Message-ID: <6903e7f7.050a0220.3344a1.044c.GAE@google.com>
Date: Thu, 30 Oct 2025 15:34:31 -0700
From: syzbot <syzbot+76916a45d2294b551fd9@...kaller.appspotmail.com>
To: adilger.kernel@...ger.ca, linux-ext4@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] WARNING in ext4_xattr_inode_update_ref (2)

Hello,

syzbot found the following issue on:

HEAD commit:    e53642b87a4f Merge tag 'v6.18-rc3-smb-server-fixes' of git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=150aa32f980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=929790bc044e87d7
dashboard link: https://syzkaller.appspot.com/bug?extid=76916a45d2294b551fd9
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=101f5f34580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=121dbe7c580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-e53642b8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bb13d82854da/vmlinux-e53642b8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f3a72d29f243/bzImage-e53642b8.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/fb4c6b817064/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16191fe2580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+76916a45d2294b551fd9@...kaller.appspotmail.com

EXT4-fs warning (device loop0): ext4_xattr_inode_get:546: inode #11: comm syz.0.17: ea_inode file size=0 entry size=6
EXT4-fs warning (device loop0): ext4_expand_extra_isize_ea:2853: Unable to expand inode 15. Delete some EAs or run e2fsck.
------------[ cut here ]------------
EA inode 11 i_nlink=2
WARNING: CPU: 0 PID: 5496 at fs/ext4/xattr.c:1058 ext4_xattr_inode_update_ref+0x51a/0x5b0 fs/ext4/xattr.c:1056
Modules linked in:
CPU: 0 UID: 0 PID: 5496 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ext4_xattr_inode_update_ref+0x51a/0x5b0 fs/ext4/xattr.c:1056
Code: 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 06 84 c0 0f 85 80 00 00 00 41 8b 17 48 c7 c7 80 1f 80 8b 4c 89 e6 e8 a7 1b f8 fe 90 <0f> 0b 90 90 4c 8b 6c 24 28 e9 59 fe ff ff e8 f3 0b bd 08 44 89 f9
RSP: 0018:ffffc90002847240 EFLAGS: 00010246
RAX: 96417f00249f1400 RBX: 0000000000000001 RCX: ffff88801f648000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffc90002847330 R08: ffff88801fe24293 R09: 1ffff11003fc4852
R10: dffffc0000000000 R11: ffffed1003fc4853 R12: 000000000000000b
R13: ffff8880121df630 R14: 1ffff1100243beb4 R15: ffff8880121df5a0
FS:  000055557b2d3500(0000) GS:ffff88808d733000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd0e033d000 CR3: 000000004bac3000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ext4_xattr_inode_dec_ref fs/ext4/xattr.c:1081 [inline]
 ext4_xattr_inode_dec_ref_all+0x867/0xda0 fs/ext4/xattr.c:1223
 ext4_xattr_delete_inode+0xa4c/0xc10 fs/ext4/xattr.c:2947
 ext4_evict_inode+0xac9/0xee0 fs/ext4/inode.c:271
 evict+0x504/0x9c0 fs/inode.c:810
 ext4_orphan_cleanup+0xc20/0x1460 fs/ext4/orphan.c:470
 __ext4_fill_super fs/ext4/super.c:5617 [inline]
 ext4_fill_super+0x5920/0x61e0 fs/ext4/super.c:5736
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1691
 vfs_get_tree+0x92/0x2b0 fs/super.c:1751
 fc_mount fs/namespace.c:1208 [inline]
 do_new_mount_fc fs/namespace.c:3651 [inline]
 do_new_mount+0x302/0xa10 fs/namespace.c:3727
 do_mount fs/namespace.c:4050 [inline]
 __do_sys_mount fs/namespace.c:4238 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4215
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9e5239076a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd45601928 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffd456019b0 RCX: 00007f9e5239076a
RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007ffd45601970
RBP: 0000200000000180 R08: 00007ffd456019b0 R09: 0000000000800700
R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007ffd45601970 R14: 000000000000046c R15: 0000200000000680
 </TASK>


---
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