rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=ba24/1/0x4000000000000000 softirq=16107/16118 fqs=0
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5199/1:b..l
rcu: 	(detected by 1, t=10506 jiffies, g=11829, q=591 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5836 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__raw_callee_save___pv_queued_spin_unlock+0x10/0x18
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 52 b8 01 00 00 00 31 d2 f0 0f b0 17 <75> 06 5a c3 cc cc cc cc 56 0f b6 f0 e8 9f ff ff ff 5e 5a e9 98 3d
RSP: 0018:ffffc90000007bb8 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffff99abaf50 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff99abaf50
RBP: 1ffffffff33575eb R08: ffffffff99abaf53 R09: 1ffffffff33575ea
R10: dffffc0000000000 R11: fffffbfff33575eb R12: dffffc0000000000
R13: 1ffffffff33575ec R14: ffffffff99abaf60 R15: ffffffff99abaf58
FS:  00007faf16764880(0000) GS:ffff888125e35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000d038 CR3: 0000000073f3e000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 pv_queued_spin_unlock arch/x86/include/asm/paravirt.h:562 [inline]
 queued_spin_unlock arch/x86/include/asm/qspinlock.h:57 [inline]
 do_raw_spin_unlock+0x122/0x240 kernel/locking/spinlock_debug.c:142
 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_unlock_irqrestore+0x78/0x110 kernel/locking/spinlock.c:194
 debug_object_activate+0x318/0x540 lib/debugobjects.c:836
 debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
 debug_activate kernel/time/hrtimer.c:477 [inline]
 enqueue_hrtimer+0x30/0x380 kernel/time/hrtimer.c:1081
 __run_hrtimer kernel/time/hrtimer.c:1794 [inline]
 __hrtimer_run_queues+0x636/0xc30 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
 __sysvec_apic_timer_interrupt+0x102/0x3e0 arch/x86/kernel/apic/apic.c:1062
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x16c/0x340 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 d4 38 e0 10 <48> 3b 44 24 58 0f 85 e5 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000409f3b8 EFLAGS: 00000206
RAX: 01416eed4779a200 RBX: 0000000000000000 RCX: 01416eed4779a200
RDX: 00000000ef8fc95f RSI: ffffffff8d979282 RDI: ffffffff8bc08360
RBP: ffffffff81743f85 R08: ffffffff81743f85 R09: ffffffff8df41a20
R10: ffffc9000409f578 R11: ffffffff81ada120 R12: 0000000000000002
R13: ffffffff8df41a20 R14: 0000000000000000 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 class_rcu_constructor include/linux/rcupdate.h:1195 [inline]
 unwind_next_frame+0xc2/0x23d0 arch/x86/kernel/unwind_orc.c:495
 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:584
 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:2540 [inline]
 slab_free mm/slub.c:6668 [inline]
 kfree+0x1c0/0x660 mm/slub.c:6876
 tomoyo_realpath_from_path+0x598/0x5d0 security/tomoyo/realpath.c:286
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x213/0x4b0 security/tomoyo/file.c:822
 security_inode_getattr+0x12f/0x330 security/security.c:1869
 vfs_getattr fs/stat.c:259 [inline]
 vfs_statx_path fs/stat.c:299 [inline]
 vfs_statx+0x18e/0x550 fs/stat.c:356
 vfs_fstatat+0x118/0x170 fs/stat.c:375
 __do_sys_newfstatat fs/stat.c:542 [inline]
 __se_sys_newfstatat fs/stat.c:536 [inline]
 __x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf16111b0a
Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
RSP: 002b:00007ffd6f790ae8 EFLAGS: 00000206 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 0000558f2fd92a70 RCX: 00007faf16111b0a
RDX: 00007ffd6f790b10 RSI: 0000558f2fd92a70 RDI: 00000000ffffff9c
RBP: 0000558f2fd92a88 R08: 000000000001f070 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd6f791c35
R13: 00007ffd6f790ba0 R14: 0000558f2915e6d7 R15: 00007ffd6f791c30
 </TASK>
task:udevd           state:R  running task     stack:22712 pid:5199  tgid:5199  ppid:1      task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7190
