bridge0: port 1(bridge_slave_0) entered forwarding state bridge0: topology change detected, propagating bridge0: port 2(bridge_slave_1) entered forwarding state bridge0: topology change detected, propagating rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4634/1:b..l rcu: (detected by 1, t=10502 jiffies, g=238717, q=425 ncpus=2) task:syz.2.7807 state:R running task stack:26312 pid:4634 tgid:4630 ppid:30094 task_flags:0x40054c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7556 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8f0 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline] RIP: 0010:unwind_next_frame+0xcb7/0x2550 arch/x86/kernel/unwind_orc.c:614 Code: 4c 39 f8 0f 96 c0 20 c8 3c 01 0f 85 76 0e 00 00 48 89 d7 e8 eb 23 00 00 48 89 c3 49 bc 00 00 00 00 00 fc ff df 48 8b 44 24 20 <42> 80 3c 20 00 4d 8d 7e 48 74 08 4c 89 ff e8 b6 06 bd 00 49 89 1f RSP: 0018:ffffc9000685f2a0 EFLAGS: 00000202 RAX: 1ffff92000d0be72 RBX: ffffffff82346363 RCX: 1ffff92000d0be01 RDX: ffffc9000685f6c0 RSI: 0000000000000002 RDI: ffffc9000685f6c0 RBP: 1ffffffff21f9181 R08: ffffc9000685f6c8 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8eb59c60 R12: dffffc0000000000 R13: ffffc90006860000 R14: ffffc9000685f348 R15: ffffc90006858000 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 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __kmalloc_cache_noprof+0x32d/0x660 mm/slub.c:5515 _kmalloc_noprof include/linux/slab.h:969 [inline] slab_free_hook mm/slub.c:2657 [inline] slab_free mm/slub.c:6405 [inline] kmem_cache_free+0x156/0x650 mm/slub.c:6532 tear_down_vmas+0x312/0x520 mm/mmap.c:1262 exit_mmap+0x4ca/0x9f0 mm/mmap.c:1320 __mmput+0x118/0x420 kernel/fork.c:1187 exit_mm+0x221/0x2d0 kernel/exit.c:615 do_exit+0x6cd/0x2360 kernel/exit.c:997 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 get_signal+0x121b/0x12c0 kernel/signal.c:3046 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+0x104/0x730 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:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f4fec39de99 RSP: 002b:00007f4fed2e70e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f4fec625fa8 RCX: 00007f4fec39de99 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f4fec625fa8 RBP: 00007f4fec625fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4fec626038 R14: 00007fff8be51340 R15: 00007fff8be51428 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g238717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=90248 rcu: rcu_preempt kthread starved for 10502 jiffies! g238717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26848 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 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: 4638 Comm: syz.4.7810 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:instrument_read_write include/linux/instrumented.h:55 [inline] RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline] RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] RIP: 0010:do_raw_spin_lock+0x121/0x2f0 kernel/locking/spinlock_debug.c:116 Code: c8 0f 84 2b 01 00 00 41 c6 44 14 04 04 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 49 89 d6 e8 a4 40 91 00 48 8d 7c 24 40 04 00 00 00 e8 95 40 91 00 8b 44 24 40 b9 01 00 00 00 f0 0f b1 RSP: 0018:ffffc90000007c80 EFLAGS: 00000056 RAX: 00000000ffffff01 RBX: ffffffff9aa33a10 RCX: ffffffff81a3567c RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007cc0 RBP: ffffc90000007d40 R08: ffffffff9aa33a13 R09: 1ffffffff3546742 R10: dffffc0000000000 R11: fffffbfff3546743 R12: 1ffff92000000f94 R13: ffffffff9aa33a18 R14: dffffc0000000000 R15: 1ffffffff3546743 FS: 00007f252e8ed6c0(0000) GS:ffff888124f53000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000012c0 CR3: 000000004747e000 CR4: 00000000003526f0 Call Trace: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock_irqsave+0x4c/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:936 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x239/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 ad 8c cf f5 f7 c3 00 02 00 00 74 05 e8 a0 6e fb f5 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 b4 a2 c0 f5 65 8b 05 ad 02 99 07 85 c0 74 18 5b 41 5e e9 91 48 RSP: 0018:ffffc900038e6ee8 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000282 RCX: 0000000080000202 RDX: 0000000000000002 RSI: ffffffff8e22e909 RDI: 0000000000000001 RBP: ffffc900038e71d0 R08: ffffffff90579037 R09: 1ffffffff20af206 R10: dffffc0000000000 R11: fffffbfff20af207 R12: ffff8880121db2a8 R13: dffffc0000000000 R14: ffff8880121db2a8 R15: ffff8880121db2f8 spin_unlock_irqrestore include/linux/spinlock.h:408 [inline] taprio_change+0x34f3/0x4640 net/sched/sch_taprio.c:1989 taprio_init+0x994/0xc00 net/sched/sch_taprio.c:2128 qdisc_create+0x7b5/0xf00 net/sched/sch_api.c:1337 __tc_modify_qdisc net/sched/sch_api.c:1771 [inline] tc_modify_qdisc+0x17af/0x2390 net/sched/sch_api.c:1835 rtnetlink_rcv_msg+0x7b9/0xc00 net/core/rtnetlink.c:7121 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775 __sock_sendmsg net/socket.c:790 [inline] ____sys_sendmsg+0x54e/0x850 net/socket.c:2684 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738 __sys_sendmsg net/socket.c:2770 [inline] __do_sys_sendmsg net/socket.c:2775 [inline] __se_sys_sendmsg net/socket.c:2773 [inline] __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f252d99de99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007f252e8ed028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f252dc25fa0 RCX: 00007f252d99de99 RDX: 0000000004004080 RSI: 00002000000012c0 RDI: 0000000000000008 RBP: 00007f252da33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f252dc26038 R14: 00007f252dc25fa0 R15: 00007ffffa4f6198 GRED: Unable to relocate VQ 0x0 after dequeue, screwing up backlog