rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P27201/1:b..l P27215/1:b..l P5486/1:b..l P19489/1:b..l P27177/2:b..l rcu: (detected by 0, t=10502 jiffies, g=113097, q=142 ncpus=2) task:syz.8.6057 state:R running task stack:24160 pid:27177 tgid:27176 ppid:19454 task_flags:0x40054c flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707 RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319 Code: 36 68 37 f6 90 0f 0b 90 90 90 eb c4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 31 c0 83 3d 77 c7 52 04 00 74 1e 83 3d 7a f6 52 04 00 RSP: 0018:ffffc9000b2a7128 EFLAGS: 00000293 RAX: ffffffff81f7b604 RBX: ffffffff81f7b4dc RCX: ffff88802e5c3c80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 0000000000000001 R08: ffffea0001b28d77 R09: 1ffffd40003651ae R10: dffffc0000000000 R11: fffff940003651af R12: dffffc0000000000 R13: fffffffffffffffe R14: ffffea0001b28d74 R15: 0000000000000001 rcu_read_unlock include/linux/rcupdate.h:895 [inline] page_ref_add_unless include/linux/page_ref.h:239 [inline] folio_ref_add_unless include/linux/page_ref.h:248 [inline] folio_try_get+0x149/0x340 include/linux/page_ref.h:264 find_get_entry mm/filemap.c:2082 [inline] find_lock_entries+0x24f/0xa60 mm/filemap.c:2172 shmem_undo_range+0x254/0x14b0 mm/shmem.c:1102 shmem_truncate_range mm/shmem.c:1232 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 task_work_run+0x1d4/0x260 kernel/task_work.c:227 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x6b5/0x2300 kernel/exit.c:966 do_group_exit+0x21c/0x2d0 kernel/exit.c:1107 get_signal+0x1285/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd597d8eec9 RSP: 002b:00007fd598c9b038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007fd597fe5fa0 RCX: 00007fd597d8eec9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000007 RBP: 00007fd597e11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd597fe6038 R14: 00007fd597fe5fa0 R15: 00007ffeee274f28 task:kworker/u8:1 state:R running task stack:21128 pid:19489 tgid:19489 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_mcast_mla_update Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7113 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7137 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 irq_work_queue+0xe0/0x140 kernel/irq_work.c:125 __kfence_alloc+0x27b/0x3b0 mm/kfence/core.c:1116 kfence_alloc include/linux/kfence.h:129 [inline] slab_alloc_node mm/slub.c:5226 [inline] __kmalloc_cache_noprof+0x5ea/0x6f0 mm/slub.c:5720 kmalloc_noprof include/linux/slab.h:957 [inline] batadv_mcast_mla_meshif_get_ipv4 net/batman-adv/multicast.c:402 [inline] batadv_mcast_mla_meshif_get net/batman-adv/multicast.c:529 [inline] __batadv_mcast_mla_update net/batman-adv/multicast.c:909 [inline] batadv_mcast_mla_update+0xf92/0x3640 net/batman-adv/multicast.c:946 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:dhcpcd state:R running task stack:21288 pid:5486 tgid:5486 ppid:5485 task_flags:0x400140 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__rcu_read_unlock+0x0/0xe0 kernel/rcu/tree_plugin.h:431 Code: 89 d9 80 e1 07 80 c1 03 38 c1 7c dc 48 89 df e8 36 9a 7e 00 eb d2 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 41 57 41 56 41 55 41 54 53 49 bf 00 00 00 00 00 fc ff RSP: 0018:ffffc90003d4f2f0 EFLAGS: 00000286 RAX: 2011df59b97c6900 RBX: ffffffff90d29d01 RCX: 2011df59b97c6900 RDX: 0000000000000003 RSI: ffffffff8d9d15ab RDI: ffffffff8bc074e0 RBP: dffffc0000000000 R08: ffffc90003d4ff38 R09: ffffc90003d4f418 R10: dffffc0000000000 R11: fffff520007a9e85 R12: ffffc90003d4ff48 R13: ffffc90003d48000 R14: ffffc90003d4f3c8 R15: ffffffff81731d25 rcu_read_unlock include/linux/rcupdate.h:899 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x19ae/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4947 [inline] slab_alloc_node mm/slub.c:5246 [inline] kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5253 vm_area_dup+0x2b/0x680 mm/vma_init.c:123 dup_mmap+0x903/0x1b10 mm/mmap.c:1780 dup_mm kernel/fork.c:1489 [inline] copy_mm+0x13c/0x4b0 kernel/fork.c:1541 copy_process+0x1706/0x3c00 kernel/fork.c:2181 kernel_clone+0x21e/0x840 kernel/fork.c:2609 __do_sys_clone kernel/fork.c:2750 [inline] __se_sys_clone kernel/fork.c:2734 [inline] __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2734 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f47cbb98636 RSP: 002b:00007fffa58c7030 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fffa58c7038 RCX: 00007f47cbb98636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fffa58e7580 R08: 0000000000000000 R09: 0000000000000001 R10: 00007f47cbac4a10 R11: 0000000000000246 R12: 00007fffa58c7170 R13: 0000000000000000 R14: 0000000000000000 R15: 0000558fbea95ac0 task:syz-executor state:R running task stack:26920 pid:27215 tgid:27215 ppid:19546 task_flags:0x400040 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:debug_lockdep_rcu_enabled+0x21/0x40 