rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=5d9c/1/0x4000000000000000 softirq=59433/59433 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3006/1:b..l rcu: (detected by 0, t=10502 jiffies, g=48813, q=135 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12425 Comm: syz.1.1862 Not tainted 6.15.0-syzkaller-10820-gcd2e103d57e5 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:lock_release+0x0/0x2f0 kernel/locking/lockdep.c:5879 Code: 8b 4c 24 20 44 8b 44 24 1c 44 8b 4c 24 18 4c 8b 54 24 10 44 8b 5c 24 0c eb 8c 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 41 55 41 54 49 89 f4 53 48 89 fb 48 83 ec RSP: 0018:ffffc90000a08d88 EFLAGS: 00000046 RAX: 0000000080010001 RBX: 0000000000000001 RCX: ffffffff899032f7 RDX: ffff888030cc2440 RSI: ffffffff8990311c RDI: ffffffff8e5c4d80 RBP: ffff88803101cc00 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 185a7b7ddc000000 R13: 185a7b7ddc000000 R14: 0000000000000002 R15: ffff88803101d810 FS: 00007f01292cf6c0(0000) GS:ffff888124865000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000003e000 CR3: 000000002916b000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] advance_sched+0x6f1/0xc80 net/sched/sch_taprio.c:987 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x1ff/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:finish_task_switch.isra.0+0x22a/0xc10 kernel/sched/core.c:5260 Code: fb 09 00 00 44 8b 05 89 16 1e 0f 45 85 c0 0f 85 be 01 00 00 4c 89 e7 e8 a4 f6 ff ff e8 0f 03 3a 00 fb 65 48 8b 1d 3e e1 41 12 <48> 8d bb 18 16 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 RSP: 0018:ffffc900102376f8 EFLAGS: 00000202 RAX: 0000000000009631 RBX: ffff888030cc2440 RCX: ffffffff81c3d0df RDX: 0000000000000000 RSI: ffffffff8de092c5 RDI: ffffffff8c1544e0 RBP: ffffc90010237740 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff90a7b357 R11: 0000000000000001 R12: ffff8880b853bc40 R13: ffff888031568000 R14: 0000000000000001 R15: ffff8880b853cab0 context_switch kernel/sched/core.c:5395 [inline] __schedule+0x1172/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75 do_wait_for_common kernel/sched/completion.c:95 [inline] __wait_for_common+0x2ff/0x4e0 kernel/sched/completion.c:116 rdmsr_safe_on_cpu+0x1dc/0x210 arch/x86/lib/msr-smp.c:181 msr_read+0x19d/0x250 arch/x86/kernel/msr.c:66 vfs_read+0x1e4/0xc60 fs/read_write.c:570 ksys_read+0x12a/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f012838e969 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:00007f01292cf038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f01285b5fa0 RCX: 00007f012838e969 RDX: 0000000000019000 RSI: 0000200000032680 RDI: 0000000000000004 RBP: 00007f0128410ab1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f01285b5fa0 R15: 00007ffd58ae2488 task:kworker/u8:8 state:R running task stack:23544 pid:3006 tgid:3006 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 preempt_schedule_notrace+0x62/0xe0 kernel/sched/core.c:7054 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:746 rcu_read_unlock include/linux/rcupdate.h:869 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:779 [inline] batadv_iv_ogm_schedule_buff+0xa4d/0x14e0 net/batman-adv/bat_iv_ogm.c:833 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:876 [inline] batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:869 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x329/0x920 net/batman-adv/bat_iv_ogm.c:1720 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g48813 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=41686 rcu: rcu_preempt kthread starved for 10502 jiffies! g48813 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27784 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5392 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6781 __schedule_loop kernel/sched/core.c:6859 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6874 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c5/0x780 kernel/kthread.c:464 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245