rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4508/1:b..l P5200/1:b..l rcu: (detected by 0, t=10506 jiffies, g=22521, q=129 ncpus=2) task:udevd state:R running task stack:22600 pid:5200 tgid:5200 ppid:1 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:list_empty include/linux/list.h:373 [inline] RIP: 0010:waitqueue_active include/linux/wait.h:127 [inline] RIP: 0010:wq_has_sleeper include/linux/wait.h:161 [inline] RIP: 0010:skwq_has_sleeper include/net/sock.h:2330 [inline] RIP: 0010:unix_write_space+0x1e0/0x470 net/unix/af_unix.c:601 Code: 74 5a e8 23 06 0b f7 eb 05 e8 1c 06 0b f7 4d 85 e4 74 42 f0 83 44 24 fc 00 49 8d 5c 24 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 <74> 08 48 89 df e8 d6 ae 72 f7 48 8b 03 48 39 d8 74 4c e8 e9 05 0b RSP: 0018:ffffc90002fe7788 EFLAGS: 00000246 RAX: 1ffff110047479d0 RBX: ffff888023a3ce80 RCX: ffff88807fe79e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000008 R08: ffffffff8ab7b634 R09: 1ffff110068a9683 R10: dffffc0000000000 R11: ffffed10068a9684 R12: ffff888023a3ce40 R13: ffff88803454b180 R14: ffffffff8ab7b4a6 R15: dffffc0000000000 sock_wfree+0x1dd/0x7b0 net/core/sock.c:2629 unix_destruct_scm+0x1d5/0x220 net/unix/af_unix.c:1869 skb_release_head_state+0x100/0x250 net/core/skbuff.c:1149 skb_release_all net/core/skbuff.c:1160 [inline] __kfree_skb net/core/skbuff.c:1176 [inline] consume_skb+0x60/0xf0 net/core/skbuff.c:1408 __unix_dgram_recvmsg+0xced/0x12e0 net/unix/af_unix.c:2505 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg+0x22f/0x280 net/socket.c:1039 ____sys_recvmsg+0x1c8/0x480 net/socket.c:2786 ___sys_recvmsg net/socket.c:2828 [inline] __sys_recvmsg+0x2a5/0x3a0 net/socket.c:2861 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f880f72491e RSP: 002b:00007ffd82ee6e28 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f880f72491e RDX: 0000000000000040 RSI: 00007ffd82ee6ef0 RDI: 0000000000000009 RBP: 00007ffd82ee6ef0 R08: 0000000015f27dd1 R09: 7fffffffffffffff R10: 00007f880fb82038 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000200000001 R14: 0000000000000000 R15: 0000000000000000 task:kworker/u8:8 state:R running task stack:22536 pid:4508 tgid:4508 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 preempt_schedule_irq+0xfe/0x1c0 kernel/sched/core.c:7090 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:lock_release+0x244/0x3e0 arch/x86/include/asm/irqflags.h:-1 Code: 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 0f 85 c3 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 03 <48> 3b 44 24 28 0f 85 82 01 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000d677a50 EFLAGS: 00000206 RAX: 7aa9e075c520bb00 RBX: ffffffff93651020 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff8e4c80af RDI: ffffffff8ca0e280 RBP: ffff888033bb0b40 R08: ffffffff8bf1b94e R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002 R13: ffff888033bb0000 R14: 0000000000000206 R15: ffffffff8ed3df20 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x28b/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac3/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g22521 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=24586 rcu: rcu_preempt kthread starved for 10506 jiffies! g22521 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:26688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b33/0x51f0 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b7/0x940 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:153 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: 0 Comm: swapper/1 Not tainted 6.15.0-rc3-syzkaller-00008-ga33b5a08cbbd #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lock_acquire+0x152/0x2f0 kernel/locking/lockdep.c:5869 Code: ff ff ff 65 0f c1 05 9d e4 c6 11 83 f8 01 0f 85 f9 00 00 00 48 c7 44 24 10 00 00 00 00 9c 8f 44 24 10 f7 44 24 10 00 02 00 00 <0f> 85 fd 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 65 48 8b 45 00 48 RSP: 0018:ffffc90000a08c20 EFLAGS: 00000046 RAX: 0000000000000001 RBX: ffff8880b87276d8 RCX: 265670e0e110a000 RDX: 0000000000000001 RSI: ffffffff8e4c80af RDI: ffffffff8ca0e280 RBP: ffffffff93651020 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000046 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881250cf000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000021000 CR3: 000000005cb0c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xd3/0x120 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1765 [inline] __hrtimer_run_queues+0x67b/0xd40 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 6e 20 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197dc0 EFLAGS: 000002c6 RAX: 265670e0e110a000 RBX: ffffffff8197267e RCX: ffffffff8c27c89c RDX: 0000000000000001 RSI: ffffffff8e635648 RDI: ffffffff8ca0e280 RBP: ffffc90000197f20 R08: ffff8880b8732b5b R09: 1ffff110170e656b R10: dffffc0000000000 R11: ffffed10170e656c R12: 1ffff92000032fd2 R13: 1ffff11003ad8b40 R14: 0000000000000001 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:748 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:185 [inline] do_idle+0x22e/0x5d0 kernel/sched/idle.c:325 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:423 start_secondary+0xfe/0x100 arch/x86/kernel/smpboot.c:315 common_startup_64+0x13e/0x147