INFO: rcu detected stall in security_file_open

Status: upstream: reported syz repro on 2025/11/22 02:38
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+fa7645d1f6376ab08651@syzkaller.appspotmail.com
First crash: 274d, last: 123d
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2026/01/25 upstream (ToT) d91a46d6805a syz [report] INFO: rcu detected stall in corrupted
2026/07/04 upstream (ToT) 1e9cdc2ea15a syz Failed due to an error; will retry later
▶ ▼ Similar bugs (12)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in security_file_open (5) tomoyo 1 4 1732d 1842d 0/29 closed as invalid on 2022/02/08 09:50
upstream INFO: rcu detected stall in security_file_open (3) afs 1 syz, C done done 2 2153d 2152d 15/29 fixed on 2020/11/16 12:12
upstream INFO: rcu detected stall in security_file_open mm 1 5 2453d 2454d 0/29 closed as invalid on 2019/12/04 14:04
upstream INFO: rcu detected stall in security_file_open (2) mm 1 2 2419d 2419d 0/29 closed as invalid on 2020/01/08 05:23
linux-6.1 INFO: rcu detected stall in security_file_open 1 1 1068d 1068d 0/3 auto-obsoleted due to no activity on 2023/12/28 22:15
linux-6.1 INFO: rcu detected stall in security_file_open (3) 1 6 171d 362d 0/3 auto-obsoleted due to no activity on 2026/06/12 23:26
linux-5.15 INFO: rcu detected stall in security_file_open (2) origin:upstream 1 syz error 11 1d00h 557d 0/3 upstream: reported syz repro on 2025/02/11 10:29
upstream INFO: rcu detected stall in security_file_open (4) tomoyo 1 1 1951d 1951d 0/29 auto-closed as invalid on 2021/06/18 10:54
linux-6.1 INFO: rcu detected stall in security_file_open (2) 1 1 724d 724d 0/3 auto-obsoleted due to no activity on 2024/12/06 07:18
linux-5.15 INFO: rcu detected stall in security_file_open 1 3 677d 763d 0/3 auto-obsoleted due to no activity on 2025/01/22 08:07
upstream INFO: rcu detected stall in security_file_open (6) tomoyo mm 1 syz, C error 468 16h59m 1152d 0/29 closed as dup on 2023/06/27 10:07
linux-6.1 INFO: rcu detected stall in security_file_open (4) 1 syz, C 2 13d 28d 0/3 upstream: reported C repro on 2026/07/25 17:02

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 GPs behind) idle=dc9c/1/0x4000000000000000 softirq=12108/12109 fqs=1
rcu: 	(detected by 1, t=10502 jiffies, g=9241, q=99 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5139 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:127 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:178 [inline]
RIP: 0010:kasan_check_range+0x89/0x290 mm/kasan/generic.c:187
Code: 00 fc ff df 4d 8d 34 19 4d 89 f4 4d 29 dc 49 83 fc 10 7f 29 4d 85 e4 0f 84 41 01 00 00 4c 89 cb 48 f7 d3 4c 01 fb 41 80 3b 00 <0f> 85 cc 01 00 00 49 ff c3 48 ff c3 75 ee e9 21 01 00 00 44 89 dd
RSP: 0018:ffffc90000007888 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffffffffffff RCX: ffffffff816710b0
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff90d94500
RBP: ffffc90000007b08 R08: ffffffff90d94507 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a0 R12: 0000000000000001
R13: ffff88807cfc8000 R14: fffffbfff21b28a1 R15: 1ffffffff21b28a0
FS:  00007fd0e7d4e880(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000192cf000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 instrument_atomic_read include/linux/instrumented.h:68 [inline]
 _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
 hlock_class kernel/locking/lockdep.c:228 [inline]
 __lock_acquire+0x1260/0x7c80 kernel/locking/lockdep.c:5134
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
 rcu_read_lock include/linux/rcupdate.h:786 [inline]
 advance_sched+0xa15/0xc80 net/sched/sch_taprio.c:1001
 __run_hrtimer kernel/time/hrtimer.c:1750 [inline]
 __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1814
 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline]
 __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa9/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 0a d9 1a f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> e2 53 ea f6 65 8b 05 d3 9a 92 75 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90003317500 EFLAGS: 00000206
RAX: a32ad3e06ddf3600 RBX: 0000000000000a06 RCX: a32ad3e06ddf3600
