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VFS: Busy inodes after unmount (use-after-free) (2)

Status: upstream: reported C repro on 2025/05/11 08:46
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+1134d3a5b062e9665a7a@syzkaller.appspotmail.com
First crash: 9d21h, last: 44m
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] VFS: Busy inodes after unmount (use-after-free) (2) 0 (1) 2025/05/11 08:46
▶ ▼ Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-54 VFS: Busy inodes after unmount (use-after-free) C 4 755d 811d 0/2 auto-obsoleted due to no activity on 2023/08/20 15:35
linux-6.1 VFS: Busy inodes after unmount (use-after-free) origin:lts-only C inconclusive 1617 17d 790d 0/3 upstream: reported C repro on 2023/03/18 09:53
android-5-15 VFS: Busy inodes after unmount (use-after-free) origin:downstream C error done 2 709d 811d 0/2 auto-obsoleted due to no activity on 2023/09/15 20:27
android-5-10 VFS: Busy inodes after unmount (use-after-free) C done inconclusive 1 811d 811d 0/2 auto-obsoleted due to no activity on 2023/06/25 23:02
upstream VFS: Busy inodes after unmount (use-after-free) bcachefs C error 55684 11d 842d 28/28 fixed on 2025/05/06 15:33
linux-5.15 VFS: Busy inodes after unmount (use-after-free) missing-backport origin:upstream C unreliable 2324 1d18h 789d 0/3 upstream: reported C repro on 2023/03/19 11:46

Sample crash report:
BTRFS info (device loop0): last unmount of filesystem c9fe44da-de57-406a-8241-57ec7d4412cf
VFS: Busy inodes after unmount of loop0 (btrfs)
------------[ cut here ]------------
kernel BUG at fs/super.c:652!
Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 6484 Comm: syz-executor107 Not tainted 6.15.0-rc4-syzkaller-ge0f4c8dd9d2d #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : generic_shutdown_super+0x2b4/0x2b8 fs/super.c:650
lr : generic_shutdown_super+0x2b4/0x2b8 fs/super.c:650
sp : ffff8000a43f7ba0
x29: ffff8000a43f7ba0 x28: 00007dfe9b1ba808 x27: ffff80008f301de8
x26: ffffffffffffffff x25: dfff800000000000 x24: 1fffe00018b9bcf0
x23: ffff80008b2817e0 x22: dfff800000000000 x21: 0000000000000000
x20: ffff80008fa4d4c0 x19: ffff0000c5cde000 x18: 1fffe00036711a76
x17: ffff80008f2fe000 x16: ffff80008ada5d6c x15: 0000000000000001
x14: 1ffff0001487eee0 x13: 0000000000000000 x12: 0000000000000000
x11: ffff70001487eee1 x10: 0000000000ff0100 x9 : 9c3427ac6e3c7500
x8 : 9c3427ac6e3c7500 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a43f7538 x4 : ffff80008f3f4fa0 x3 : ffff800082faeee4
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 000000000000002f
Call trace:
 generic_shutdown_super+0x2b4/0x2b8 fs/super.c:650 (P)
 kill_anon_super+0x4c/0x7c fs/super.c:1237
 btrfs_kill_super+0x40/0x58 fs/btrfs/super.c:2099
 deactivate_locked_super+0xc4/0x12c fs/super.c:473
 deactivate_super+0xe0/0x100 fs/super.c:506
 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1435
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1442
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 do_notify_resume+0x16c/0x1ec arch/arm64/kernel/entry-common.c:151
 exit_to_user_mode_prepare arch/arm64/kernel/entry-common.c:169 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:178 [inline]
 el0_svc+0xb0/0x150 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Code: b0051160 91350000 9119a261 97cfbb64 (d4210000) 
---[ end trace 0000000000000000 ]---

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/07 10:25 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e0f4c8dd9d2d 350f4ffc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/07 10:06 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e0f4c8dd9d2d 350f4ffc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/07 09:32 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e0f4c8dd9d2d 350f4ffc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/15 07:23 upstream c94d59a126cb d6b2ee52 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs VFS: Busy inodes after unmount (use-after-free)
2025/05/13 20:15 upstream e9565e23cd89 7344edeb .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs VFS: Busy inodes after unmount (use-after-free)
2025/05/11 02:35 upstream bec6f00f120e 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs VFS: Busy inodes after unmount (use-after-free)
2025/05/17 05:38 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci a82e92598ab1 f41472b0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/13 21:27 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c32f8dc5aaf9 7344edeb .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/12 23:17 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c32f8dc5aaf9 f6671af7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/12 10:16 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci c32f8dc5aaf9 77908e5f .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/07 08:36 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e0f4c8dd9d2d 350f4ffc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
2025/05/07 08:36 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci e0f4c8dd9d2d 350f4ffc .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 VFS: Busy inodes after unmount (use-after-free)
* Struck through repros no longer work on HEAD.