[syzbot] WARNING in bio_free

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fdcbcd1348f4 Add linux-next specific files for 20220331
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=16c815bb700000
kernel config: https://syzkaller.appspot.com/x/.config?x=366ab475940a4177
dashboard link: https://syzkaller.appspot.com/bug?extid=e08de3db8be67b2a01b0
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=131015d7700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14807cf7700000

The issue was bisected to:

commit 57c47b42f4545b5f8fa288f190c0d68f96bc477f
Author: Christoph Hellwig <h...@lst.de>
Date: Tue Mar 8 06:15:50 2022 +0000

block: turn bio_kmalloc into a simple kmalloc wrapper

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1567f79b700000
final oops: https://syzkaller.appspot.com/x/report.txt?x=1767f79b700000
console output: https://syzkaller.appspot.com/x/log.txt?x=1367f79b700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e08de3...@syzkaller.appspotmail.com
Fixes: 57c47b42f454 ("block: turn bio_kmalloc into a simple kmalloc wrapper")

loop0: detected capacity change from 0 to 8
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3587 at block/bio.c:229 bio_free+0xe8/0x120 block/bio.c:229
Modules linked in:
CPU: 1 PID: 3587 Comm: syz-executor393 Not tainted 5.17.0-next-20220331-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bio_free+0xe8/0x120 block/bio.c:229
Code: fa 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03 7e 20 8b 45 08 48 83 c4 08 48 29 c3 48 89 df 5b 5d e9 fd be cb fd e8 a8 af a3 fd <0f> 0b e9 51 ff ff ff 48 89 34 24 e8 e8 57 ef fd 48 8b 34 24 eb d1
RSP: 0018:ffffc900038efac0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffff8880241c7f00 RCX: 0000000000000000
RDX: ffff888019410000 RSI: ffffffff83d57848 RDI: ffff8880241c7f80
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff83d57915 R11: 0000000000000000 R12: 0000000000000060
R13: 0000000000000060 R14: 0000000000001000 R15: 0000000000000060
FS: 0000555556045300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffc4e7ecd20 CR3: 000000007554f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
bio_put+0x20e/0x3b0 block/bio.c:754
squashfs_read_data+0x2ce/0xed0 fs/squashfs/block.c:221
squashfs_read_table+0x184/0x1f0 fs/squashfs/cache.c:432
squashfs_fill_super+0x337/0x2690 fs/squashfs/super.c:184
get_tree_bdev+0x440/0x760 fs/super.c:1292
vfs_get_tree+0x89/0x2f0 fs/super.c:1497
do_new_mount fs/namespace.c:3040 [inline]
path_mount+0x1320/0x1fa0 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__x64_sys_mount+0x27f/0x300 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f5ae6a070da
Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe7a847f68 EFLAGS: 00000282 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe7a847fc0 RCX: 00007f5ae6a070da
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe7a847f80
RBP: 00007ffe7a847f80 R08: 00007ffe7a847fc0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000282 R12: 0000000020000218
R13: 0000000000000003 R14: 0000000000000004 R15: 0000000000000001
</TASK>


---
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Christoph Hellwig]

#syz test git://git.infradead.org/users/hch/misc.git squashfs-fix

---end quoted text---

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+e08de3...@syzkaller.appspotmail.com

Tested on:

commit: ea32d892 squashfs: free bios allocated using bio_kmall..
git tree: git://git.infradead.org/users/hch/misc.git squashfs-fix
kernel config: https://syzkaller.appspot.com/x/.config?x=6a82c1abd4cbb9ee

dashboard link: https://syzkaller.appspot.com/bug?extid=e08de3db8be67b2a01b0
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Note: no patches were applied.
Note: testing is done by a robot and is best-effort only.

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.