rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4596/1:b..l (detected by 0, t=10502 jiffies, g=49461, q=167 ncpus=2) task:kworker/u4:14 state:R running task stack:21544 pid:4596 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_reschedule_ipi+0x16/0x20 arch/x86/include/asm/idtentry.h:696 RIP: 0010:lock_acquire+0x20f/0x490 kernel/locking/lockdep.c:5666 Code: 00 9c 8f 84 24 80 00 00 00 f6 84 24 81 00 00 00 02 0f 85 f5 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 66 43 c7 44 3d 09 00 00 43 c6 44 3d 0b RSP: 0018:ffffc90005e97920 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 08d32ddaceca2800 RDX: 0000000000000000 RSI: ffffffff8a6c0f80 RDI: ffffffff8abf0da0 RBP: ffffc90005e97a28 R08: dffffc0000000000 R09: fffffbfff2117049 R10: fffffbfff2117049 R11: 1ffffffff2117048 R12: 0000000000000000 R13: 1ffff92000bd2f30 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [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+0x413/0xe90 net/batman-adv/bat_iv_ogm.c:868 batadv_iv_send_outstanding_bat_ogm_packet+0x72d/0x840 net/batman-adv/bat_iv_ogm.c:1712 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 rcu: rcu_preempt kthread starved for 10526 jiffies! g49461 f0x0 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: 8494 Comm: syz.3.955 Not tainted 6.1.138-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025 RIP: 0010:unwind_next_frame+0x66b/0x20b0 arch/x86/kernel/unwind_orc.c:475 Code: 28 84 c0 0f 85 e3 15 00 00 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 0f 85 ef 15 00 00 49 0f bf 04 24 48 01 c5 e9 fa 00 00 00 <4c> 8d 7b 40 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 RSP: 0018:ffffc9001228f590 EFLAGS: 00000093 RAX: 0000000000000014 RBX: ffffc9001228f6c8 RCX: ffffffff8e0d10a4 RDX: ffffffff8e7bda9c RSI: ffffffff8e0d10a0 RDI: 0000000000000001 RBP: ffffffff8e7bdaa0 R08: 0000000000000001 R09: ffffc9001228f718 R10: fffff52002451ee5 R11: 1ffff92002451ee3 R12: ffffffff8e7bda9c R13: dffffc0000000000 R14: ffffffff8e0d10a0 R15: 0000000000000004 FS: 00007fb7a3dff6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000057f51000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __unwind_start+0x5bb/0x740 arch/x86/kernel/unwind_orc.c:717 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xda/0x140 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:177 [inline] slab_free_hook mm/slub.c:1724 [inline] slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1750 slab_free mm/slub.c:3661 [inline] kmem_cache_free+0xf7/0x290 mm/slub.c:3683 __sigqueue_free kernel/signal.c:459 [inline] collect_signal kernel/signal.c:602 [inline] __dequeue_signal+0x4e9/0x610 kernel/signal.c:624 dequeue_signal+0xe5/0x4b0 kernel/signal.c:647 get_signal+0x547/0x1350 kernel/signal.c:2751 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb7a3f8e969 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:00007fb7a3dff0e8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: 00007fb7a41b5fa8 RCX: 00007fb7a3f8e969 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fb7a41b5fac RBP: 00007fb7a41b5fa0 R08: 001ed030f54bf444 R09: 0000000000000000 R10: 0000200000000000 R11: 0000000000000246 R12: 00007fb7a41b5fac R13: 0000000000000000 R14: 00007fff9506aed0 R15: 00007fff9506afb8