rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6164/1:b..l P6178/1:b..l P3552/1:b..l P5819/1:b..l P5189/1:b..l rcu: (detected by 0, t=10502 jiffies, g=12625, q=1514 ncpus=2) task:udevd state:R running task stack:24928 pid:5189 tgid:5189 ppid:1 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_read_lock include/linux/rcupdate.h:851 [inline] RIP: 0010:class_rcu_constructor include/linux/rcupdate.h:1193 [inline] RIP: 0010:unwind_next_frame+0xc6/0x23c0 arch/x86/kernel/unwind_orc.c:495 Code: 34 00 4c 8d 3d 00 00 00 00 48 c7 c7 e0 03 76 8e 31 f6 31 d2 b9 02 00 00 00 45 31 c0 45 31 c9 41 57 e8 9e f7 2a 00 48 83 c4 08 95 5d 35 0a 85 c0 74 3a e8 cc 21 34 00 84 c0 75 31 e8 83 5d 35 RSP: 0018:ffffc90003b173d8 EFLAGS: 00000286 RAX: 29eaf6c3e34c2b00 RBX: ffffffff822f574e RCX: 0000000000000046 RDX: 0000000096cd8dd3 RSI: ffffffff8e15c5bc RDI: ffffffff8c279800 RBP: dffffc0000000000 R08: ffffffff81767a45 R09: ffffffff8e7603e0 R10: dffffc0000000000 R11: ffffffff81b0a7f0 R12: 1ffff92000762e95 R13: ffffc90003b174e0 R14: ffffc90003b174a8 R15: ffffffff81767a45 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584 poison_slab_object mm/kasan/common.c:253 [inline] __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285 kasan_slab_free include/linux/kasan.h:235 [inline] slab_free_hook mm/slub.c:2670 [inline] slab_free mm/slub.c:6082 [inline] kfree+0x1c1/0x630 mm/slub.c:6399 tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x283/0x560 security/tomoyo/file.c:827 security_inode_getattr+0x12b/0x310 security/security.c:1869 vfs_getattr+0x23/0x70 fs/stat.c:259 vfs_statx_path+0x2b/0x230 fs/stat.c:299 vfs_statx+0x12e/0x200 fs/stat.c:356 vfs_fstatat+0x11b/0x170 fs/stat.c:373 __do_sys_newfstatat fs/stat.c:538 [inline] __se_sys_newfstatat fs/stat.c:532 [inline] __x64_sys_newfstatat+0x151/0x200 fs/stat.c:532 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7efcc1d11b0a RSP: 002b:00007ffd25fcb4f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 000055ee5d010410 RCX: 00007efcc1d11b0a RDX: 00007ffd25fcb500 RSI: 000055ee5cffe2a8 RDI: 00000000ffffff9c RBP: 000055ee69ea6148 R08: 00063478c1c69200 R09: 3fffffffffffffff R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd25fcb500 R14: 0000000000000000 R15: 00063478c1c69200 task:syz-executor state:R running task stack:22464 pid:5819 tgid:5819 ppid:5816 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:81 [inline] RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:103 [inline] RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:238 [inline] RIP: 0010:unwind_next_frame+0x513/0x23c0 arch/x86/kernel/unwind_orc.c:510 Code: c1 e8 3f 48 01 c8 48 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 <84> c0 75 27 49 63 07 4c 01 f8 49 8d 4f 04 4c 39 e0 48 0f 46 e9 49 RSP: 0018:ffffc900037f7198 EFLAGS: 00000212 RAX: 0000000000000000 RBX: ffffffff9028fe0c RCX: dffffc0000000000 RDX: ffffffff9028fe04 RSI: ffffffff90a4ac70 RDI: ffffffff8c2797a0 RBP: ffffffff9028fe04 R08: 0000000000000007 R09: ffffffff8e7603e0 R10: dffffc0000000000 R11: fffff520006fee65 R12: ffffffff816d0f72 R13: ffffffff9028fe04 R14: ffffc900037f72c8 R15: ffffffff9028fe08 __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1432 [inline] free_unref_folios+0xd38/0x14c0 mm/page_alloc.c:3039 folios_put_refs+0x789/0x8d0 mm/swap.c:1002 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149 shmem_truncate_range mm/shmem.c:1277 [inline] shmem_evict_inode+0x240/0x9e0 mm/shmem.c:1407 evict+0x61e/0xb10 fs/inode.c:846 filename_unlinkat+0x43f/0x610 fs/namei.c:5544 __do_sys_unlink fs/namei.c:5575 [inline] __se_sys_unlink+0x2e/0x140 fs/namei.c:5572 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb1af79b067 RSP: 002b:00007ffc3e3caa78 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb1af79b067 RDX: 00007ffc3e3caaa0 RSI: 00007ffc3e3cab30 RDI: 00007ffc3e3cab30 RBP: 00007ffc3e3cab30 R08: 00007ffc3e3cbb30 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffc3e3cbbc0 R13: 00007fb1af831c3b R14: 0000000000019dd6 R15: 00007ffc3e3cbc00 task:kworker/u8:12 state:R running task stack:22272 pid:3552 tgid:3552 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 a5 5e 0a 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 21 9c 79 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 f1 cc 6e ff cc 48 8d 3d 1e 2c 73 RSP: 0018:ffffc9000e01f498 EFLAGS: 00000282 RAX: 00d82b825329a500 RBX: 0000000000000246 RCX: 0000000000000046 RDX: 00000000af952914 RSI: ffffffff8e15c5bc RDI: ffffffff8c279800 RBP: 0000000000000000 R08: ffffffff81767a45 R09: ffffffff8e7603e0 R10: dffffc0000000000 R11: fffff52001c03ecd R12: 0000000000000002 R13: ffffffff8e7603e0 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 __unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:773 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:57 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4459 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4795 skb_clone+0x212/0x3a0 net/core/skbuff.c:2120 