INFO: rcu detected stall in fsnotify_mark_destroy_workfn

Status: upstream: reported C repro on 2025/09/15 16:21
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+7af548db30457c83fc77@syzkaller.appspotmail.com
First crash: 315d, last: 281d
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: INFO: rcu detected stall in shmem_file_read_iter (log)
Repro: C syz .config
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/09/15 linux-6.1.y (ToT) 3db754f56897 C [report] INFO: rcu detected stall in corrupted
2025/09/15 upstream (ToT) f83ec76bf285 C Didn't crash
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in fsnotify_mark_destroy_workfn mm 1 14 2428d 2429d 0/29 closed as invalid on 2019/12/04 14:14
upstream INFO: rcu detected stall in fsnotify_mark_destroy_workfn (2) kernel 1 1 1287d 1287d 0/29 auto-obsoleted due to no activity on 2023/04/25 22:32
▶ ▼ Fix bisection attempts (8)
Created Duration User Patch Repo Result
2026/06/07 06:54 12m fix candidate upstream error job log
2026/04/26 11:26 17m fix candidate upstream error job log
2026/03/27 02:43 5m fix candidate upstream error job log
2026/02/24 20:53 1m fix candidate upstream error job log
2026/01/24 13:43 1m fix candidate upstream error job log
2025/12/04 21:39 12h04m fix candidate upstream error job log
2025/10/31 19:36 11h49m fix candidate upstream error job log
2025/10/20 04:05 2h23m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
rcu: INFO: rcu_preempt detected expedited stalls on CPUs/tasks: { 1-.... } 2641 jiffies s: 4525 root: 0x2/.
rcu: blocking rcu_node structures (internal RCU debug):
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 46 Comm: kworker/u4:3 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound fsnotify_mark_destroy_workfn
RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:27 [inline]
RIP: 0010:static_key_false include/linux/jump_label.h:207 [inline]
RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:147 [inline]
RIP: 0010:wrmsr arch/x86/include/asm/msr.h:254 [inline]
RIP: 0010:native_apic_msr_write+0x35/0x50 arch/x86/include/asm/apic.h:206
Code: 74 2a 83 ff 30 74 25 eb 10 81 ff d0 00 00 00 74 1b 81 ff e0 00 00 00 74 13 c1 ef 04 81 c7 00 08 00 00 89 f9 89 f0 31 d2 0f 30 <66> 90 c3 89 f6 31 d2 e9 ef c7 f7 02 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0018:ffffc900001e0508 EFLAGS: 00000046
RAX: 00000000000000f6 RBX: ffffffff8c5e4b88 RCX: 000000000000083f
RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f
RBP: 0000000000000001 R08: dffffc0000000000 R09: fffff5200003c091
R10: fffff5200003c091 R11: 1ffff9200003c090 R12: 0000000000000000
R13: dffffc0000000001 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000cf3d CR3: 000000005997c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_irq_work_raise+0x82/0xd0 arch/x86/kernel/irq_work.c:31
 irq_work_queue_on+0x13c/0x260 kernel/irq_work.c:165
 rcu_read_unlock_special+0x3c7/0x500 kernel/rcu/tree_plugin.h:678
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 trace_call_bpf+0x58c/0x680 kernel/trace/bpf_trace.c:137
 perf_trace_run_bpf_submit+0x79/0x1c0 kernel/events/core.c:9997
 perf_trace_preemptirq_template+0x287/0x330 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0xd3/0x140 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x24/0x40 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:728
RIP: 0010:rcu_read_unlock_special+0x84/0x500 kernel/rcu/tree_plugin.h:685
Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 2d 97 96 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 40 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b
RSP: 0018:ffffc900001e09c0 EFLAGS: 00000206
RAX: 8af1a92473be1e00 RBX: 1ffff9200003c140 RCX: 8af1a92473be1e00
RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: ffffffff8adefca0
RBP: ffffc900001e0ac0 R08: dffffc0000000000 R09: fffffbfff215c460
R10: fffffbfff215c460 R11: 1ffffffff215c45f R12: 0000000000000246
R13: dffffc0000000000 R14: ffff8880b8f3b900 R15: 0000000000000002
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:426
 rcu_read_unlock include/linux/rcupdate.h:823 [inline]
 process_backlog+0x3ff/0x6e0 net/core/dev.c:6024
 __napi_poll+0xc0/0x460 net/core/dev.c:6590
 napi_poll net/core/dev.c:6657 [inline]
 net_rx_action+0x5b1/0xad0 net/core/dev.c:6771
 handle_softirqs+0x2a1/0x920 kernel/softirq.c:596
 __do_softirq kernel/softirq.c:630 [inline]
 invoke_softirq kernel/softirq.c:470 [inline]
 __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:679
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:691
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1118 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1118
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:get_lock_parent_ip include/linux/ftrace.h:950 [inline]
RIP: 0010:preempt_latency_start kernel/sched/core.c:5691 [inline]
RIP: 0010:preempt_count_add+0x8d/0x190 kernel/sched/core.c:5716
Code: ba aa 7e 0f b6 c0 3d f5 00 00 00 73 58 65 8b 05 21 ba aa 7e 25 ff ff ff 7f 39 f8 75 42 48 8b 5c 24 18 48 89 df e8 43 6d 0c 00 <85> c0 74 09 31 db 31 ff e8 36 6d 0c 00 65 4c 8b 35 ee b9 aa 7e 49
RSP: 0018:ffffc90000b77630 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8138651f RCX: ffffffff96be9100
RDX: dffffc0000000000 RSI: ffffffff81d0cc26 RDI: ffffffff8138651f
RBP: ffffc90000b77770 R08: ffffc90000b777f0 R09: 0000000000000002
R10: fffff5200016eef1 R11: 1ffff9200016eeef R12: ffffffff81d0cc26
R13: ffffc90000b77ab0 R14: dffffc0000000000 R15: dffffc0000000000
 unwind_next_frame+0xaf/0x20b0 arch/x86/kernel/unwind_orc.c:433
 arch_stack_walk+0x10c/0x140 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x98/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2d/0x50 mm/kasan/generic.c:516
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:177 [inline]
 slab_free_hook mm/slub.c:1729 [inline]
 slab_free_freelist_hook+0x131/0x1a0 mm/slub.c:1755
 slab_free mm/slub.c:3687 [inline]
 kmem_cache_free+0xf7/0x290 mm/slub.c:3709
 fsnotify_final_mark_destroy fs/notify/mark.c:304 [inline]
 fsnotify_mark_destroy_workfn+0x24f/0x2e0 fs/notify/mark.c:928
 process_one_work+0x898/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1250 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/15 16:21 linux-6.1.y 3db754f56897 e2beed91 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-perf INFO: rcu detected stall in fsnotify_mark_destroy_workfn
* Struck through repros no longer work on HEAD.