7095 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] zap_pte_range mm/memory.c:1959 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x152f/0x4840 mm/memory.c:2091 unmap_single_vma+0x153/0x240 mm/memory.c:2133 unmap_vmas+0x295/0x590 mm/memory.c:2171 exit_mmap+0x1ef/0xa30 mm/mmap.c:1302 __mmput+0x12a/0x410 kernel/fork.c:1175 mmput+0x67/0x80 kernel/fork.c:1198 exit_mm kernel/exit.c:581 [inline] do_exit+0x819/0x2b60 kernel/exit.c:964 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x4a0 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x668/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2d1e39c819 RSP: 002b:00007f2d1f1e00e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f2d1e615fa8 RCX: 00007f2d1e39c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f2d1e615fa8 RBP: 00007f2d1e615fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2d1e616038 R14: 00007ffef456c420 R15: 00007ffef456c508 rcu: rcu_preempt kthread starved for 712 jiffies! g158597 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0xfee/0x6120 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7008 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 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: CPU: 0 UID: 0 PID: 3408 Comm: kworker/R-bat_e Tainted: G U I L syzkaller #0 PREEMPT(full) Tainted: [U]=USER, [I]=FIRMWARE_WORKAROUND, [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:preempt_count_sub+0xc/0x160 kernel/sched/core.c:5788 Code: 1e fa 48 c7 c7 20 ad 14 94 e9 30 00 6b 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 c7 c0 c0 83 1d 9b 53 <89> fb 48 ba 00 00 00 00 00 fc ff df 48 89 c1 83 e0 07 48 c1 e9 03 RSP: 0018:ffffc90000007498 EFLAGS: 00000246 RAX: ffffffff9b1d83c0 RBX: ffffffff906c0ee0 RCX: 0000000000000004 RDX: 0000000000000000 RSI: ffffffff8de83a76 RDI: 0000000000000001 RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000246 R13: 0000000000000000 R14: ffff88802d42b000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff888124340000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555d7477d0 CR3: 0000000038f6c000 CR4: 00000000003526f0 Call Trace: __raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:264 [inline] _raw_read_unlock_irqrestore+0x3b/0x80 kernel/locking/spinlock.c:268 netlink_lock_table net/netlink/af_netlink.c:454 [inline] netlink_broadcast_filtered+0x112/0xf50 net/netlink/af_netlink.c:1530 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline] nlmsg_multicast include/net/netlink.h:1184 [inline] nlmsg_notify+0xb1/0x290 net/netlink/af_netlink.c:2593 fdb_notify+0xfb/0x190 net/bridge/br_fdb.c:199 br_fdb_update+0x324/0x720 net/bridge/br_fdb.c:1046 br_handle_frame_finish+0xe9a/0x1f60 net/bridge/br_input.c:144 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline] br_handle_frame+0x977/0x1520 net/bridge/br_input.c:442 __netif_receive_skb_core.constprop.0+0x6c5/0x3550 net/core/dev.c:6068 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:6179 __netif_receive_skb+0x1f/0x120 net/core/dev.c:6294 process_backlog+0x37a/0x1580 net/core/dev.c:6645 __napi_poll.constprop.0+0xaf/0x450 net/core/dev.c:7709 napi_poll net/core/dev.c:7772 [inline] net_rx_action+0xa40/0xf20 net/core/dev.c:7929 handle_softirqs+0x1eb/0x9e0 kernel/softirq.c:622 do_softirq kernel/softirq.c:523 [inline] do_softirq+0xac/0xe0 kernel/softirq.c:510 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450 spin_unlock_bh include/linux/spinlock.h:395 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2255 [inline] batadv_tt_purge+0x25d/0xbd0 net/batman-adv/translation-table.c:3515 process_one_work+0xa23/0x19a0 kernel/workqueue.c:3288 process_scheduled_works kernel/workqueue.c:3371 [inline] rescuer_thread+0x905/0x14a0 kernel/workqueue.c:3595 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245