WARNING in kernfs_remove_by_name_ns

Status: upstream: reported C repro on 2023/03/18 18:13
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+31f8f06b90e752e51bf8@syzkaller.appspotmail.com
First crash: 1313d, last: 1d11h
Fix bisection: failed (error log, bisect log)
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2023/05/19 upstream (ToT) 2d1bcbc6cd70 C [report] WARNING in kernfs_remove_by_name_ns
2026/10/09 upstream (ToT) af32da41b032 C Failed due to an error; will retry later
▶ ▼ Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in kernfs_remove_by_name_ns -1 syz, C error 6 392d 1168d 0/3 auto-obsoleted due to no activity on 2026/01/02 20:40
upstream WARNING in kernfs_remove_by_name_ns (2) kernfs -1 1 1984d 1980d 0/29 auto-closed as invalid on 2021/09/14 07:04
upstream WARNING in kernfs_remove_by_name_ns (3) kernfs -1 syz, C error 721 9h58m 1809d 0/29 upstream: reported C repro on 2021/11/08 11:24
upstream WARNING in kernfs_remove_by_name_ns kernfs -1 4 2603d 2678d 0/29 auto-closed as invalid on 2020/01/04 08:56
linux-5.15 WARNING in kernfs_remove_by_name_ns (2) -1 1 12d 12d 0/3 upstream: reported on 2026/10/10 09:02
▶ ▼ Fix bisection attempts (16)
Created Duration User Patch Repo Result
2025/02/27 09:09 13m bisect fix linux-6.1.y error job log
2025/01/26 12:36 2h05m bisect fix linux-6.1.y OK (0) job log log
2024/12/15 02:30 2h47m bisect fix linux-6.1.y OK (0) job log log
2024/10/31 02:29 3h01m bisect fix linux-6.1.y OK (0) job log log
2024/09/30 09:31 2h07m bisect fix linux-6.1.y OK (0) job log log
2024/08/21 12:35 2h08m bisect fix linux-6.1.y OK (0) job log log
2024/07/10 17:30 1h57m bisect fix linux-6.1.y OK (0) job log log
2024/06/01 11:47 2h07m bisect fix linux-6.1.y OK (0) job log log
2024/04/29 00:37 2h20m bisect fix linux-6.1.y OK (0) job log log
2024/03/28 22:57 2h40m bisect fix linux-6.1.y OK (0) job log log
2024/02/27 18:31 2h38m bisect fix linux-6.1.y OK (0) job log log
2024/01/18 19:09 2h42m bisect fix linux-6.1.y OK (0) job log log
2023/12/18 16:48 2h20m bisect fix linux-6.1.y OK (0) job log log
2023/10/17 19:43 1h15m bisect fix linux-6.1.y OK (0) job log log
2023/06/26 18:51 1h10m bisect fix linux-6.1.y OK (0) job log log
2023/05/25 14:14 57m bisect fix linux-6.1.y OK (0) job log log

Sample crash report:
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
kobject_add_internal failed for qgroups (error: -12 parent: 395ef67a-297e-477c-816d-cd80a5b93e5d)
------------[ cut here ]------------
kernfs: can not remove 'enabled', no directory
WARNING: CPU: 0 PID: 4600 at fs/kernfs/dir.c:1657 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
Modules linked in:
CPU: 0 PID: 4600 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
lr : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
sp : ffff8000221a7880
x29: ffff8000221a7880 x28: 1fffe000194ba1fd x27: 1fffe000194ba342
x26: dfff800000000000 x25: ffff800016b3f868 x24: 1ffff00002427a74
x23: dfff800000000000 x22: ffff800016b3f8a0 x21: 0000000000000000
x20: 0000000000000000 x19: ffff80001213d400 x18: 1fffe00033c1877e
x17: 0000000000000000 x16: ffff800011bcb318 x15: 0000000000000000
x14: 0000000000000001 x13: 1fffe00033c187a3 x12: 0000000000000000
x11: ff00800008195f68 x10: 0000000000000000 x9 : a1bc6c63f9984900
x8 : a1bc6c63f9984900 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000221a7318 x4 : ffff800016504f40 x3 : ffff800008542ee8
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000000
Call trace:
 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
 kernfs_remove_by_name include/linux/kernfs.h:622 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0xf4/0x278 fs/sysfs/group.c:288
 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:312
 __kobject_del+0x94/0x2d4 lib/kobject.c:587
 kobject_del+0x4c/0x6c lib/kobject.c:619
 btrfs_sysfs_del_qgroups+0x164/0x1b4 fs/btrfs/sysfs.c:2229
 btrfs_sysfs_add_qgroups+0x2a0/0x2ec fs/btrfs/sysfs.c:2268
