Re: [syzbot] [jfs?] UBSAN: array-index-out-of-bounds in diNewExt

syzbot
2023-12-10T07:36:12Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
UBSAN: array-index-out-of-bounds in diNewExt

loop0: detected capacity change from 0 to 32768
agno: -878706688, ipimap: ffff88806b342930, iagp: ffff888024d4f000, sbi: ffff888016657a00, agl2s: 13
agno: -878706688, ipimap: ffff88806b342930, iagp: ffff888024d4f000, sbi: ffff888016657a00, agl2s: 13
================================================================================
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_imap.c:2367:2
index -878706688 is out of range for type 'struct iagctl[128]'
CPU: 0 PID: 5481 Comm: syz-executor.0 Not tainted 6.7.0-rc4-syzkaller-00009-gbee0e7762ad2-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
ubsan_epilogue lib/ubsan.c:217 [inline]
__ubsan_handle_out_of_bounds+0x11c/0x150 lib/ubsan.c:348
diNewExt+0x3b39/0x3e00 fs/jfs/jfs_imap.c:2367
diAllocExt fs/jfs/jfs_imap.c:1949 [inline]
diAllocAG+0xbe8/0x1e50 fs/jfs/jfs_imap.c:1666
diAlloc+0x1d3/0x1760 fs/jfs/jfs_imap.c:1587
ialloc+0x8f/0x900 fs/jfs/jfs_inode.c:56
jfs_mkdir+0x1c5/0xb90 fs/jfs/namei.c:225
vfs_mkdir+0x2f1/0x4b0 fs/namei.c:4106
do_mkdirat+0x264/0x3a0 fs/namei.c:4129
__do_sys_mkdirat fs/namei.c:4144 [inline]
__se_sys_mkdirat fs/namei.c:4142 [inline]
__x64_sys_mkdirat+0x89/0xa0 fs/namei.c:4142
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x45/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f857287b5e7
Code: 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f8571bfdee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f857287b5e7
RDX: 00000000000001ff RSI: 0000000020000140 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000140
R13: 00007f8571bfdf40 R14: 0000000000000000 R15: 0000000000000000
</TASK>
================================================================================

Tested on:

commit: bee0e776 Merge tag 'for-linus-iommufd' of git://git.ke..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=135fd132e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=b45dfd882e46ec91
dashboard link: https://syzkaller.appspot.com/bug?extid=553d90297e6d2f50dbc7
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=10668e46e80000