INFO: rcu detected stall in kernfs_fop_release

Status: auto-obsoleted due to no activity on 2025/12/04 02:18
Subsystems: kernfs
[Documentation on labels]
Reported-by: syzbot+74de79467b28a6242ae0@syzkaller.appspotmail.com
First crash: 1410d, last: 350d
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] INFO: rcu detected stall in kernfs_fop_release 1 (2) 2022/10/01 14:25
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: rcu detected stall in kernfs_fop_release 1 2 709d 714d 0/3 auto-obsoleted due to no activity on 2024/12/10 13:10
upstream INFO: rcu detected stall in kernfs_fop_release (2) bpf kernfs 1 3 230d 241d 0/29 auto-obsoleted due to no activity on 2026/03/24 14:55
android-5-15 BUG: soft lockup in kernfs_fop_release 1 2 840d 846d 0/2 auto-obsoleted due to no activity on 2024/07/22 00:19
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/09/09 02:41 43m retest repro linux-next no crash log
2025/06/26 02:07 41m retest repro linux-next report log
2025/04/17 01:37 24m retest repro linux-next error
2025/02/05 22:14 32m retest repro linux-next report log
2024/11/27 06:08 26m retest repro linux-next report log
2024/11/05 05:34 16m retest repro https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing no crash log
2024/09/18 02:12 17m retest repro linux-next report log
2024/07/10 00:45 18m retest repro linux-next report log
2024/04/27 04:03 18m retest repro linux-next report log
2024/01/28 04:24 21m retest repro linux-next report log

Sample crash report:
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
 P7040/1:b..l

rcu: 	(detected by 0, t=10502 jiffies, g=54425, q=452 ncpus=2)
task:udevd           state:R
  running task     stack:22952 pid:7040  tgid:7040  ppid:5217   task_flags:0x400140 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6786
 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109
 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x1721/0x2390 arch/x86/kernel/unwind_orc.c:648
Code: 18 02 00 00 80 3d be cf 33 11 00 0f 85 0b 02 00 00 c6 05 b1 cf 33 11 01 4c 89 f7 e8 89 0c 00 00 e9 f7 01 00 00 48 8b 54 24 08 <48> 8d 5a 02 48 83 c2 03 48 89 d8 48 c1 e8 03 0f b6 04 28 84 c0 0f
RSP: 0018:ffffc9000b747818 EFLAGS: 00000246

RAX: 0000000000000000 RBX: ffffc9000b747980 RCX: 0000000000000000
RDX: ffffffff903188ba RSI: 0000000000000001 RDI: ffffc9000b7479a8
RBP: dffffc0000000000 R08: ffffc9000b7479a7 R09: 0000000000000000
R10: ffffc9000b747998 R11: fffff520016e8f35 R12: ffffc9000b747948
R13: ffffc9000b747998 R14: ffffc9000b747948 R15: 1ffffffff2063117
 __unwind_start+0x5b9/0x760 arch/x86/kernel/unwind_orc.c:758
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0xe4/0x150 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kfree+0x18e/0x440 mm/slub.c:4842
 kernfs_fop_release+0x160/0x190 fs/kernfs/file.c:768
 __fput+0x449/0xa70 fs/file_table.c:465
 fput_close_sync+0x119/0x200 fs/file_table.c:570
 __do_sys_close fs/open.c:1589 [inline]
 __se_sys_close fs/open.c:1574 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1574
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f5e8a7407
RSP: 002b:00007ffee6809100 EFLAGS: 00000202
 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00007f7f5ef50880 RCX: 00007f7f5e8a7407
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000008
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000559a01711940
R13: 0000000000000005 R14: 00007ffee68095e0 R15: 00005599c8c24bcc
 </TASK>
rcu: rcu_preempt kthread starved for 3403 jiffies! g54425 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:27128 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x16f5/0x4d00 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6879
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
 kthread+0x70e/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:variable_ffs arch/x86/include/asm/bitops.h:318 [inline]
RIP: 0010:handle_softirqs+0x1b0/0x870 kernel/softirq.c:567
Code: 89 64 24 30 0f b7 db 48 c7 c7 00 ad 89 8b e8 a7 ae e9 09 65 66 c7 05 85 9b 1a 11 00 00 e8 d8 0a 42 00 fb 49 c7 c7 c0 c0 e0 8d <b8> ff ff ff ff 0f bc c3 41 89 c5 41 ff c5 0f 84 c2 03 00 00 89 5c
RSP: 0018:ffffc90000007e40 EFLAGS: 00000286

RAX: 61aedf5dbe714000 RBX: 0000000000000100 RCX: 61aedf5dbe714000
RDX: 0000000000000000 RSI: ffffffff8d998d6f RDI: ffffffff8be29d80
RBP: ffffc90000007f50 R08: ffffffff8fa1f5f7 R09: 1ffffffff1f43ebe
R10: dffffc0000000000 R11: fffffbfff1f43ebf R12: 000000000000000a
R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff8de0c0c0
FS:  0000000000000000(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5f60117d58 CR3: 0000000077800000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: d3 de 02 00 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 d3 ed 18 00 f3 0f 1e fa fb f4 <c3> cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c2

RAX: 61aedf5dbe714000 RBX: ffffffff81976a48 RCX: 61aedf5dbe714000
RDX: 0000000000000001 RSI: ffffffff8d998d6f RDI: ffffffff8be29d80
RBP: ffffffff8de07ea8 R08: ffff8880b8632f5b R09: 1ffff110170c65eb
R10: dffffc0000000000 R11: ffffed10170c65ec R12: ffffffff8fa1f5f0
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a50
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:749
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:745
 start_kernel+0x47d/0x500 init/main.c:1102
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:307
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:288
 common_startup_64+0x13e/0x147
 </TASK>
vkms_vblank_simulate: vblank timer overrun

Crashes (8):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/16 00:45 upstream 155a3c003e55 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in kernfs_fop_release
2025/06/06 20:37 upstream e271ed52b344 f61267d4 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce INFO: rcu detected stall in kernfs_fop_release
2024/06/11 09:31 upstream 83a7eefedc9b 048c640a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root INFO: rcu detected stall in kernfs_fop_release
2024/04/12 03:49 upstream fe46a7dd189e 478efa7f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root INFO: rcu detected stall in kernfs_fop_release
2025/08/26 02:17 linux-next 7fa4d8dc380f bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in kernfs_fop_release
2024/10/21 18:33 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing c6d9e43954bf f1e4447c .config console log report syz / log [disk image] [vmlinux] [kernel image] ci2-upstream-usb INFO: rcu detected stall in kernfs_fop_release
2023/10/02 02:58 https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing 6465e260f487 8e26a358 .config console log report info ci2-upstream-usb INFO: rcu detected stall in kernfs_fop_release
2022/10/01 08:11 linux-next aaa11ce2ffc8 feb56351 .config console log report syz C [disk image] [vmlinux] ci-upstream-linux-next-kasan-gce-root INFO: rcu detected stall in kernfs_fop_release
* Struck through repros no longer work on HEAD.