Message-ID: <67ab779b.050a0220.3d72c.0064.GAE@google.com>
Date: Tue, 11 Feb 2025 08:15:23 -0800
From: syzbot <syzbot+2ff67872645e5b5ebdd5@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, brauner@...nel.org, jack@...e.cz, 
	linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, mjguzik@...il.com, 
	syzkaller-bugs@...glegroups.com, tytso@....edu, viro@...iv.linux.org.uk
Subject: [syzbot] [ext4?] WARNING in __ext4_iget

Hello,

syzbot found the following issue on:

HEAD commit:    7ee983c850b4 Merge tag 'drm-fixes-2025-02-08' of https://g..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=107e4bdf980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ec3c160c5cabe70b
dashboard link: https://syzkaller.appspot.com/bug?extid=2ff67872645e5b5ebdd5
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12d1e1b0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14f1ddf8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/52091eb5b16c/disk-7ee983c8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4aa605b3aa80/vmlinux-7ee983c8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/af16dc4bb19a/bzImage-7ee983c8.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/115f05fb40e2/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=10f1ddf8580000)

The issue was bisected to:

commit 37d11cfc63604b3886308e2111d845d148ced8bc
Author: Mateusz Guzik <mjguzik@...il.com>
Date:   Tue Feb 4 21:32:07 2025 +0000

    vfs: sanity check the length passed to inode_set_cached_link()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12073df8580000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=11073df8580000
console output: https://syzkaller.appspot.com/x/log.txt?x=16073df8580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2ff67872645e5b5ebdd5@...kaller.appspotmail.com
Fixes: 37d11cfc6360 ("vfs: sanity check the length passed to inode_set_cached_link()")

------------[ cut here ]------------
bad length passed for symlink [/tmp/syz-imagegen2884317625/.] (got 39, expected 29)
WARNING: CPU: 0 PID: 5828 at ./include/linux/fs.h:802 inode_set_cached_link include/linux/fs.h:802 [inline]
WARNING: CPU: 0 PID: 5828 at ./include/linux/fs.h:802 __ext4_iget+0x3aa2/0x4310 fs/ext4/inode.c:5012
Modules linked in:
CPU: 0 UID: 0 PID: 5828 Comm: syz-executor385 Not tainted 6.14.0-rc1-syzkaller-00181-g7ee983c850b4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:inode_set_cached_link include/linux/fs.h:802 [inline]
RIP: 0010:__ext4_iget+0x3aa2/0x4310 fs/ext4/inode.c:5012
Code: e8 63 19 49 ff c6 05 e9 1a da 0d 01 90 8b 95 10 ff ff ff 44 89 e1 48 c7 c7 40 4b 85 8b 48 8b b5 f8 fe ff ff e8 8f 57 09 ff 90 <0f> 0b 90 90 e9 2d fd ff ff e8 30 57 ab ff e9 f6 e6 ff ff e8 06 56
RSP: 0018:ffffc90003ca7810 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff888077bd8ca4 RCX: ffffffff817a1159
RDX: ffff888034e01e00 RSI: ffffffff817a1166 RDI: 0000000000000001
RBP: ffffc90003ca7960 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 000000000000001d
R13: 0000000000000000 R14: 0000000000002000 R15: ffff888077bd8c98
FS:  00005555696a5380(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555696be778 CR3: 00000000743ae000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 ext4_lookup+0x37e/0x730 fs/ext4/namei.c:1813
 __lookup_slow+0x252/0x470 fs/namei.c:1793
 lookup_slow fs/namei.c:1810 [inline]
 walk_component+0x350/0x5b0 fs/namei.c:2114
 lookup_last fs/namei.c:2612 [inline]
 path_lookupat+0x17f/0x770 fs/namei.c:2636
 filename_lookup+0x221/0x5f0 fs/namei.c:2665
 user_path_at+0x3a/0x60 fs/namei.c:3072
 ksys_umount fs/namespace.c:2071 [inline]
 __do_sys_umount fs/namespace.c:2079 [inline]
 __se_sys_umount fs/namespace.c:2077 [inline]
 __x64_sys_umount+0x10b/0x1a0 fs/namespace.c:2077
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd6ca0f8487
Code: 07 00 48 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 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffd3ce25b68 EFLAGS: 00000202 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd6ca0f8487
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd3ce25c20
RBP: 00007ffd3ce25c20 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000202 R12: 00007ffd3ce26d10
R13: 00005555696b6740 R14: 0000000000000001 R15: 431bde82d7b634db
 </TASK>


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the report is already addressed, let syzbot know by replying with:
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