syzbot


BUG: Dentry still in use in unmount (2)

Status: moderation: reported on 2024/12/16 01:50
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+844d026117149e737331@syzkaller.appspotmail.com
First crash: 9d11h, last: 9d11h
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: Dentry still in use in unmount f2fs C done 58 371d 848d 25/28 fixed on 2024/01/20 21:18
android-5-10 BUG: Dentry still in use [unmount of ext4 loop0] C error 63 1116d 1154d 0/2 closed as dup on 2021/10/28 13:08
android-5-10 BUG: Dentry still in use in unmount C done 1184 1032d 1044d 2/2 fixed on 2022/02/25 03:20
android-54 BUG: Dentry still in use [unmount of ramfs ramfs] C 476 1051d 1373d 0/2 auto-obsoleted due to no activity on 2023/04/21 02:49

Sample crash report:
------------[ cut here ]------------
BUG: Dentry ffff88806393ed38{i=16dd,n=binfmt_misc}  still in use (1) [unmount of proc proc]
WARNING: CPU: 0 PID: 8503 at fs/dcache.c:1546 umount_check fs/dcache.c:1546 [inline]
WARNING: CPU: 0 PID: 8503 at fs/dcache.c:1546 umount_check+0x188/0x200 fs/dcache.c:1536
Modules linked in:
CPU: 0 UID: 0 PID: 8503 Comm: syz.1.849 Not tainted 6.13.0-rc2-syzkaller-00031-gf92f4749861b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:umount_check fs/dcache.c:1546 [inline]
RIP: 0010:umount_check+0x188/0x200 fs/dcache.c:1536
Code: 00 00 00 4c 8b 75 40 e8 76 82 85 ff 4d 89 f9 45 89 e0 48 89 d9 41 55 4c 89 f2 48 89 de 48 c7 c7 40 43 5e 8b e8 99 59 46 ff 90 <0f> 0b 90 90 58 e9 b5 fe ff ff e8 49 82 85 ff 44 89 e6 bf 01 00 00
RSP: 0018:ffffc9000cc17c80 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88806393ed38 RCX: ffffffff815a16c9
RDX: ffff88802de7da00 RSI: ffffffff815a16d6 RDI: 0000000000000001
RBP: ffff88804e5b3018 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000001
R13: ffff888012260668 R14: 00000000000016dd R15: ffffffff8b60e820
FS:  0000555563f80500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1bf49e5b78 CR3: 0000000035360000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 d_walk+0x1e9/0xa20 fs/dcache.c:1277
 do_one_tree fs/dcache.c:1561 [inline]
 shrink_dcache_for_umount+0xb7/0x3e0 fs/dcache.c:1577
 generic_shutdown_super+0x76/0x3d0 fs/super.c:620
 kill_anon_super+0x3a/0x60 fs/super.c:1237
 proc_kill_sb+0x99/0x110 fs/proc/root.c:272
 deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
 deactivate_super+0xde/0x100 fs/super.c:506
 cleanup_mnt+0x222/0x450 fs/namespace.c:1373
 task_work_run+0x14e/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
 do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff90cb85d19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe5b063d18 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007ff90cd77ba0 RCX: 00007ff90cb85d19
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff90cd77ba0 R08: 000000000000021c R09: 00007ffe5b06400f
R10: 00007ff90cd77ac0 R11: 0000000000000246 R12: 000000000002e299
R13: 00007ff90cd76160 R14: 0000000000000032 R15: ffffffffffffffff
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/12 01:48 upstream f92f4749861b 6f1b0fa8 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto BUG: Dentry still in use in unmount
* Struck through repros no longer work on HEAD.