linux-kernel - [syzbot] [gfs2?] UBSAN: shift-out-of-bounds in gfs2_dir

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Message-ID: <67746cbc.050a0220.25abdd.0951.GAE@google.com>
Date: Tue, 31 Dec 2024 14:14:20 -0800
From: syzbot <syzbot+8f27157166450172d406@...kaller.appspotmail.com>
To: agruenba@...hat.com, gfs2@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	syzkaller-bugs@...glegroups.com
Subject: [syzbot] [gfs2?] UBSAN: shift-out-of-bounds in gfs2_dir_read

Hello,

syzbot found the following issue on:

HEAD commit:    8379578b11d5 Merge tag 'for-v6.13-rc' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10917adf980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d269ef41b9262400
dashboard link: https://syzkaller.appspot.com/bug?extid=8f27157166450172d406
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-8379578b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/46152cb37ce6/vmlinux-8379578b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b14facfd62b8/bzImage-8379578b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f27157166450172d406@...kaller.appspotmail.com

loop0: detected capacity change from 0 to 32768
gfs2: fsid=syz:syz: Trying to join cluster "lock_nolock", "syz:syz"
gfs2: fsid=syz:syz: Now mounting FS (format 1801)...
gfs2: fsid=syz:syz.0: journal 0 mapped with 1 extents in 0ms
gfs2: fsid=syz:syz.0: first mount done, others may mount
------------[ cut here ]------------
UBSAN: shift-out-of-bounds in fs/gfs2/dir.c:1544:15
shift exponent 32 is too large for 32-bit type 'u32' (aka 'unsigned int')
CPU: 0 UID: 0 PID: 5323 Comm: syz.0.0 Not tainted 6.13.0-rc4-syzkaller-00069-g8379578b11d5 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:231 [inline]
 __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468
 dir_e_read fs/gfs2/dir.c:1544 [inline]
 gfs2_dir_read+0x1a50/0x1af0 fs/gfs2/dir.c:1585
 gfs2_readdir+0x14b/0x1b0 fs/gfs2/file.c:116
 iterate_dir+0x571/0x800 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x1e2/0x4b0 fs/readdir.c:389
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f60b3185d29
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f60b3f65038 EFLAGS: 00000246 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 00007f60b3375fa0 RCX: 00007f60b3185d29
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f60b3201b08 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f60b3375fa0 R15: 00007fffa2e8df68
 </TASK>
---[ end trace ]---


---
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