linux-kernel - [syzbot] [ext4?] WARNING in ext4_xattr_inode_dec_ref

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Message-ID: <68da6b45.050a0220.1696c6.0015.GAE@google.com>
Date: Mon, 29 Sep 2025 04:19:33 -0700
From: syzbot <syzbot+55cb5d2db550fbc52264@...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_dec_ref_all

Hello,

syzbot found the following issue on:

HEAD commit:    b5a4da2c459f Add linux-next specific files for 20250924
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=12abed34580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fc64d939cce41d2
dashboard link: https://syzkaller.appspot.com/bug?extid=55cb5d2db550fbc52264
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/127c931e6696/disk-b5a4da2c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cf4957abd39e/vmlinux-b5a4da2c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/860d3ac61bac/bzImage-b5a4da2c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+55cb5d2db550fbc52264@...kaller.appspotmail.com

loop7: detected capacity change from 0 to 512
EXT4-fs warning (device loop7): ext4_xattr_inode_get:542: inode #11: comm syz.7.2381: ea_inode file size=0 entry size=6
------------[ cut here ]------------
EA inode 11 i_nlink=2
WARNING: fs/ext4/xattr.c:1053 at ext4_xattr_inode_update_ref+0x534/0x5d0 fs/ext4/xattr.c:1051, CPU#0: syz.7.2381/16796
Modules linked in:
CPU: 0 UID: 0 PID: 16796 Comm: syz.7.2381 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RAX: 13d1ab016548b300 RBX: dffffc0000000000 RCX: 0000000000080000
RDX: ffffc9000cc0d000 RSI: 0000000000008560 RDI: 0000000000008561
RBP: ffffc9000ba57390 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff1c3a65c R12: ffff8880546a1f90
R13: 1ffff1100a8d43f2 R14: 00000000ffffffff R15: 000000000000000b
FS:  00007f560bbf66c0(0000) GS:ffff888125a03000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fab211156c0 CR3: 000000005ffc2000 CR4: 00000000003526f0
DR0: 0000000000000008 DR1: 0000000000000002 DR2: 0000000000000081
DR3: ffffffffefffff14 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ext4_xattr_inode_dec_ref fs/ext4/xattr.c:1076 [inline]
 ext4_xattr_inode_dec_ref_all+0x867/0xda0 fs/ext4/xattr.c:1218
 ext4_xattr_delete_inode+0xa4c/0xc10 fs/ext4/xattr.c:2942
 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:474
 __ext4_fill_super fs/ext4/super.c:5615 [inline]
 ext4_fill_super+0x57df/0x6090 fs/ext4/super.c:5734
 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+0x302/0x9e0 fs/namespace.c:3725
 do_mount fs/namespace.c:4048 [inline]
 __do_sys_mount fs/namespace.c:4236 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4213
 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: 0033:0x7f560d99066a
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:00007f560bbf5e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f560bbf5ef0 RCX: 00007f560d99066a
RDX: 0000200000000180 RSI: 00002000000001c0 RDI: 00007f560bbf5eb0
RBP: 0000200000000180 R08: 00007f560bbf5ef0 R09: 0000000000800700
R10: 0000000000800700 R11: 0000000000000246 R12: 00002000000001c0
R13: 00007f560bbf5eb0 R14: 0000000000000473 R15: 0000200000000680
 </TASK>


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