[syzbot] [ocfs2?] UBSAN: array-index-out-of-bounds in ocfs2_grow_tree (2)

Hello,

syzbot found the following issue on:

HEAD commit:    faeab166167f Merge tag 'pinctrl-v7.1-1' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1765ffca580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d120b114be21f79
dashboard link: https://syzkaller.appspot.com/bug?extid=be16e33db01e6644db7a
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-faeab166.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/756ff8e81a3b/vmlinux-faeab166.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c4cb66569b5/bzImage-faeab166.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

loop0: detected capacity change from 0 to 32768
=======================================================
WARNING: The mand mount option has been deprecated and
         and is ignored by this kernel. Remove the mand
         option from the mount to silence this warning.
=======================================================
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
(syz.0.0,5330,0):ocfs2_check_set_options:1244 ERROR: Invalid heartbeat mount options
loop0: detected capacity change from 32768 to 32767
(syz.0.0,5330,0):ocfs2_validate_inode_block:1449 ERROR: Invalid dinode #17058: Corrupt state (nlink = 0 or mode = 0) detected!
(syz.0.0,5330,0):ocfs2_assign_bh:2417 ERROR: status = -117
(syz.0.0,5330,0):ocfs2_inode_lock_full_nested:2512 ERROR: status = -117
(syz.0.0,5330,0):ocfs2_reflink_inodes_lock:4747 ERROR: status = -117
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/ocfs2/alloc.c:1112:9
index -1 is out of range for type 'struct ocfs2_extent_rec[] __counted_by(l_count)' (aka 'struct ocfs2_extent_rec[]')
CPU: 0 UID: 0 PID: 5330 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
 ocfs2_sum_rightmost_rec fs/ocfs2/alloc.c:1112 [inline]
 ocfs2_shift_tree_depth fs/ocfs2/alloc.c:1433 [inline]
 ocfs2_grow_tree+0x37fc/0x4060 fs/ocfs2/alloc.c:1581
 ocfs2_insert_extent+0xc67/0x1700 fs/ocfs2/alloc.c:4764
 ocfs2_add_clusters_in_btree+0x678/0xff0 fs/ocfs2/alloc.c:4866
 ocfs2_add_inode_data+0xe7/0x140 fs/ocfs2/file.c:551
 ocfs2_write_cluster fs/ocfs2/aops.c:1117 [inline]
 ocfs2_write_cluster_by_desc+0x566/0x1de0 fs/ocfs2/aops.c:1221
 ocfs2_write_begin_nolock+0x3305/0x41a0 fs/ocfs2/aops.c:1797
 ocfs2_write_begin+0x1c5/0x320 fs/ocfs2/aops.c:1885
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4324
 ocfs2_file_write_iter+0x1663/0x1e70 fs/ocfs2/file.c:2476
 iter_file_splice_write+0x9a1/0x10f0 fs/splice.c:736
 do_splice_from fs/splice.c:936 [inline]
 direct_splice_actor+0x101/0x160 fs/splice.c:1159
 splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1103
 do_splice_direct_actor fs/splice.c:1202 [inline]
 do_splice_direct+0x195/0x290 fs/splice.c:1228
 vfs_copy_file_range+0xb02/0x1370 fs/read_write.c:1634
 __do_sys_copy_file_range fs/read_write.c:1683 [inline]
 __se_sys_copy_file_range+0x2fb/0x480 fs/read_write.c:1650
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5a2459c819
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:00007f5a25523fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000146
RAX: ffffffffffffffda RBX: 00007f5a24815fa0 RCX: 00007f5a2459c819
RDX: 0000000000000004 RSI: 00002000000001c0 RDI: 0000000000000005
RBP: 00007f5a24632c91 R08: ffffffffa003e45b R09: 0700000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5a24816038 R14: 00007f5a24815fa0 R15: 00007ffc179ae578
 </TASK>
---[ end trace ]---


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