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:386 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:419 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x5b7/0x7e0 net/batman-adv/bat_iv_ogm.c:1697 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:syz.3.55 state:R running task stack:24640 pid:6178 tgid:6171 ppid:5828 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7234 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_acquire+0x20b/0x2e0 kernel/locking/lockdep.c:5872 Code: e9 30 ff ff ff e8 a5 5e 0a 0a f7 c3 00 02 00 00 0f 84 38 ff ff ff 65 48 8b 05 21 9c 79 11 48 3b 44 24 30 75 33 fb 48 83 c4 38 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 f1 cc 6e ff cc 48 8d 3d 1e 2c 73 RSP: 0018:ffffc90003ae6cf8 EFLAGS: 00000282 RAX: 653ddfa220d90500 RBX: 0000000000000246 RCX: 0000000000000046 RDX: 00000000b0f12c24 RSI: ffffffff8e15c5bc RDI: ffffffff8c279800 RBP: 0000000000000000 R08: ffffffff81767a45 R09: ffffffff8e7603e0 R10: dffffc0000000000 R11: ffffffff81b0a7f0 R12: 0000000000000002 R13: ffffffff8e7603e0 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xc2/0x23c0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:341 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x231/0x280 mm/page_alloc.c:1888 prep_new_page mm/page_alloc.c:1896 [inline] get_page_from_freelist+0x24dc/0x2580 mm/page_alloc.c:3961 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5249 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2485 folio_alloc_mpol_noprof+0x39/0x70 mm/mempolicy.c:2504 shmem_alloc_folio mm/shmem.c:1930 [inline] shmem_alloc_and_add_folio+0x445/0xf80 mm/shmem.c:1972 shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2567 shmem_fault+0x179/0x390 mm/shmem.c:2768 __do_fault+0x138/0x390 mm/memory.c:5355 do_read_fault mm/memory.c:5790 [inline] do_fault mm/memory.c:5924 [inline] do_pte_missing+0x228f/0x3750 mm/memory.c:4469 handle_pte_fault mm/memory.c:6308 [inline] __handle_mm_fault mm/memory.c:6446 [inline] handle_mm_fault+0x1bec/0x3310 mm/memory.c:6615 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x165b/0x29d0 mm/gup.c:1428 populate_vma_page_range+0x2be/0x3c0 mm/gup.c:1860 __mm_populate+0x25f/0x390 mm/gup.c:1963 mm_populate include/linux/mm.h:3689 [inline] vm_mmap_pgoff+0x3aa/0x4f0 mm/util.c:586 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff52439bf79 RSP: 002b:00007ff525317028 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007ff524616090 RCX: 00007ff52439bf79 RDX: 0000000002000004 RSI: 0000000000c00000 RDI: 0000200000001000 RBP: 00007ff5244327e0 R08: ffffffffffffffff R09: 0000000000000000 R10: 000000000003b071 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ff524616128 R14: 00007ff524616090 R15: 00007ffec2babb88 task:syz.0.46 state:R running task stack:26120 pid:6164 tgid:6132 ppid:5822 task_flags:0x40054c flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7091 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] zap_pte_range mm/memory.c:1946 [inline] zap_pmd_range mm/memory.c:2008 [inline] zap_pud_range mm/memory.c:2036 [inline] zap_p4d_range mm/memory.c:2057 [inline] unmap_page_range+0x3b71/0x48f0 mm/memory.c:2078 unmap_single_vma mm/memory.c:2120 [inline] unmap_vmas+0x3c0/0x5c0 mm/memory.c:2162 exit_mmap+0x261/0xdb0 mm/mmap.c:1277 __mmput+0x118/0x430 kernel/fork.c:1174 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x62e/0x2310 kernel/exit.c:959 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0f8219bf79 RSP: 002b:00007f0f803f60e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f0f82416188 RCX: 00007f0f8219bf79 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f0f82416188 RBP: 00007f0f82416180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0f82416218 R14: 00007fff48122210 R15: 00007fff481222f8 rcu: rcu_preempt kthread starved for 2631 jiffies! g12625 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:28128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5340 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 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 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 7e 6e 02 e9 8e 72 64 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 43 8d 1d 00 fb f4 67 72 64 f5 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e407dc0 EFLAGS: 00000246 RAX: 00000000001c812b RBX: ffffffff819a779d RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8deed5ed RDI: ffffffff8c279800 RBP: ffffffff8e407eb0 R08: ffff8880b863395b R09: 1ffff110170c672b R10: dffffc0000000000 R11: ffffed10170c672c R12: ffffffff90114db0 R13: 1ffffffff1c929d8 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88812546f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f01984949a9 CR3: 000000005073f000 CR4: 0000000000350ef0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1bd/0x500 kernel/sched/idle.c:332 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:760 start_kernel+0x385/0x3d0 init/main.c:1210 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