linux-ext4 - [syzbot] [ext4?] KMSAN: uninit-value in htree_dirblock_to

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Date:   Tue, 03 Jan 2023 02:58:38 -0800
From:   syzbot <syzbot+394aa8a792cb99dbc837@...kaller.appspotmail.com>
To:     adilger.kernel@...ger.ca, glider@...gle.com,
        linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, tytso@....edu
Subject: [syzbot] [ext4?] KMSAN: uninit-value in htree_dirblock_to_tree

Hello,

syzbot found the following issue on:

HEAD commit:    5c6259d6d19f kmsan: fix memcpy tests
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=1343a1e4480000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e2f77da22508204e
dashboard link: https://syzkaller.appspot.com/bug?extid=394aa8a792cb99dbc837
compiler:       clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/76b6594632b8/disk-5c6259d6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/81a2113c440e/vmlinux-5c6259d6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fd12d098edab/bzImage-5c6259d6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+394aa8a792cb99dbc837@...kaller.appspotmail.com

[EXT4 FS bs=2048, gc=1, bpg=16384, ipg=32, mo=e000e01c, mo2=0002]
System zones: 0-11
EXT4-fs (loop4): mounted filesystem without journal. Quota mode: none.
=====================================================
BUG: KMSAN: uninit-value in htree_dirblock_to_tree+0x101b/0x1710 fs/ext4/namei.c:1116
 htree_dirblock_to_tree+0x101b/0x1710 fs/ext4/namei.c:1116
 ext4_htree_fill_tree+0x1ac9/0x1cc0 fs/ext4/namei.c:1204
 ext4_dx_readdir fs/ext4/dir.c:597 [inline]
 ext4_readdir+0x53cd/0x6450 fs/ext4/dir.c:142
 iterate_dir+0x3e5/0x9b0
 __do_compat_sys_getdents fs/readdir.c:537 [inline]
 __se_compat_sys_getdents+0x182/0x560 fs/readdir.c:522
 __ia32_compat_sys_getdents+0x8f/0xd0 fs/readdir.c:522
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Local variable hinfo created at:
 ext4_htree_fill_tree+0x5f/0x1cc0 fs/ext4/namei.c:1170
 ext4_dx_readdir fs/ext4/dir.c:597 [inline]
 ext4_readdir+0x53cd/0x6450 fs/ext4/dir.c:142

CPU: 0 PID: 6235 Comm: syz-executor.4 Not tainted 6.1.0-syzkaller-64311-g5c6259d6d19f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================

---
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