rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P7034/1:b..l P6552/1:b..l rcu: (detected by 1, t=10502 jiffies, g=23005, q=339 ncpus=2) task:udevd state:R running task stack:26120 pid:6552 ppid:5161 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:692 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:234 Code: f8 15 00 00 83 fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc 15 00 00 48 39 cf 73 08 48 89 3a 48 89 44 f2 08 0f 1f 00 f3 0f 1e fa 48 8b 04 24 65 48 8b 15 70 2e 7e 7e 65 8b RSP: 0018:ffffc900033a7620 EFLAGS: 00000293 RAX: ffffffff8192b8ad RBX: 00007f8bcc115527 RCX: ffff88802c613c00 RDX: 0000000000000000 RSI: ffffffff8afc66a0 RDI: ffffffff8afc6660 RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff21b46a0 R10: dffffc0000000000 R11: fffffbfff21b46a1 R12: ffffffff8a8000d0 R13: ffffc900033a7ae0 R14: 00007f8bcc115527 R15: 1ffff92000674ee2 rcu_read_lock include/linux/rcupdate.h:787 [inline] is_bpf_text_address+0x6d/0x2a0 kernel/bpf/core.c:741 kernel_text_address+0xa0/0xd0 kernel/extable.c:125 __kernel_text_address+0xd/0x30 kernel/extable.c:79 unwind_get_return_address+0x5d/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:45 [inline] kasan_set_track+0x4e/0x70 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1806 [inline] slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832 slab_free mm/slub.c:3816 [inline] __kmem_cache_free+0xba/0x1f0 mm/slub.c:3829 tomoyo_path_perm+0x3a0/0x4b0 security/tomoyo/file.c:842 tomoyo_path_symlink+0xa4/0xe0 security/tomoyo/tomoyo.c:211 security_path_symlink+0xe0/0x130 security/security.c:1786 do_symlinkat+0x108/0x3f0 fs/namei.c:4497 __do_sys_symlink fs/namei.c:4520 [inline] __se_sys_symlink fs/namei.c:4518 [inline] __x64_sys_symlink+0x7e/0x90 fs/namei.c:4518 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8bcc115527 RSP: 002b:00007ffcc4209728 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000563e8d1cfbc0 RCX: 00007f8bcc115527 RDX: fffffffffffffe68 RSI: 00007ffcc4209730 RDI: 0000563e8d1921d0 RBP: 00000000000002db R08: 0000000000000064 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffcc4209730 R13: 0000563e8d1a9420 R14: 0000000000000008 R15: 0000563e8d1cfbc0 task:kworker/u4:20 state:R running task stack:22728 pid:7034 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:7009 irqentry_exit+0x67/0x70 kernel/entry/common.c:438 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:lock_acquire+0x1f2/0x410 kernel/locking/lockdep.c:5758 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 04 3c 00 00 00 00 66 43 c7 44 3c 09 00 00 43 c6 44 3c 0b 00 RSP: 0018:ffffc9000b4a78a0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 3234166cd287fb00 RDX: 0000000000000000 RSI: ffffffff8aaacb40 RDI: ffffffff8afc66c0 RBP: ffffc9000b4a79a8 R08: dffffc0000000000 R09: 1ffffffff21b46a0 R10: dffffc0000000000 R11: fffffbfff21b46a1 R12: 1ffff92001694f20 R13: ffffffff8cd2fbe0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:334 [inline] rcu_read_lock include/linux/rcupdate.h:786 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:753 [inline] batadv_iv_ogm_schedule_buff net/batman-adv/bat_iv_ogm.c:824 [inline] batadv_iv_ogm_schedule+0x417/0xe90 net/batman-adv/bat_iv_ogm.c:867 batadv_iv_send_outstanding_bat_ogm_packet+0x731/0x840 net/batman-adv/bat_iv_ogm.c:1711 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: rcu_preempt kthread starved for 10577 jiffies! g23005 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:26920 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 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: 0 Comm: swapper/0 Not tainted 6.6.102-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:148 Code: cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d e3 e6 3a 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 66 0f 1f 00 55 41 57 41 56 RSP: 0018:ffffffff8ca07d80 EFLAGS: 000002c6 RAX: 4417a64157b6c100 RBX: ffffffff8161914b RCX: 4417a64157b6c100 RDX: 0000000000000001 RSI: ffffffff8aaab9c0 RDI: ffffffff8afc66c0 RBP: ffffffff8ca07eb8 R08: ffff8880b8e36d4b R09: 1ffff110171c6da9 R10: dffffc0000000000 R11: ffffed10171c6daa R12: ffffffff8e4a8828 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1952670 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c2b65b9 CR3: 000000002d8b8000 CR4: 00000000003506f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:753 default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97 cpuidle_idle_call kernel/sched/idle.c:170 [inline] do_idle+0x1eb/0x510 kernel/sched/idle.c:282 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380 rest_init+0x2e2/0x300 init/main.c:732 arch_call_rest_init+0xe/0x10 init/main.c:829 start_kernel+0x459/0x4e0 init/main.c:1074 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:555 x86_64_start_kernel+0x60/0x60 arch/x86/kernel/head64.c:536 secondary_startup_64_no_verify+0x179/0x17b