rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4291/1:b..l (detected by 0, t=10502 jiffies, g=65757, q=355) task:kworker/u4:9 state:R running task stack:23312 pid: 4291 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:681 RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc900031efaa0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 77b9737b84051200 RDX: 0000000000000000 RSI: ffffffff8a2b43a0 RDI: ffffffff8a7a0700 RBP: ffffc900031efbc0 R08: dffffc0000000000 R09: 1ffffffff203ac18 R10: dffffc0000000000 R11: fffffbfff203ac19 R12: ffffffff8c31f320 R13: 1ffff9200063df60 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0xc9/0x5c0 net/batman-adv/network-coding.c:723 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread timer wakeup didn't happen for 10496 jiffies! g65757 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=26879 rcu: rcu_preempt kthread starved for 10497 jiffies! g65757 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:26960 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 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: 11138 Comm: syz.2.1529 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:rb_erase_cached include/linux/rbtree.h:124 [inline] RIP: 0010:timerqueue_del+0x9b/0x100 lib/timerqueue.c:57 Code: 07 e8 d9 17 72 fd eb 26 e8 d2 17 72 fd 4c 89 f7 e8 0a 71 ff ff 43 80 3c 2f 00 74 0e 4c 89 e7 49 89 c7 e8 08 37 b7 fd 4c 89 f8 <49> 89 04 24 4c 89 f7 48 89 de e8 76 5a ff ff 42 80 7c 2d 00 00 74 RSP: 0018:ffffc90000dd0d08 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff8880b912a390 RCX: ffff888022e4bb80 RDX: 0000000000010000 RSI: ffff88802b591340 RDI: ffff88802b591340 RBP: 1ffff110056b2268 R08: ffff88802b591357 R09: ffff88802b591340 R10: dffffc0000000000 R11: ffffed10056b226b R12: ffff8880b912a398 R13: dffffc0000000000 R14: ffff88802b591340 R15: 1ffff11017225473 FS: 00007f1651a506c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000020000001a000 CR3: 00000000641f7000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __remove_hrtimer kernel/time/hrtimer.c:1102 [inline] __run_hrtimer kernel/time/hrtimer.c:1665 [inline] __hrtimer_run_queues+0x366/0xb70 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc90003c37a60 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 91ae31a11e3c7d00 RDX: 0000000000000000 RSI: ffffffff8a2b43a0 RDI: ffffffff8a7a0700 RBP: ffffc90003c37b80 R08: dffffc0000000000 R09: 1ffffffff203ac1e R10: dffffc0000000000 R11: fffffbfff203ac1f R12: ffff88807e5f6a28 R13: 1ffff92000786f58 R14: 0000000000000246 R15: dffffc0000000000 __might_fault+0xb3/0x110 mm/memory.c:5357 _copy_to_user+0x29/0x130 lib/usercopy.c:35 copy_to_user include/linux/uaccess.h:200 [inline] msr_read+0x127/0x1b0 arch/x86/kernel/msr.c:70 vfs_read+0x301/0xd60 fs/read_write.c:483 ksys_read+0x152/0x260 fs/read_write.c:623 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1653817e59 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:00007f1651a50028 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007f1653a91090 RCX: 00007f1653817e59 RDX: 0000000000018ff8 RSI: 0000200000019680 RDI: 0000000000000005 RBP: 00007f16538add6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1653a91128 R14: 00007f1653a91090 R15: 00007ffe6e2a3f78