 btrfs_quota_enable+0x1f8/0x1a74 fs/btrfs/qgroup.c:994
 btrfs_ioctl_quota_ctl+0x13c/0x180 fs/btrfs/ioctl.c:4626
 btrfs_ioctl+0x8f4/0xb38 fs/btrfs/ioctl.c:5613
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 77170
hardirqs last  enabled at (77169): [<ffff8000083154d0>] __up_console_sem+0xb4/0xfc kernel/printk/printk.c:261
hardirqs last disabled at (77170): [<ffff800011bc7440>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (77134): [<ffff8000081ae3b4>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (77134): [<ffff8000081ae3b4>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (77097): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
kernfs: can not remove 'inconsistent', no directory
WARNING: CPU: 0 PID: 4600 at fs/kernfs/dir.c:1657 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
Modules linked in:
CPU: 0 PID: 4600 Comm: syz.0.17 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
lr : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
sp : ffff8000221a7880
x29: ffff8000221a7880 x28: 1fffe000194ba1fd x27: 1fffe000194ba342
x26: dfff800000000000 x25: ffff800016b3f870 x24: 1ffff00002427a74
x23: dfff800000000000 x22: ffff800016b3f900 x21: 0000000000000000
x20: 0000000000000000 x19: ffff80001213d420 x18: 1fffe00033c1877e
x17: ffff80001641d000 x16: ffff8000082dd38c x15: ffff00019e0c3bfc
x14: 0000000000000001 x13: 1fffe0001aaef310 x12: 0000000000000000
x11: 0000000000000000 x10: ffff60001aaef311 x9 : a1bc6c63f9984900
x8 : a1bc6c63f9984900 x7 : ffff80000825ab2c x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : ffff8000082497f8
x2 : 0000000000000001 x1 : 0000000000000004 x0 : 0000000000000001
Call trace:
 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
 kernfs_remove_by_name include/linux/kernfs.h:622 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0xf4/0x278 fs/sysfs/group.c:288
 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:312
 __kobject_del+0x94/0x2d4 lib/kobject.c:587
 kobject_del+0x4c/0x6c lib/kobject.c:619
 btrfs_sysfs_del_qgroups+0x164/0x1b4 fs/btrfs/sysfs.c:2229
 btrfs_sysfs_add_qgroups+0x2a0/0x2ec fs/btrfs/sysfs.c:2268
 btrfs_quota_enable+0x1f8/0x1a74 fs/btrfs/qgroup.c:994
 btrfs_ioctl_quota_ctl+0x13c/0x180 fs/btrfs/ioctl.c:4626
 btrfs_ioctl+0x8f4/0xb38 fs/btrfs/ioctl.c:5613
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 77254
hardirqs last  enabled at (77253): [<ffff80000825abc0>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline]
hardirqs last  enabled at (77253): [<ffff80000825abc0>] finish_lock_switch+0xb0/0x1c8 kernel/sched/core.c:5005
hardirqs last disabled at (77254): [<ffff800011bc7440>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (77236): [<ffff8000081ae3b4>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (77236): [<ffff8000081ae3b4>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (77207): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---
------------[ cut here ]------------
kernfs: can not remove 'drop_subtree_threshold', no directory
WARNING: CPU: 0 PID: 4600 at fs/kernfs/dir.c:1657 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
Modules linked in:
CPU: 0 PID: 4600 Comm: syz.0.17 Tainted: G        W          syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/23/2026
pstate: 62400005 (nZCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
lr : kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
sp : ffff8000221a7880
x29: ffff8000221a7880 x28: 1fffe000194ba1fd x27: 1fffe000194ba342
x26: dfff800000000000 x25: ffff800016b3f878 x24: 1ffff00002427a74
x23: dfff800000000000 x22: ffff800016b3f960 x21: 0000000000000000
x20: 0000000000000000 x19: ffff80001213d440 x18: 1fffe00033c1877e
x17: ffff80001641d000 x16: ffff8000082dd38c x15: ffff00019e0c3bfc
x14: 0000000000000001 x13: 1fffe0001aaef310 x12: 0000000000000000
x11: 0000000000000000 x10: ffff60001aaef311 x9 : a1bc6c63f9984900
