[syzbot] [ext4?] WARNING in inode_set_cached_link

[syzbot] [ext4?] WARNING in inode_set_cached_link

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    808eb958781e Add linux-next specific files for 20250206
git tree:       linux-next
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14a46df8580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=88b25e5d30d576e4
dashboard link: https://syzkaller.appspot.com/bug?extid=2cca5ef7e5ed862c0799
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=161241b0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16ee80e4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/493ef93f2e5f/disk-808eb958.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b41757cd41c9/vmlinux-808eb958.xz
kernel image: https://storage.googleapis.com/syzbot-assets/24f456104aad/bzImage-808eb958.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/fb0901f433df/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2cca5ef7e5ed862c0799@syzkaller.appspotmail.com

EXT4-fs warning (device loop0): ext4_enable_quotas:7145: Failed to enable quota tracking (type=1, err=-22, ino=4). Please run e2fsck to fix.
EXT4-fs (loop0): Cannot turn on quotas: error -22
------------[ cut here ]------------
bad length passed for symlink [
�\x01] (got 9000, expected 3)
WARNING: CPU: 1 PID: 5832 at ./include/linux/fs.h:803 inode_set_cached_link+0xd0/0x110 include/linux/fs.h:802
Modules linked in:
CPU: 1 UID: 0 PID: 5832 Comm: syz-executor433 Not tainted 6.14.0-rc1-next-20250206-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
RIP: 0010:inode_set_cached_link+0xd0/0x110 include/linux/fs.h:802
Code: 41 5f 5d c3 cc cc cc cc e8 ed 1b 44 ff c6 05 b5 51 8a 0d 01 90 48 c7 c7 20 dc 1d 8c 4c 89 f6 44 89 fa 89 e9 e8 d1 c7 04 ff 90 <0f> 0b 90 90 e9 6a ff ff ff 89 f9 80 e1 07 80 c1 03 38 c1 7c a1 e8
RSP: 0018:ffffc90003967658 EFLAGS: 00010246
RAX: b92553c73f221b00 RBX: ffff88807b3a02b0 RCX: ffff88802ef89e00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000003 R08: ffffffff81803292 R09: fffffbfff1cfa5b8
R10: dffffc0000000000 R11: fffffbfff1cfa5b8 R12: ffff88807b3a02b0
R13: dffffc0000000000 R14: ffff88807b3a0000 R15: 0000000000002328
FS:  00005555558f7380(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff832fc000 CR3: 0000000028d14000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __ext4_iget+0x2ea4/0x3f30 fs/ext4/inode.c:5000
 ext4_orphan_get+0x1bb/0x5f0 fs/ext4/ialloc.c:1389
 ext4_orphan_cleanup+0xa19/0x13d0 fs/ext4/orphan.c:467
 __ext4_fill_super fs/ext4/super.c:5602 [inline]
 ext4_fill_super+0x5dd5/0x6760 fs/ext4/super.c:5722
 get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
 do_new_mount+0x2be/0xb40 fs/namespace.c:3659
 do_mount fs/namespace.c:3999 [inline]
 __do_sys_mount fs/namespace.c:4210 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4187
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc90683b93a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fff832fba58 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff832fba70 RCX: 00007fc90683b93a
RDX: 0000200000000080 RSI: 0000200000000000 RDI: 00007fff832fba70
RBP: 0000200000000000 R08: 00007fff832fbab0 R09: 00000000000004f5
R10: 000000000200801f R11: 0000000000000202 R12: 0000200000000080
R13: 0000000000000004 R14: 0000000000000003 R15: 00007fff832fbab0
 </TASK>


---
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Re: [syzbot] [ext4?] WARNING in inode_set_cached_link

[syzbot]

syzbot has bisected this issue to:

commit 6408a56623761f969537b421d99f045a4cc955b9
Author: Mateusz Guzik <mjguzik@gmail.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=152ffca4580000
start commit:   808eb958781e Add linux-next specific files for 20250206
git tree:       linux-next
final oops:     https://syzkaller.appspot.com/x/report.txt?x=172ffca4580000
console output: https://syzkaller.appspot.com/x/log.txt?x=132ffca4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=88b25e5d30d576e4
dashboard link: https://syzkaller.appspot.com/bug?extid=2cca5ef7e5ed862c0799
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=161241b0580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16ee80e4580000

Reported-by: syzbot+2cca5ef7e5ed862c0799@syzkaller.appspotmail.com
Fixes: 6408a5662376 ("vfs: sanity check the length passed to inode_set_cached_link()")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Re: [syzbot] [ext4?] WARNING in inode_set_cached_link

[Mateusz Guzik]

For posterity this is expected, the ex4 fix is here:
https://lore.kernel.org/linux-hardening/67a3b38f.050a0220.19061f.05ea.GAE@google.com/T/#mb782935cc6926dd5642984189d922135f023ec43

On Sat, Feb 8, 2025 at 7:21 PM syzbot
<syzbot+2cca5ef7e5ed862c0799@syzkaller.appspotmail.com> wrote:
>
> syzbot has bisected this issue to:
>
> commit 6408a56623761f969537b421d99f045a4cc955b9
> Author: Mateusz Guzik <mjguzik@gmail.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=152ffca4580000
> start commit:   808eb958781e Add linux-next specific files for 20250206
> git tree:       linux-next
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=172ffca4580000
> console output: https://syzkaller.appspot.com/x/log.txt?x=132ffca4580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=88b25e5d30d576e4
> dashboard link: https://syzkaller.appspot.com/bug?extid=2cca5ef7e5ed862c0799
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=161241b0580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16ee80e4580000
>
> Reported-by: syzbot+2cca5ef7e5ed862c0799@syzkaller.appspotmail.com
> Fixes: 6408a5662376 ("vfs: sanity check the length passed to inode_set_cached_link()")
>
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection



-- 
Mateusz Guzik <mjguzik gmail.com>