rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=39241, q=27 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4294972246-4294961744), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g39241 f0x2 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:27848 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7429 Comm: syz.4.942 Not tainted 6.1.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:check_preemption_disabled+0x1/0x110 lib/smp_processor_id.c:13 Code: 00 91 9c 8c 4c 89 f6 e8 cd d3 1f fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 00 12 bf 8a 48 c7 c6 40 12 bf 8a eb 00 55 <41> 57 41 56 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc900001e0c28 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff88807aa95940 RCX: 0000000000000001 RDX: ffff88807aa95940 RSI: ffffffff8a6c1180 RDI: ffffffff8abf1260 RBP: 0000000000000001 R08: 0000000000000004 R09: 0000000000000003 R10: fffff5200003c180 R11: 1ffff9200003c180 R12: 0000000000000002 R13: 0000000000000046 R14: ffff888052930300 R15: ffff88807aa96470 FS: 00007f4dd32176c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c30d4a8 CR3: 00000000633e0000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000004144 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_is_held_type+0x100/0x190 kernel/locking/lockdep.c:5706 lock_is_held include/linux/lockdep.h:283 [inline] advance_sched+0xd6/0x970 net/sched/sch_taprio.c:703 __run_hrtimer kernel/time/hrtimer.c:1691 [inline] __hrtimer_run_queues+0x522/0xc80 kernel/time/hrtimer.c:1755 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1817 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:console_emit_next_record+0xab0/0xc90 kernel/printk/printk.c:2786 Code: f6 6d 1a 00 4d 85 ff 75 16 e8 ec 6d 1a 00 eb 15 e8 e5 6d 1a 00 e8 c0 c7 a8 08 4d 85 ff 74 ea e8 d6 6d 1a 00 fb 48 8b 5c 24 48 <48> c7 84 24 80 00 00 00 0e 36 e0 45 4a c7 04 2b 00 00 00 00 4a c7 RSP: 0018:ffffc9000546e9a0 EFLAGS: 00000283 RAX: ffffffff8166693a RBX: 1ffff92000a8dd44 RCX: 0000000000080000 RDX: ffffc90012588000 RSI: 0000000000020b74 RDI: 0000000000020b75 RBP: ffffc9000546ebe0 R08: dffffc0000000000 R09: fffffbfff2117049 R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: ffffffff816666bd R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000200 console_flush_all kernel/printk/printk.c:-1 [inline] console_unlock+0x223/0x630 kernel/printk/printk.c:2906 vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303 _printk+0xcc/0x110 kernel/printk/printk.c:2328 br_set_state+0x45e/0x6f0 net/bridge/br_stp.c:57 br_init_port+0x95/0x200 net/bridge/br_stp_if.c:39 new_nbp+0x2f9/0x430 net/bridge/br_if.c:442 br_add_if+0x28b/0xec0 net/bridge/br_if.c:599 do_set_master net/core/rtnetlink.c:2630 [inline] rtnl_newlink_create net/core/rtnetlink.c:3439 [inline] __rtnl_newlink net/core/rtnetlink.c:3642 [inline] rtnl_newlink+0x1bdb/0x1ff0 net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x79b/0xed0 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2493 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x74c/0x8c0 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x89e/0xbc0 net/netlink/af_netlink.c:1859 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x59b/0x970 net/socket.c:2519 ___sys_sendmsg+0x21c/0x290 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x19e/0x270 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4dd238e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4dd3217038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f4dd25b5fa0 RCX: 00007f4dd238e969 RDX: 0000000000004000 RSI: 0000200000000280 RDI: 0000000000000003 RBP: 00007f4dd2410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4dd25b5fa0 R15: 00007ffc29f18c88 watchdog: BUG: soft lockup - CPU#0 stuck for 225s! [kworker/u4:14:7115] Modules linked in: irq event stamp: 128942 hardirqs last enabled at (128941): [] asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 hardirqs last disabled at (128942): [] sysvec_apic_timer_interrupt+0xa/0xc0 arch/x86/kernel/apic/apic.c:1118 softirqs last enabled at (80860): [] __do_softirq kernel/softirq.c:612 [inline] softirqs last enabled at (80860): [] invoke_softirq kernel/softirq.c:452 [inline] softirqs last enabled at (80860): [] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:661 softirqs last disabled at (80811): [] __do_softirq kernel/softirq.c:612 [inline] softirqs last disabled at (80811): [] invoke_softirq kernel/softirq.c:452 [inline] softirqs last disabled at (80811): [] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:661 CPU: 0 PID: 7115 Comm: kworker/u4:14 Not tainted 6.1.