rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4251/1:b..l (detected by 1, t=10503 jiffies, g=68377, q=100) task:kworker/u4:6 state:R running task stack:21264 pid: 4251 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet 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_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:ffffc900031ff900 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 8c6ab577fbbe5800 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f980 RBP: ffffc900031ffa20 R08: dffffc0000000000 R09: 1ffffffff203a818 R10: dffffc0000000000 R11: fffffbfff203a819 R12: ffffffff8c31eaa0 R13: 1ffff9200063ff2c R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:754 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:825 [inline] batadv_iv_ogm_schedule+0x432/0xec0 net/batman-adv/bat_iv_ogm.c:868 batadv_iv_send_outstanding_bat_ogm_packet+0x72f/0x840 net/batman-adv/bat_iv_ogm.c:1712 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 starved for 10389 jiffies! g68377 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27536 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10358 Comm: syz.5.1162 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:__sanitizer_cov_trace_pc+0x3e/0x60 kernel/kcov.c:211 Code: e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 34 16 00 00 00 74 2c 8b 91 10 16 00 00 83 fa 02 75 21 48 8b 91 18 16 00 00 <48> 8b 32 48 8d 7e 01 8b 89 14 16 00 00 48 39 cf 73 08 48 89 44 f2 RSP: 0018:ffffc90003f37a28 EFLAGS: 00000046 RAX: ffffffff816928ec RBX: 0000000000b3b3cc RCX: ffff88807e0bbb80 RDX: ffffc90012e4a000 RSI: 000001fb63109b96 RDI: 0000000000b3b3cc RBP: 000000000002043c R08: ffffffff8d89e36f R09: 1ffffffff1b13c6d R10: dffffc0000000000 R11: fffffbfff1b13c6e R12: ffffffffff4c4c33 R13: 0000015e4b7d3b87 R14: 1fffffffffffffff R15: 000001fb63109b96 FS: 00007ff4cf61a6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000058 CR3: 000000002143c000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: timekeeping_get_delta kernel/time/timekeeping.c:273 [inline] timekeeping_get_ns kernel/time/timekeeping.c:388 [inline] ktime_get+0x18c/0x270 kernel/time/timekeeping.c:831 clockevents_program_event+0xe2/0x310 kernel/time/clockevents.c:326 hrtimer_start_range_ns+0xa9a/0xc20 kernel/time/hrtimer.c:1287 posixtimer_rearm+0x131/0x340 kernel/time/posix-timers.c:329 dequeue_signal+0x174/0x440 kernel/signal.c:696 get_signal+0x6fe/0x12c0 kernel/signal.c:2781 arch_do_signal_or_restart+0xe7/0x12c0 arch/x86/kernel/signal.c:867 handle_signal_work kernel/entry/common.c:154 [inline] exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7ff4d13c0817 Code: 83 c8 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 RSP: 002b:00007ff4cf61a0e8 EFLAGS: 00000246 RAX: 00000000000000ca RBX: 00007ff4d1639fa8 RCX: 00007ff4d13c0819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff4d1639fa8 RBP: 00007ff4d1639fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff4d163a038 R14: 00007ffd0abe0a50 R15: 00007ffd0abe0b38