RDX: dffffc0000000000 RSI: ffffffff8aaabce0 RDI: 0000000000000001
RBP: ffffc90003317580 R08: ffffffff90d9453f R09: 1ffffffff21b28a7
R10: dffffc0000000000 R11: fffffbfff21b28a8 R12: dffffc0000000000
R13: ffff88801d7dad00 R14: ffffffff971448c8 R15: 1ffff92000662ea0
 __debug_check_no_obj_freed lib/debugobjects.c:999 [inline]
 debug_check_no_obj_freed+0x51f/0x540 lib/debugobjects.c:1020
 slab_free_hook mm/slub.c:1786 [inline]
 slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 tomoyo_check_open_permission+0x2d3/0x3c0 security/tomoyo/file.c:786
 security_file_open+0x62/0xa0 security/security.c:2854
 do_dentry_open+0x380/0x1500 fs/open.c:916
 do_open fs/namei.c:3640 [inline]
 path_openat+0x274b/0x3190 fs/namei.c:3797
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421
 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+0x139/0x160 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd0e7e48c3a
Code: 41 89 f2 48 89 54 24 e0 41 83 e2 40 75 2a 89 f0 f7 d0 a9 00 00 41 00 74 1f 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 2e c3 0f 1f 44 00 00 48 8d 44 24 08 c7 44 24
RSP: 002b:00007ffefa531928 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055f94b117da0 RCX: 00007fd0e7e48c3a
RDX: 0000000000090800 RSI: 000055f94b0b6510 RDI: 00000000ffffff9c
RBP: 000055f94b0b6510 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 000055f94b0c27b0
R13: 00000000000000fd R14: 000055f93bc12be0 R15: 00007ffefa531c30
 </TASK>
rcu: rcu_preempt kthread starved for 10500 jiffies! g9241 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:27080 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5380 [inline]
 __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699
 schedule+0xbd/0x170 kernel/sched/core.c:6773
 schedule_timeout+0x160/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x99/0x380 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
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 2988 Comm: kworker/u4:9 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline]
RIP: 0010:smp_call_function_many_cond+0xddf/0x1130 kernel/smp.c:855
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 6a d7 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 a5 d3 0a 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 89 d3
RSP: 0018:ffffc9000bef7780 EFLAGS: 00000293
RAX: ffffffff817abd37 RBX: 1ffff110171c8759 RCX: ffff88802b960000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000bef7900 R08: ffffffff90d94507 R09: 1ffffffff21b28a0
R10: dffffc0000000000 R11: fffffbfff21b28a1 R12: ffff8880b8e43ac8
R13: dffffc0000000000 R14: ffff8880b8f3d148 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0e7d47000 CR3: 000000000cb30000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022
 on_each_cpu include/linux/smp.h:71 [inline]
 text_poke_sync arch/x86/kernel/alternative.c:2222 [inline]
 text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432
 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline]
 text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630
 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207
 static_key_enable+0x1a/0x20 kernel/jump_label.c:220
 toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831
 process_one_work kernel/workqueue.c:2634 [inline]
 process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
 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
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/09 04:29 linux-6.6.y 5fa4793a2d2d d6526ea3 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan INFO: rcu detected stall in security_file_open
2026/04/21 10:06 linux-6.6.y 9760bf04666d 3f2e655b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in security_file_open
2026/02/15 19:51 linux-6.6.y 1b4ef5214f17 1e62d198 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan-perf INFO: rcu detected stall in security_file_open
2025/12/01 06:50 linux-6.6.y 1e89a1be4fe9 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in security_file_open
2025/11/22 02:37 linux-6.6.y 0a805b6ea8cd 4fb8ef37 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan INFO: rcu detected stall in security_file_open
* Struck through repros no longer work on HEAD.