 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893
Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 ba 06 e0 10 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3
RSP: 0018:ffffc90002ea7010 EFLAGS: 00000206
RAX: df7d9b93c5e0cc00 RBX: 0000000000000202 RCX: df7d9b93c5e0cc00
RDX: 0000000000000001 RSI: ffffffff8d979282 RDI: ffffffff8bc08360
RBP: ffff8880731366d8 R08: ffffc90002ea7630 R09: 0000000000000000
R10: ffffc90002ea7198 R11: fffff520005d4e35 R12: 0000000000000001
R13: 0000000000000001 R14: ffffffff8df41a20 R15: ffff888073135b80
 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+0x1ab1/0x23d0 arch/x86/kernel/unwind_orc.c:695
 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
 poison_kmalloc_redzone mm/kasan/common.c:397 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414
 kasan_kmalloc include/linux/kasan.h:262 [inline]
 __do_kmalloc_node mm/slub.c:5657 [inline]
 __kmalloc_noprof+0x41d/0x800 mm/slub.c:5669
 kmalloc_noprof include/linux/slab.h:961 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
 tomoyo_encode+0x28b/0x550 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x58d/0x5d0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x1c1/0x3b0 security/tomoyo/file.c:771
 security_file_open+0xb1/0x270 security/security.c:2636
 do_dentry_open+0x34e/0x1420 fs/open.c:939
 vfs_open+0x3b/0x340 fs/open.c:1094
 do_open fs/namei.c:4628 [inline]
 path_openat+0x340e/0x3dd0 fs/namei.c:4787
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf16115c3a
RSP: 002b:00007ffd6f792f28 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000558f2fddb490 RCX: 00007faf16115c3a
RDX: 0000000000090800 RSI: 0000558f2fd92030 RDI: 00000000ffffff9c
RBP: 0000558f2fd92030 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 0000558f2fd9d7b0
R13: 00000000000000ff R14: 0000558f29162be0 R15: 00007ffd6f7931b0
 </TASK>
rcu: rcu_preempt kthread starved for 10506 jiffies! g11829 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:27840 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x14bc/0x5000 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6960
 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+0x599/0xb30 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 UID: 0 PID: 5827 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xcd8/0x12b0 kernel/smp.c:877
Code: 01 31 ff e8 4a 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 f5 95 0b 00 eb 38 f3 90 42 0f b6 04 2b 84 c0 75 11 <41> f7 04 24 01 00 00 00 74 1e e8 d9 95 0b 00 eb e4 44 89 e1 80 e1
RSP: 0018:ffffc9000401f560 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff110170c856d RCX: ffff88807b2b1e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000401f6e0 R08: ffffffff8f822077 R09: 1ffffffff1f0440e
R10: dffffc0000000000 R11: fffffbfff1f0440f R12: ffff8880b8642b68
R13: dffffc0000000000 R14: ffff8880b873bb00 R15: 0000000000000000
FS:  000055557e094500(0000) GS:ffff888125f35000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001300 CR3: 0000000073ec8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
 flush_tlb_mm_range+0x6b1/0x1280 arch/x86/mm/tlb.c:1472
 dup_mmap+0x15fa/0x1b80 mm/mmap.c:1866
 dup_mm kernel/fork.c:1529 [inline]
 copy_mm+0x13c/0x4b0 kernel/fork.c:1581
 copy_process+0x165d/0x3950 kernel/fork.c:2221
 kernel_clone+0x21e/0x820 kernel/fork.c:2651
 __do_sys_clone kernel/fork.c:2792 [inline]
 __se_sys_clone kernel/fork.c:2776 [inline]
 __x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2776
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd87e985e93
Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffe841969d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd87e985e93
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055557e0947d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 000000000001592e R15: 00007ffe84196b70
 </TASK>