kernel/rcu/update.c:321 Code: 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 77 c7 52 04 00 74 1e 83 3d 7a f6 52 04 00 74 15 65 48 8b 0c 25 08 10 91 92 <31> c0 83 b9 2c 0b 00 00 00 0f 94 c0 e9 d9 f7 c4 f5 cc cc cc cc cc RSP: 0018:ffffc900040ef5f0 EFLAGS: 00000202 RAX: 0000000000000000 RBX: ffffffff823a0987 RCX: ffff888033688000 RDX: 0000000000000000 RSI: ffffffff8d9d15ab RDI: ffffffff8bc074e0 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff81731d25 R10: dffffc0000000000 R11: ffffffff81abbce0 R12: 1ffff9200081ded9 R13: ffffc900040ef700 R14: ffffc900040ef6c8 R15: ffffffff81731d25 rcu_read_lock include/linux/rcupdate.h:868 [inline] class_rcu_constructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0xcb/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587 kasan_save_free_info mm/kasan/kasan.h:406 [inline] poison_slab_object mm/kasan/common.c:252 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284 kasan_slab_free include/linux/kasan.h:234 [inline] slab_free_hook mm/slub.c:2515 [inline] slab_free mm/slub.c:6574 [inline] kfree+0x19a/0x6d0 mm/slub.c:6781 tomoyo_path_perm+0x36f/0x4b0 security/tomoyo/file.c:840 tomoyo_path_symlink+0xa3/0xe0 security/tomoyo/tomoyo.c:212 security_path_symlink+0x177/0x380 security/security.c:2023 do_symlinkat+0x107/0x3f0 fs/namei.c:4841 __do_sys_symlinkat fs/namei.c:4859 [inline] __se_sys_symlinkat fs/namei.c:4856 [inline] __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:4856 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe66338e447 RSP: 002b:00007ffe3c88b878 EFLAGS: 00000206 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe66338e447 RDX: 00007fe663413852 RSI: 00000000ffffff9c RDI: 00007ffe3c88b910 RBP: 00007ffe3c88b8bc R08: 0000000000000013 R09: 00007ffe3c88b5c7 R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000014e R13: 00000000000927c0 R14: 0000000000128a40 R15: 00007ffe3c88b910 task:syz.7.6065 state:R running task stack:25608 pid:27201 tgid:27198 ppid:20768 task_flags:0x400040 flags:0x00080001 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7256 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_release+0x2b5/0x3e0 kernel/locking/lockdep.c:5893 Code: 51 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 56 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 7b 1a f4 10 <48> 3b 44 24 28 0f 85 8b 00 00 00 48 83 c4 30 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000415f0f0 EFLAGS: 00000206 RAX: d33a5d5649a16e00 RBX: 0000000000000206 RCX: d33a5d5649a16e00 RDX: 0000000000000000 RSI: ffffffff8d9d15ab RDI: ffffffff8bc074e0 RBP: ffff888029820b30 R08: ffffc9000415f350 R09: ffffc9000415f278 R10: dffffc0000000000 R11: fffff5200082be51 R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8e13d320 R15: ffff888029820000 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] class_rcu_destructor include/linux/rcupdate.h:1195 [inline] unwind_next_frame+0x19a9/0x2390 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 save_stack+0xf5/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1394 [inline] free_unref_folios+0xdb3/0x14f0 mm/page_alloc.c:2963 folios_put_refs+0x584/0x670 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x49e/0x14b0 mm/shmem.c:1120 shmem_truncate_range mm/shmem.c:1232 [inline] shmem_evict_inode+0x272/0xa70 mm/shmem.c:1360 evict+0x504/0x9c0 fs/inode.c:810 __dentry_kill+0x209/0x660 fs/dcache.c:669 dput+0x19f/0x2b0 fs/dcache.c:911 __fput+0x68e/0xa70 fs/file_table.c:476 fput_close_sync+0x119/0x200 fs/file_table.c:573 __do_sys_close fs/open.c:1589 [inline] __se_sys_close fs/open.c:1574 [inline] __x64_sys_close+0x7f/0x110 fs/open.c:1574 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f053838db2a RSP: 002b:00007f0539169e00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f053838db2a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000005e14 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004 R13: 00007f0539169ef0 R14: 00007f0539169eb0 R15: 00007f052e000000 rcu: rcu_preempt kthread starved for 10573 jiffies! g113097 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:25960 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 2e 03 c5 f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d e3 f0 1c 00 f3 0f 1e fa fb f4 03 03 c5 f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c6 RAX: f5411d1f1e171600 RBX: ffffffff81960c17 RCX: f5411d1f1e171600 RDX: 0000000000000001 RSI: ffffffff8d7e8769 RDI: ffffffff8bc074e0 RBP: ffffffff8de07ea8 R08: ffff8880b8632fdb R09: 1ffff110170c65fb R10: dffffc0000000000 R11: ffffed10170c65fc R12: ffffffff8f9e0f70 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a40 FS: 0000000000000000(0000) GS:ffff888125d0f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fdebd225927 CR3: 00000000632d8000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147