linux-kernel - [syzbot] [mm?] [bcachefs?] UBSAN: shift-out-of-bounds in xas

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Message-ID: <67a4eae3.050a0220.65602.0002.GAE@google.com>
Date: Thu, 06 Feb 2025 09:01:23 -0800
From: syzbot <syzbot+8ae0902c29b15a27a4ee@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, hughd@...gle.com, kent.overstreet@...ux.dev, 
	linux-bcachefs@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] [bcachefs?] UBSAN: shift-out-of-bounds in xas_reload

Hello,

syzbot found the following issue on:

HEAD commit:    92514ef226f5 Merge tag 'for-6.14-rc1-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14761318580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1909f2f0d8e641ce
dashboard link: https://syzkaller.appspot.com/bug?extid=8ae0902c29b15a27a4ee
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17df01b0580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-92514ef2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c4d8b91f8769/vmlinux-92514ef2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c24ec4365966/bzImage-92514ef2.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/2f20c9ca14a0/mount_2.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8ae0902c29b15a27a4ee@...kaller.appspotmail.com

------------[ cut here ]------------
UBSAN: shift-out-of-bounds in ./include/linux/xarray.h:1604:27
shift exponent 192 is too large for 64-bit type 'unsigned long'
CPU: 0 UID: 0 PID: 5696 Comm: syz.4.33 Not tainted 6.14.0-rc1-syzkaller-00034-g92514ef226f5 #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
 xas_reload+0x434/0x470 include/linux/xarray.h:1604
 find_get_entry mm/filemap.c:2032 [inline]
 find_lock_entries+0x2d4/0xbb0 mm/filemap.c:2119
 shmem_undo_range+0x2d4/0x1820 mm/shmem.c:1094
 shmem_truncate_range mm/shmem.c:1224 [inline]
 shmem_evict_inode+0x29b/0xa80 mm/shmem.c:1352
 evict+0x4e8/0x9a0 fs/inode.c:796
 __dentry_kill+0x20d/0x630 fs/dcache.c:643
 dput+0x19f/0x2b0 fs/dcache.c:885
 __fput+0x60b/0x9f0 fs/file_table.c:456
 __do_sys_close fs/open.c:1579 [inline]
 __se_sys_close fs/open.c:1564 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1564
 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: 0033:0x7f4dd9f8ba4a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24
RSP: 002b:00007f4ddae87e00 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 00000000ffffffff RCX: 00007f4dd9f8ba4a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000005939
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000004
R13: 00007f4ddae87ef0 R14: 00007f4ddae87eb0 R15: 00007f4dd0c00000
 </TASK>
---[ end trace ]---


---
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