rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5140/1:b..l P16415/1:b..l P25023/1:b..l rcu: (detected by 0, t=10502 jiffies, g=206225, q=429 ncpus=1) task:syz-executor state:R running task stack:24360 pid:25023 ppid:5763 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6868 preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6892 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45 unwind_next_frame+0x201c/0x2990 arch/x86/kernel/unwind_orc.c:672 arch_stack_walk+0x144/0x190 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 discard_slab mm/slub.c:2127 [inline] __unfreeze_partials+0x1cf/0x210 mm/slub.c:2667 put_cpu_partial+0x17c/0x250 mm/slub.c:2743 __slab_free+0x319/0x400 mm/slub.c:3700 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:306 kasan_slab_alloc include/linux/kasan.h:188 [inline] slab_post_alloc_hook+0x6a/0x4d0 mm/slab.h:770 slab_alloc_node mm/slub.c:3495 [inline] slab_alloc mm/slub.c:3503 [inline] __kmem_cache_alloc_lru mm/slub.c:3510 [inline] kmem_cache_alloc+0x17e/0x2c0 mm/slub.c:3519 kmem_cache_zalloc include/linux/slab.h:711 [inline] lsm_file_alloc security/security.c:625 [inline] security_file_alloc+0x34/0x120 security/security.c:2640 init_file+0x94/0x1f0 fs/file_table.c:179 alloc_empty_file+0xb7/0x1d0 fs/file_table.c:228 path_openat+0x120/0x3270 fs/namei.c:3830 do_filp_open+0x1f2/0x430 fs/namei.c:3871 do_sys_openat2+0x134/0x1d0 fs/open.c:1422 do_sys_open fs/open.c:1437 [inline] __do_sys_openat fs/open.c:1453 [inline] __se_sys_openat fs/open.c:1448 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1448 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f8b1df592d7 RSP: 002b:00007ffd84660c70 EFLAGS: 00000202 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000555566ea6500 RCX: 00007f8b1df592d7 RDX: 0000000000000002 RSI: 00007f8b1e034733 RDI: ffffffffffffff9c RBP: 00007f8b1e2265d8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000003 R14: 00007ffd84660f68 R15: 0000000000000000 task:syz-executor state:R running task stack:21800 pid:16415 ppid:1 flags:0x00004006 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011 irqentry_exit+0x67/0x70 kernel/entry/common.c:441 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:211 Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d fc d3 04 0d 48 89 de 5b e9 f3 d6 57 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 40 27 7c 7e 65 8b 15 41 27 7c 7e 81 e2 00 01 ff 00 74 RSP: 0018:ffffc900033d7580 EFLAGS: 00000202 RAX: ffffffff813322f2 RBX: ffffc900033d7640 RCX: ffff888025065a00 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000 RBP: ffffc900033d7610 R08: ffff888025065a00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff81d27f57 R13: 1ffff11004a0cbef R14: ffffffff81762b60 R15: ffffc900033d7588 arch_stack_walk+0x152/0x190 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 vfree+0x1a7/0x340 mm/vmalloc.c:2899 kcov_put kernel/kcov.c:440 [inline] kcov_close+0x2b/0x50 kernel/kcov.c:536 __fput+0x221/0x940 fs/file_table.c:418 task_work_run+0x1d4/0x260 kernel/task_work.c:245 exit_task_work include/linux/task_work.h:43 [inline] do_exit+0x986/0x2530 kernel/exit.c:890 do_group_exit+0x22d/0x2f0 kernel/exit.c:1032 get_signal+0x12a6/0x1390 kernel/signal.c:2915 arch_do_signal_or_restart+0xc2/0x7b0 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline] syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f6bfdd5e98e RSP: 002b:00007fffcbfb0c28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000555561806500 RCX: 00007f6bfdd5e98e RDX: 0000000000000030 RSI: 00007fffcbfb0d20 RDI: 00000000000000f9 RBP: 00007fffcbfb0ccc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000025c R13: 00000000000927c0 R14: 0000000000205c79 R15: 00007fffcbfb0d20 task:udevd state:R running task stack:23176 pid:5140 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7011 irqentry_exit+0x67/0x70 kernel/entry/common.c:441 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:__sanitizer_cov_trace_pc+0x5c/0x60 kernel/kcov.c:230 Code: 00 16 00 00 83 fa 02 75 21 48 8b 91 08 16 00 00 48 8b 32 48 8d 7e 01 8b 89 04 16 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 e0 26 7c 7e 65 8b RSP: 0018:ffffc900032c7458 EFLAGS: 00000293 