x8 : a1bc6c63f9984900 x7 : ffff80000825ab2c x6 : 0000000000000000
x5 : 0000000000000080 x4 : 0000000000000001 x3 : ffff8000082497f8
x2 : 0000000000000001 x1 : 0000000000000004 x0 : 0000000000000001
Call trace:
 kernfs_remove_by_name_ns+0x108/0x184 fs/kernfs/dir.c:1656
 kernfs_remove_by_name include/linux/kernfs.h:622 [inline]
 remove_files fs/sysfs/group.c:28 [inline]
 sysfs_remove_group+0xf4/0x278 fs/sysfs/group.c:288
 sysfs_remove_groups+0x5c/0xb4 fs/sysfs/group.c:312
 __kobject_del+0x94/0x2d4 lib/kobject.c:587
 kobject_del+0x4c/0x6c lib/kobject.c:619
 btrfs_sysfs_del_qgroups+0x164/0x1b4 fs/btrfs/sysfs.c:2229
 btrfs_sysfs_add_qgroups+0x2a0/0x2ec fs/btrfs/sysfs.c:2268
 btrfs_quota_enable+0x1f8/0x1a74 fs/btrfs/qgroup.c:994
 btrfs_ioctl_quota_ctl+0x13c/0x180 fs/btrfs/ioctl.c:4626
 btrfs_ioctl+0x8f4/0xb38 fs/btrfs/ioctl.c:5613
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:856
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x12c arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 77536
hardirqs last  enabled at (77535): [<ffff80000825abc0>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1374 [inline]
hardirqs last  enabled at (77535): [<ffff80000825abc0>] finish_lock_switch+0xb0/0x1c8 kernel/sched/core.c:5005
hardirqs last disabled at (77536): [<ffff800011bc7440>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last  enabled at (77504): [<ffff8000081ae3b4>] softirq_handle_end kernel/softirq.c:439 [inline]
softirqs last  enabled at (77504): [<ffff8000081ae3b4>] handle_softirqs+0xb1c/0xc90 kernel/softirq.c:624
softirqs last disabled at (77257): [<ffff800008020e6c>] __do_softirq+0x14/0x20 kernel/softirq.c:630
---[ end trace 0000000000000000 ]---

Crashes (21):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/21 01:56 linux-6.1.y 79807e970724 df8746fb .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/11/18 12:52 linux-6.1.y fb2635ac69ab cb976f63 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/10/27 05:42 linux-6.1.y 32c9cdbe383c bf285f0c .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/03/18 18:30 linux-6.1.y 7eaef76fbc46 7939252e .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/07/15 13:43 linux-6.1.y 61fd484b2cf6 35d9ecc5 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2026/10/21 01:24 linux-6.1.y 79807e970724 df8746fb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2025/05/12 11:07 linux-6.1.y 02b72ccb5f9d 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2025/05/12 10:59 linux-6.1.y 02b72ccb5f9d 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2025/05/12 10:53 linux-6.1.y 02b72ccb5f9d 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2025/02/28 13:26 linux-6.1.y 3a8358583626 6a8fcbc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/11/06 01:06 linux-6.1.y 4a61839152cc 500bfdc4 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/10/27 05:25 linux-6.1.y 32c9cdbe383c bf285f0c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/09/14 06:03 linux-6.1.y 09045dae0d90 0b6a67ac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/09/05 18:45 linux-6.1.y c2cbfe5f5122 0b6286dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/08/27 10:36 linux-6.1.y cd363bb9548e 7ba13a15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/08/07 06:13 linux-6.1.y 52a953d0934b 4ffcc9ef .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/07/15 13:21 linux-6.1.y 61fd484b2cf6 35d9ecc5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/04/23 02:56 linux-6.1.y f17b0ab65d17 2b32bd34 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/04/15 10:53 linux-6.1.y 0102425ac76b ec410564 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/04/07 19:33 linux-6.1.y 543aff194ab6 f7ba566d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
2023/03/18 18:13 linux-6.1.y 7eaef76fbc46 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 WARNING in kernfs_remove_by_name_ns
* Struck through repros no longer work on HEAD.