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:424 [inline] RIP: 0010:smp_call_function_many_cond+0xe7b/0x1270 kernel/smp.c:998 Code: 00 00 00 41 8b 1f 89 de 83 e6 01 31 ff e8 6d e9 0a 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 f9 e5 0a 00 eb 37 f3 90 <41> 0f b6 04 1c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 de e5 0a RSP: 0018:ffffc900038f7800 EFLAGS: 00000293 RAX: ffffffff8175f132 RBX: dffffc0000000000 RCX: ffff88805c629dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900038f7960 R08: dffffc0000000000 R09: fffffbfff2117049 R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: 1ffff110171e81b9 R13: ffff8880b8e3bb00 R14: 0000000000000001 R15: ffff8880b8f40dc8 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2d4acd CR3: 000000000c68e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1166 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:1574 [inline] text_poke_bp_batch+0x2b0/0x7d0 arch/x86/kernel/alternative.c:1774 text_poke_flush arch/x86/kernel/alternative.c:1965 [inline] text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1972 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x11f/0x240 kernel/jump_label.c:207 static_key_enable+0x16/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xb4/0x430 mm/kfence/core.c:805 process_one_work+0x898/0x1160 kernel/workqueue.c:2292 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7429 Comm: syz.4.942 Not tainted 6.1.140-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:instrument_atomic_read_write include/linux/instrumented.h:102 [inline] RIP: 0010:test_and_set_bit include/asm-generic/bitops/instrumented-atomic.h:71 [inline] RIP: 0010:__netif_schedule+0x83/0x2c0 net/core/dev.c:3142 Code: f2 48 b9 00 00 00 00 00 fc ff df 49 89 44 0d 00 66 41 c7 44 0d 09 f3 f3 41 c6 44 0d 0b f3 e8 74 89 66 f9 48 8d bb 58 01 00 00 08 00 00 00 e8 03 01 b8 f9 31 f6 f0 48 0f ba ab 58 01 00 00 00 RSP: 0018:ffffc900001e0ba0 EFLAGS: 00000006 RAX: ffffffff881a4d9c RBX: ffff888052930000 RCX: ffff88807aa95940 RDX: 0000000000010000 RSI: ffffffff8abf1240 RDI: ffff888052930158 RBP: ffffc900001e0c70 R08: dffffc0000000000 R09: fffffbfff2117049 R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: ffff8880529302e8 R13: 1ffff9200003c178 R14: ffff888052930000 R15: 18543ce62c000000 FS: 00007f4dd32176c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c30d4a8 CR3: 00000000633e0000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000004144 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: advance_sched+0x76e/0x970 net/sched/sch_taprio.c:754 __run_hrtimer kernel/time/hrtimer.c:1691 [inline] __hrtimer_run_queues+0x522/0xc80 kernel/time/hrtimer.c:1755 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1817 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1107 [inline] __sysvec_apic_timer_interrupt+0x153/0x5a0 arch/x86/kernel/apic/apic.c:1124 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1118 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:console_emit_next_record+0xab0/0xc90 kernel/printk/printk.c:2786 Code: f6 6d 1a 00 4d 85 ff 75 16 e8 ec 6d 1a 00 eb 15 e8 e5 6d 1a 00 e8 c0 c7 a8 08 4d 85 ff 74 ea e8 d6 6d 1a 00 fb 48 8b 5c 24 48 <48> c7 84 24 80 00 00 00 0e 36 e0 45 4a c7 04 2b 00 00 00 00 4a c7 RSP: 0018:ffffc9000546e9a0 EFLAGS: 00000283 RAX: ffffffff8166693a RBX: 1ffff92000a8dd44 RCX: 0000000000080000 RDX: ffffc90012588000 RSI: 0000000000020b74 RDI: 0000000000020b75 RBP: ffffc9000546ebe0 R08: dffffc0000000000 R09: fffffbfff2117049 R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: ffffffff816666bd R13: dffffc0000000000 R14: 0000000000000001 R15: 0000000000000200 console_flush_all kernel/printk/printk.c:-1 [inline] console_unlock+0x223/0x630 kernel/printk/printk.c:2906 vprintk_emit+0x489/0x680 kernel/printk/printk.c:2303 _printk+0xcc/0x110 kernel/printk/printk.c:2328 br_set_state+0x45e/0x6f0 net/bridge/br_stp.c:57 br_init_port+0x95/0x200 net/bridge/br_stp_if.c:39 new_nbp+0x2f9/0x430 net/bridge/br_if.c:442 br_add_if+0x28b/0xec0 net/bridge/br_if.c:599 do_set_master net/core/rtnetlink.c:2630 [inline] rtnl_newlink_create net/core/rtnetlink.c:3439 [inline] __rtnl_newlink net/core/rtnetlink.c:3642 [inline] rtnl_newlink+0x1bdb/0x1ff0 net/core/rtnetlink.c:3655 rtnetlink_rcv_msg+0x79b/0xed0 net/core/rtnetlink.c:6153 netlink_rcv_skb+0x1de/0x420 net/netlink/af_netlink.c:2493 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x74c/0x8c0 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x89e/0xbc0 net/netlink/af_netlink.c:1859 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] ____sys_sendmsg+0x59b/0x970 net/socket.c:2519 ___sys_sendmsg+0x21c/0x290 net/socket.c:2573 __sys_sendmsg net/socket.c:2602 [inline] __do_sys_sendmsg net/socket.c:2611 [inline] __se_sys_sendmsg+0x19e/0x270 net/socket.c:2609 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f4dd238e969 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4dd3217038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f4dd25b5fa0 RCX: 00007f4dd238e969 RDX: 0000000000004000 RSI: 0000200000000280 RDI: 0000000000000003 RBP: 00007f4dd2410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f4dd25b5fa0 R15: 00007ffc29f18c88