[syzbot] [ocfs2?] WARNING in __ocfs2_decrease_refcount

[syzbot <syzbot+3ef989aae096b30f1663@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    e1914add2799 Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15d62196580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7f195f6be48c12ec
dashboard link: https://syzkaller.appspot.com/bug?extid=3ef989aae096b30f1663
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-e1914add.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/cfc9d48b6e76/vmlinux-e1914add.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e7ac48dd4788/bzImage-e1914add.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3ef989aae096b30f1663@syzkaller.appspotmail.com

------------[ cut here ]------------
memset: detected buffer overflow: 384 byte write of buffer size 16
WARNING: lib/string_helpers.c:1037 at __fortify_report+0x6b/0xa0 lib/string_helpers.c:1036, CPU#0: syz.0.0/5331
Modules linked in:
CPU: 0 UID: 0 PID: 5331 Comm: syz.0.0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__fortify_report+0x89/0xa0 lib/string_helpers.c:1036
Code: e8 7c 6b 7e fd 48 8d 3d 45 8f 87 0b 45 84 e4 49 8b 37 48 c7 c0 c0 0e 28 8c 48 c7 c1 e0 0e 28 8c 48 0f 44 c8 4c 89 f2 49 89 d8 <67> 48 0f b9 3a 5b 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc cc cc cc
RSP: 0018:ffffc90003076848 EFLAGS: 00010202
RAX: ffffffff8c280ec0 RBX: 0000000000000010 RCX: ffffffff8c280ee0
RDX: 0000000000000180 RSI: ffffffff8c280d80 RDI: ffffffff903bc0c0
RBP: 000000000000000f R08: 0000000000000010 R09: 1ffffffff2061b5e
R10: dffffc0000000000 R11: fffffbfff2061b5f R12: 0000000000000001
R13: 1ffff1100ab75510 R14: 0000000000000180 R15: ffffffff8c280bb8
FS:  0000555562e72540(0000) GS:ffff88808c881000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000001fc6a000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __fortify_panic+0x9/0x10 lib/string_helpers.c:1043
 fortify_memset_chk include/linux/fortify-string.h:495 [inline]
 ocfs2_remove_refcount_extent fs/ocfs2/refcounttree.c:2134 [inline]
 ocfs2_decrease_refcount_rec fs/ocfs2/refcounttree.c:2203 [inline]
 __ocfs2_decrease_refcount+0x1990/0x19e0 fs/ocfs2/refcounttree.c:2249
 ocfs2_decrease_refcount+0x59c/0x7d0 fs/ocfs2/refcounttree.c:2312
 ocfs2_remove_btree_range+0x125b/0x1610 fs/ocfs2/alloc.c:5800
 ocfs2_commit_truncate+0xbb8/0x2310 fs/ocfs2/alloc.c:7383
 ocfs2_truncate_for_delete fs/ocfs2/inode.c:701 [inline]
 ocfs2_wipe_inode fs/ocfs2/inode.c:868 [inline]
 ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
 ocfs2_evict_inode+0x1023/0x43b0 fs/ocfs2/inode.c:1299
 evict+0x61e/0xb10 fs/inode.c:841
 ocfs2_dentry_iput+0x24d/0x390 fs/ocfs2/dcache.c:407
 __dentry_kill+0x1a2/0x690 fs/dcache.c:718
 finish_dput+0xc9/0x480 fs/dcache.c:927
 __fput+0x691/0xa60 fs/file_table.c:518
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f402a59ce59
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffc44472f8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f402a817da0 RCX: 00007f402a59ce59
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f402a817da0 R08: 00007f402a816038 R09: 0000000000000000
R10: 0000000000dcaba0 R11: 0000000000000246 R12: 00000000000156b7
R13: 00007f402a81609c R14: 0000000000015685 R15: 00007f402a816090
 </TASK>
----------------
Code disassembly (best guess):
   0:	e8 7c 6b 7e fd       	call   0xfd7e6b81
   5:	48 8d 3d 45 8f 87 0b 	lea    0xb878f45(%rip),%rdi        # 0xb878f51
   c:	45 84 e4             	test   %r12b,%r12b
   f:	49 8b 37             	mov    (%r15),%rsi
  12:	48 c7 c0 c0 0e 28 8c 	mov    $0xffffffff8c280ec0,%rax
  19:	48 c7 c1 e0 0e 28 8c 	mov    $0xffffffff8c280ee0,%rcx
  20:	48 0f 44 c8          	cmove  %rax,%rcx
  24:	4c 89 f2             	mov    %r14,%rdx
  27:	49 89 d8             	mov    %rbx,%r8
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	41 5c                	pop    %r12
  32:	41 5e                	pop    %r14
  34:	41 5f                	pop    %r15
  36:	5d                   	pop    %rbp
  37:	c3                   	ret
  38:	cc                   	int3
  39:	cc                   	int3
  3a:	cc                   	int3
  3b:	cc                   	int3
  3c:	cc                   	int3
  3d:	cc                   	int3
  3e:	cc                   	int3
  3f:	cc                   	int3


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