syzbot


WARNING: refcount bug in btrfs_evict_inode (2)

Status: auto-obsoleted due to no activity on 2024/04/14 05:05
Subsystems: btrfs
[Documentation on labels]
Reported-by: syzbot+3968e6b73153451563ef@syzkaller.appspotmail.com
First crash: 251d, last: 170d
Cause bisection: introduced by (bisect log) [no-op ignored commit]:
commit 9ec5eea5b6acfae7279203097eeec5d02d01d9b7
Author: Jefferson Carpenter <jeffersoncarpenter2@gmail.com>
Date: Sat Feb 13 16:00:15 2021 +0000

  lib/parman: Delete newline

Crash: kernel BUG in clear_inode (log)
Repro: syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [btrfs?] WARNING: refcount bug in btrfs_evict_inode (2) 0 (1) 2023/10/19 23:55
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: refcount bug in btrfs_evict_inode btrfs 2 444d 439d 0/27 auto-obsoleted due to no activity on 2023/08/04 15:13
Last patch testing requests (1)
Created Duration User Patch Repo Result
2023/10/29 23:50 25m retest repro upstream OK log
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/01/05 02:18 2h46m bisect fix upstream job log (0) log
2023/12/04 17:07 2h39m bisect fix upstream job log (0) log

Sample crash report:
------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 1 PID: 5068 at lib/refcount.c:28 refcount_warn_saturate+0x144/0x1b0 lib/refcount.c:28
Modules linked in:
CPU: 1 PID: 5068 Comm: syz-executor.4 Not tainted 6.6.0-rc5-syzkaller-00267-g9a3dad63edbe #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
RIP: 0010:refcount_warn_saturate+0x144/0x1b0 lib/refcount.c:28
Code: 0a 01 48 c7 c7 a0 30 59 8b e8 98 97 15 fd 0f 0b eb a9 e8 cf 74 4f fd c6 05 64 cc 46 0a 01 48 c7 c7 00 31 59 8b e8 7c 97 15 fd <0f> 0b eb 8d e8 b3 74 4f fd c6 05 45 cc 46 0a 01 48 c7 c7 40 30 59
RSP: 0018:ffffc9000410f9c8 EFLAGS: 00010246
RAX: 87d3e0a2fce9e500 RBX: ffff8880283d7108 RCX: ffff88807b601dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81543302 R09: 1ffff1101732516a
R10: dffffc0000000000 R11: ffffed101732516b R12: ffff888027e3c000
R13: 0000000000000000 R14: ffff8880793fa1fe R15: 1ffff1100d13240f
FS:  0000555555d3f480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555555d48938 CR3: 000000002a44c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 btrfs_evict_inode+0x724/0x1000 fs/btrfs/inode.c:5305
 evict+0x2a4/0x620 fs/inode.c:664
 dispose_list fs/inode.c:697 [inline]
 evict_inodes+0x5f8/0x690 fs/inode.c:747
 generic_shutdown_super+0x9d/0x2c0 fs/super.c:672
 kill_anon_super+0x3b/0x70 fs/super.c:1292
 btrfs_kill_super+0x41/0x50 fs/btrfs/super.c:2144
 deactivate_locked_super+0xa4/0x110 fs/super.c:481
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1254
 task_work_run+0x24a/0x300 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x64/0x280 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fdf2aa7de17
Code: b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b0 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007fff45f80ce8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fdf2aa7de17
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007fff45f80da0
RBP: 00007fff45f80da0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff45f81e60
R13: 00007fdf2aac73b9 R14: 000000000006a985 R15: 0000000000000003
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/10/15 23:43 upstream 9a3dad63edbe 6388bc36 .config console log report syz [disk image] [vmlinux] [kernel image] [mounted in repro] ci-upstream-kasan-gce-smack-root WARNING: refcount bug in btrfs_evict_inode
* Struck through repros no longer work on HEAD.