syzbot


BUG: Dentry still in use [unmount of devpts devpts]

Status: upstream: reported C repro on 2020/12/21 14:18
Reported-by: syzbot+389aac15e12819c19cc4@syzkaller.appspotmail.com
First crash: 715d, last: 419d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-5-10 BUG: Dentry still in use [unmount of ext4 loop0] C error 63 370d 409d 0/2 closed as dup on 2021/10/28 13:08
android-5-10 BUG: Dentry still in use [unmount of devpts devpts] 1 408d 408d 0/2 closed as dup on 2021/10/28 13:08

Sample crash report:
incfs: Can't find or create .index dir in ./file0
BUG: Dentry 00000000bb33c990{i=0,n=.index}  still in use (1) [unmount of devpts devpts]
------------[ cut here ]------------
WARNING: CPU: 0 PID: 360 at fs/dcache.c:1597 umount_check+0x179/0x1c0 fs/dcache.c:1588
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 360 Comm: syz-executor188 Not tainted 5.4.85-syzkaller-00188-g8657d5d6282f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1dd/0x24e lib/dump_stack.c:118
 panic+0x285/0x750 kernel/panic.c:221
 __warn+0x1fd/0x200 kernel/panic.c:582
 report_bug+0x390/0x4d0 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 do_error_trap arch/x86/kernel/traps.c:272 [inline]
 do_invalid_op+0x6e/0x110 arch/x86/kernel/traps.c:291
 invalid_op+0x1e/0x30 arch/x86/entry/entry_64.S:1029
RIP: 0010:umount_check+0x179/0x1c0 fs/dcache.c:1588
Code: ff 4c 8b 0b 48 81 c5 20 04 00 00 48 c7 c7 63 3e 1d 85 4c 89 fe 4c 89 f2 4c 89 f9 45 89 e8 31 c0 55 e8 27 54 b0 ff 48 83 c4 08 <0f> 0b e9 fd fe ff ff 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c d4 fe ff
RSP: 0018:ffff8881ec5ffa48 EFLAGS: 00010286
RAX: 0000000000000057 RBX: ffffffff8547f6b8 RCX: 4e31a831340f5c00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: ffff8881e8ac5420 R08: ffffffff814e3421 R09: ffffed103ee05e08
R10: ffffed103ee05e08 R11: 0000000000000000 R12: dffffc0000000000
R13: 0000000000000001 R14: 0000000000000000 R15: ffff8881eff3cbb0
 d_walk+0x2e9/0x570 fs/dcache.c:1307
 do_one_tree fs/dcache.c:1604 [inline]
 shrink_dcache_for_umount+0x8a/0x1b0 fs/dcache.c:1620
 generic_shutdown_super+0x63/0x2a0 fs/super.c:447
 kill_anon_super fs/super.c:1108 [inline]
 kill_litter_super+0x71/0xa0 fs/super.c:1117
 deactivate_locked_super+0xaf/0x100 fs/super.c:335
 deactivate_super+0x1b8/0x280 fs/super.c:366
 cleanup_mnt+0x432/0x4e0 fs/namespace.c:1102
 task_work_run+0x176/0x1a0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xcc2/0x2830 kernel/exit.c:811
 do_group_exit+0x155/0x2b0 kernel/exit.c:909
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:920
 __se_sys_exit_group+0x10/0x10 kernel/exit.c:918
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:918
 do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x443958
Code: Bad RIP value.
RSP: 002b:00007ffc24b11118 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000443958
RDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001
RBP: 00000000004c39d0 R08: 00000000000000e7 R09: ffffffffffffffd4
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d6180 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (11):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-android-5-4-kasan 2020/12/22 21:02 android12-5.4 8657d5d6282f 04201c06 .config log report syz C
ci2-android-5-4-kasan 2021/10/13 21:34 android12-5.4 2ffb0acdabc5 5462d470 .config log report info BUG: Dentry still in use [unmount of devpts devpts]
ci2-android-5-4-kasan 2021/10/02 01:43 android12-5.4 1e429b8f9eb9 cc80db95 .config log report info BUG: Dentry still in use [unmount of devpts devpts]
ci2-android-5-4-kasan 2021/06/10 06:48 android12-5.4 e5f6b8e5e384 1ba81399 .config log report info BUG: Dentry still in use [unmount of devpts devpts]
ci2-android-5-4-kasan 2021/03/20 05:57 android12-5.4 8c688c5793e7 3d01c4de .config log report info BUG: Dentry still in use [unmount of devpts devpts]
ci2-android-5-4-kasan 2021/02/04 20:53 android12-5.4 1e5f5a14faba 42b90a7c .config log report info BUG: Dentry still in use [unmount of devpts devpts]
ci2-android-5-4-kasan 2021/01/11 01:26 android12-5.4 c9951e5d80dd 2c1f2513 .config log report info
ci2-android-5-4-kasan 2021/01/02 20:30 android12-5.4 e627b02af655 79264ae3 .config log report info
ci2-android-5-4-kasan 2021/01/01 07:42 android12-5.4 e627b02af655 79264ae3 .config log report info
ci2-android-5-4-kasan 2020/12/22 20:47 android12-5.4 8657d5d6282f 04201c06 .config log report info
ci2-android-5-4-kasan 2020/12/21 14:17 android12-5.4 cd5f5cb9fe67 04201c06 .config log report info
* Struck through repros no longer work on HEAD.