syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P21943/2:b..l P1157/1:b..l P5195/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=114961, q=464 ncpus=2)
task:udevd           state:R  running task     stack:24744 pid:5195  tgid:5195  ppid:1      task_flags:0x400140 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6855
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7182
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x58c/0x20a0 arch/x86/kernel/unwind_orc.c:512
Code: 9e c6 84 d2 0f 95 c2 40 84 d6 0f 85 ee 13 00 00 41 83 e7 07 44 38 f8 0f 9e c2 84 c0 0f 95 c0 84 c2 0f 85 d7 13 00 00 4c 89 f2 <44> 0f b6 79 05 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04
RSP: 0018:ffffc90003fcf2b0 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff912c321e
RDX: ffffc90003fcf355 RSI: 0000000000000001 RDI: ffffffff90a437e4
RBP: ffffc90003fcf368 R08: ffffffff912c3222 R09: 000000008354c23c
R10: ffff88807a8e2ff0 R11: 0000000000012641 R12: ffffc90003fcf370
R13: ffffc90003fcf320 R14: ffffc90003fcf355 R15: 0000000000000003
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 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+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2543 [inline]
 slab_free mm/slub.c:6642 [inline]
 kfree+0x29e/0x710 mm/slub.c:6849
 tomoyo_realpath_from_path+0x19f/0x6e0 security/tomoyo/realpath.c:286
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_check_open_permission+0x2ab/0x3c0 security/tomoyo/file.c:771
 tomoyo_file_open+0x6b/0x90 security/tomoyo/tomoyo.c:334
 security_file_open+0x84/0x1e0 security/security.c:3183
 do_dentry_open+0x597/0x1590 fs/open.c:939
 vfs_open+0x82/0x3f0 fs/open.c:1094
 do_open fs/namei.c:4628 [inline]
 path_openat+0x2078/0x3140 fs/namei.c:4787
 do_filp_open+0x20b/0x470 fs/namei.c:4814
 do_sys_openat2+0x11f/0x280 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+0x174/0x210 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcc14ca7407
RSP: 002b:00007ffe8b4afd60 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fcc1536b880 RCX: 00007fcc14ca7407
RDX: 0000000000080141 RSI: 00005565120d702e RDI: ffffffffffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000000001a4 R11: 0000000000000202 R12: 00000000ffffffff
R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000
 </TASK>
task:kworker/u8:9    state:R  running task     stack:23432 pid:1157  tgid:1157  ppid:2      task_flags:0x4208060 flags:0x00080000
Workqueue: kvfree_rcu_reclaim kfree_rcu_work
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6855
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7182
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x66d/0x20a0 arch/x86/kernel/unwind_orc.c:581
Code: 0f 95 c6 40 84 f7 0f 85 58 15 00 00 83 e0 07 38 c2 40 0f 9e c6 84 d2 0f 95 c0 40 84 c6 0f 85 41 15 00 00 4c 0f bf 31 4d 01 fe <0f> b6 41 05 83 e0 07 3c 03 0f 84 0a 09 00 00 3c 04 0f 84 43 08 00
RSP: 0018:ffffc900044ef650 EFLAGS: 00000282
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff912b6588
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
RBP: ffffc900044ef708 R08: ffffffff912b658c R09: 0000000082adb3ed
R10: ffff88802849d4b0 R11: 0000000000011b82 R12: ffffc900044ef710
R13: ffffc900044ef6c0 R14: ffffc900044efb20 R15: ffffc900044efb10
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:56
 kasan_save_track+0x14/0x30 mm/kasan/common.c:77
 __kasan_save_free_info+0x3b/0x60 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+0x5f/0x80 mm/kasan/common.c:284
 kasan_slab_free include/linux/kasan.h:234 [inline]
 slab_free_hook mm/slub.c:2543 [inline]
 slab_free_freelist_hook mm/slub.c:2572 [inline]
 slab_free_bulk mm/slub.c:6674 [inline]
 kmem_cache_free_bulk mm/slub.c:7358 [inline]
 kmem_cache_free_bulk+0x2bf/0x680 mm/slub.c:7337
 kfree_bulk include/linux/slab.h:830 [inline]
 kvfree_rcu_bulk+0x1b7/0x1e0 mm/slab_common.c:1522
 kfree_rcu_work+0x124/0x1a0 mm/slab_common.c:1600
 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3427
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
task:syz.1.3853      state:R  running task     stack:27368 pid:21943 tgid:21939 ppid:18928  task_flags:0x400040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6855
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7182
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:avtab_node_cmp security/selinux/ss/avtab.c:103 [inline]
RIP: 0010:avtab_search_node+0x293/0x4b0 security/selinux/ss/avtab.c:189
Code: 03 42 80 3c 28 00 0f 85 ee 01 00 00 48 8b 5b 10 48 85 db 0f 84 14 01 00 00 e8 d9 5e 61 fd 48 89 d8 48 c1 e8 03 42 0f b6 14 28 <48> 89 d8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 ae 01 00 00 0f
RSP: 0018:ffffc9000c7bf840 EFLAGS: 00000a02
RAX: 1ffff110065d2273 RBX: ffff888032e91398 RCX: 1ffff1100adee326
RDX: 0000000000000000 RSI: ffffffff845c8157 RDI: ffffc9000c7bf976
RBP: ffffc9000c7bf970 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000800 R11: 000000000ac0d5af R12: 00000000000004bc
R13: dffffc0000000000 R14: 0000000000000486 R15: 0000000000000006
 context_struct_compute_av+0x622/0x1270 security/selinux/ss/services.c:664
 security_compute_av+0x5ec/0x11d0 security/selinux/ss/services.c:1177
 avc_compute_av+0x83/0x7f0 security/selinux/avc.c:991
 avc_has_extended_perms+0xcdf/0x1090 security/selinux/avc.c:1042
 ioctl_has_perm.constprop.0.isra.0+0x379/0x540 security/selinux/hooks.c:3841
 selinux_file_ioctl+0x180/0x270 security/selinux/hooks.c:3889
 security_file_ioctl+0xc6/0x240 security/security.c:2982
 __do_sys_ioctl fs/ioctl.c:591 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __x64_sys_ioctl+0xb7/0x210 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6e5a18f34b
RSP: 002b:00007f6e583cd050 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f6e5a3e6128 RCX: 00007f6e5a18f34b
RDX: 0000000000000000 RSI: 0000000000006364 RDI: 00000000000000d9
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffff16b2047
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000001
R13: 00007f6e5a3e6128 R14: 00007ffff16b1f60 R15: 00007ffff16b2048
 </TASK>
rcu: rcu_preempt kthread starved for 10597 jiffies! g114961 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:27960 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5248 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6855
 __schedule_loop kernel/sched/core.c:6937 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6952
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
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 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 76 76 02 e9 d3 2f 03 00 0f 1f 00 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 13 d3 2b 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c2
RAX: 0000000005d8ccb7 RBX: 0000000000000000 RCX: ffffffff8b5e86f9
RDX: 0000000000000000 RSI: ffffffff8daa3473 RDI: ffffffff8bf1d300
RBP: fffffbfff1c12f50 R08: 0000000000000001 R09: ffffed101708672d
R10: ffff8880b843396b R11: 00000000ffffffff R12: 0000000000000000
R13: ffffffff8e097a80 R14: ffffffff9085ced0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88812499c000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000516b3000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3f6/0x4d0 init/main.c:1111
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>