syzbot


WARNING: bad unlock balance in ext4_ioctl

Status: upstream: reported C repro on 2023/12/11 20:10
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+412cf01ec1834ce6d161@syzkaller.appspotmail.com
First crash: 196d, last: 27d
Bug presence (1)
Date Name Commit Repro Result
2023/12/12 upstream (ToT) 26aff849438c C [report] WARNING in lock_two_nondirectories
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING: bad unlock balance in ext4_ioctl origin:upstream C 2 22d 196d 0/3 upstream: reported C repro on 2023/12/11 13:43
Fix bisection attempts (5)
Created Duration User Patch Repo Result
2024/05/28 10:34 57m bisect fix linux-6.1.y job log (0) log
2024/04/23 12:57 1h53m bisect fix linux-6.1.y job log (0) log
2024/03/22 10:57 1h11m bisect fix linux-6.1.y job log (0) log
2024/02/21 06:38 58m bisect fix linux-6.1.y job log (0) log
2024/01/11 01:01 54m bisect fix linux-6.1.y job log (0) log

Sample crash report:
EXT4-fs: Ignoring removed bh option
EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
EXT4-fs (loop0): 1 truncate cleaned up
EXT4-fs (loop0): mounted filesystem without journal. Quota mode: none.
=====================================
WARNING: bad unlock balance detected!
6.1.67-syzkaller #0 Not tainted
-------------------------------------
syz-executor311/3545 is trying to release lock (&type->i_mutex_dir_key) at:
[<ffffffff823bfb39>] swap_inode_boot_loader fs/ext4/ioctl.c:513 [inline]
[<ffffffff823bfb39>] __ext4_ioctl fs/ext4/ioctl.c:1424 [inline]
[<ffffffff823bfb39>] ext4_ioctl+0x4249/0x5f60 fs/ext4/ioctl.c:1614
but there are no more locks to release!

other info that might help us debug this:
1 lock held by syz-executor311/3545:
 #0: ffff888072c0e460 (sb_writers#9){.+.+}-{0:0}, at: mnt_want_write_file+0x5a/0x1f0 fs/namespace.c:437

stack backtrace:
CPU: 1 PID: 3545 Comm: syz-executor311 Not tainted 6.1.67-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_unlock_imbalance_bug+0x24e/0x2c0 kernel/locking/lockdep.c:5102
 __lock_release kernel/locking/lockdep.c:5339 [inline]
 lock_release+0x5ad/0xa20 kernel/locking/lockdep.c:5682
 up_write+0x75/0x580 kernel/locking/rwsem.c:1625
 swap_inode_boot_loader fs/ext4/ioctl.c:513 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1424 [inline]
 ext4_ioctl+0x4249/0x5f60 fs/ext4/ioctl.c:1614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe743eb9b39
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe6aa4deb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe6aa4e098 RCX: 00007fe743eb9b39
RDX: 0000000000000000 RSI: 0000000000006611 RDI: 0000000000000004
RBP: 00007fe743f2d610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe6aa4e088 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
------------[ cut here ]------------
DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)): count = 0x0, magic = 0xffff88806fcd8d98, owner = 0x0, curr 0xffff88807d2cd940, list empty
WARNING: CPU: 1 PID: 3545 at kernel/locking/rwsem.c:1372 __up_write kernel/locking/rwsem.c:1371 [inline]
WARNING: CPU: 1 PID: 3545 at kernel/locking/rwsem.c:1372 up_write+0x4f5/0x580 kernel/locking/rwsem.c:1626
Modules linked in:
CPU: 1 PID: 3545 Comm: syz-executor311 Not tainted 6.1.67-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:__up_write kernel/locking/rwsem.c:1371 [inline]
RIP: 0010:up_write+0x4f5/0x580 kernel/locking/rwsem.c:1626
Code: 48 c7 c7 40 d8 eb 8a 48 c7 c6 80 da eb 8a 48 8b 54 24 28 48 8b 4c 24 18 4d 89 e0 4c 8b 4c 24 30 53 e8 df dc e8 ff 48 83 c4 08 <0f> 0b e9 71 fd ff ff 48 c7 c1 a8 73 73 8e 80 e1 07 80 c1 03 38 c1
RSP: 0018:ffffc90003adf840 EFLAGS: 00010292
RAX: dfabf9f051e99f00 RBX: ffffffff8aebd920 RCX: ffff88807d2cd940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003adf910 R08: ffffffff81527dae R09: fffff5200075be69
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000
R13: ffff88806fcd8d98 R14: 1ffff9200075bf10 R15: dffffc0000000000
FS:  0000555555e2a380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000007d4ce000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 swap_inode_boot_loader fs/ext4/ioctl.c:513 [inline]
 __ext4_ioctl fs/ext4/ioctl.c:1424 [inline]
 ext4_ioctl+0x4249/0x5f60 fs/ext4/ioctl.c:1614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe743eb9b39
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe6aa4deb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffe6aa4e098 RCX: 00007fe743eb9b39
RDX: 0000000000000000 RSI: 0000000000006611 RDI: 0000000000000004
RBP: 00007fe743f2d610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffe6aa4e088 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/12/11 22:10 linux-6.1.y e7cddbb41b63 28b24332 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-6-1-kasan WARNING: bad unlock balance in ext4_ioctl
2023/12/11 20:10 linux-6.1.y e7cddbb41b63 28b24332 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan WARNING: bad unlock balance in ext4_ioctl
* Struck through repros no longer work on HEAD.