RAX: ffffffff813bb2a1 RBX: ffffc900032c74d0 RCX: ffff88807e693c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffff88807e693c00 R09: 0000000000000003 R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff83ed8023 R13: 1ffff1100fcd282f R14: dffffc0000000000 R15: 1ffff92000658e9a unwind_get_return_address+0x71/0xc0 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0x11d/0x190 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0xaa/0x100 kernel/stacktrace.c:122 save_stack+0x125/0x230 mm/page_owner.c:128 __reset_page_owner+0x4e/0x190 mm/page_owner.c:149 reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1182 [inline] free_unref_page_prepare+0x7d7/0x8f0 mm/page_alloc.c:2366 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2459 __slab_free+0x35a/0x400 mm/slub.c:3736 qlink_free mm/kasan/quarantine.c:166 [inline] qlist_free_all+0x75/0xd0 mm/kasan/quarantine.c:185 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292 ____kasan_kmalloc mm/kasan/common.c:341 [inline] __kasan_kmalloc+0x22/0xa0 mm/kasan/common.c:384 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc+0xb7/0x240 mm/slab_common.c:1020 kmalloc include/linux/slab.h:604 [inline] tomoyo_realpath_from_path+0xe6/0x5c0 security/tomoyo/realpath.c:251 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x282/0x560 security/tomoyo/file.c:822 security_inode_getattr+0xd3/0x120 security/security.c:2190 vfs_getattr fs/stat.c:173 [inline] vfs_statx+0x172/0x680 fs/stat.c:248 vfs_fstatat+0x12a/0x1b0 fs/stat.c:299 __do_sys_newfstatat fs/stat.c:463 [inline] __se_sys_newfstatat fs/stat.c:457 [inline] __x64_sys_newfstatat+0x149/0x1f0 fs/stat.c:457 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe88a111b0a RSP: 002b:00007ffeed98f9a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 00005580bf49c410 RCX: 00007fe88a111b0a RDX: 00007ffeed98f9b0 RSI: 00005580bf48a2a8 RDI: 00000000ffffff9c RBP: 00005580eecfa148 R08: 00063478c1c69200 R09: 0000000000745bdb R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffeed98f9b0 R14: 0000000000000000 R15: 00063478c1c69200 rcu: rcu_preempt kthread starved for 9439 jiffies! g206225 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:26824 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x15ae/0x4660 kernel/sched/core.c:6701 schedule+0xbd/0x170 kernel/sched/core.c:6775 schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x9d/0x3b0 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: CPU: 0 PID: 3382 Comm: kworker/R-bat_e Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Workqueue: bat_events batadv_tt_purge RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xc0/0x120 kernel/locking/spinlock.c:194 Code: c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 41 c6 04 07 f8 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 ab 96 c0 f6 65 8b 05 1c 54 67 75 85 c0 74 3c 48 c7 04 24 0e 36 RSP: 0018:ffffc900000079a0 EFLAGS: 00000206 RAX: dffffc0000000004 RBX: 0000000000000a02 RCX: 07d1c0d79158dc00 RDX: dffffc0000000000 RSI: ffffffff8acacce0 RDI: 0000000000000001 RBP: ffffc90000007a30 R08: ffffffff911f0607 R09: 1ffffffff223e0c0 R10: dffffc0000000000 R11: fffffbfff223e0c1 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff888142fb8000 R15: 1ffff92000000f34 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f456f0688d2 CR3: 00000000770a8000 CR4: 00000000003506f0 Call Trace: spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] dummy_timer+0x3170/0x34e0 drivers/usb/gadget/udc/dummy_hcd.c:-1 __run_hrtimer kernel/time/hrtimer.c:1754 [inline] __hrtimer_run_queues+0x525/0xc10 kernel/time/hrtimer.c:1818 hrtimer_run_softirq+0x177/0x290 kernel/time/hrtimer.c:1835 handle_softirqs+0x27d/0x820 kernel/softirq.c:578 do_softirq+0xfa/0x1a0 kernel/softirq.c:479 __local_bh_enable_ip+0x184/0x1c0 kernel/softirq.c:406 spin_unlock_bh include/linux/spinlock.h:396 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2359 [inline] batadv_tt_purge+0x4b5/0xa20 net/batman-adv/translation-table.c:3633 process_one_work kernel/workqueue.c:2657 [inline] process_scheduled_works+0xa60/0x1600 kernel/workqueue.c:2734 rescuer_thread+0x71e/0x1080 kernel/workqueue.c:2931 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