Message-ID: <66f37319.050a0220.30ac7d.0007.GAE@google.com>
Date: Tue, 24 Sep 2024 19:19:05 -0700
From: syzbot <syzbot+9709e73bae885b05314b@...kaller.appspotmail.com>
To: joseph.qi@...ux.alibaba.com
Cc: jlbec@...lplan.org, joseph.qi@...ux.alibaba.com, 
	linux-kernel@...r.kernel.org, mark@...heh.com, ocfs2-devel@...ts.linux.dev, 
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [ocfs2?] KMSAN: uninit-value in ocfs2_get_block

> This blames p_blkno is uninitialized when ocfs2_extent_map_get_blocks()
> fails.
>
> #syz test: upstream

want either no args or 2 args (repo, branch), got 5

>
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index 1fea43c33b6b..db72b3e924b3 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -156,9 +156,8 @@ int ocfs2_get_block(struct inode *inode, sector_t iblock,
>         err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
>                                           &ext_flags);
>         if (err) {
> -               mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
> -                    "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
> -                    (unsigned long long)p_blkno);
> +               mlog(ML_ERROR, "get_blocks() failed, inode: 0x%p, "
> +                    "block: %llu\n", inode, (unsigned long long)iblock);
>                 goto bail;
>         }
>
> On 9/25/24 9:28 AM, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    baeb9a7d8b60 Merge tag 'sched-rt-2024-09-17' of git://git...
>> git tree:       upstream
>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=172af607980000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=acaa65be5f19fc5a
>> dashboard link: https://syzkaller.appspot.com/bug?extid=9709e73bae885b05314b
>> 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=161e2ca9980000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=151bff00580000
>> 
>> Downloadable assets:
>> disk image: https://storage.googleapis.com/syzbot-assets/cac89ddb3388/disk-baeb9a7d.raw.xz
>> vmlinux: https://storage.googleapis.com/syzbot-assets/ddec90b149ab/vmlinux-baeb9a7d.xz
>> kernel image: https://storage.googleapis.com/syzbot-assets/f8db8244cc07/bzImage-baeb9a7d.xz
>> mounted in repro: https://storage.googleapis.com/syzbot-assets/25ed405f5727/mount_0.gz
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+9709e73bae885b05314b@...kaller.appspotmail.com
>> 
>> OCFS2: ERROR (device loop0): int __ocfs2_find_path(struct ocfs2_caching_info *, struct ocfs2_extent_list *, u32, path_insert_t *, void *): Owner 17 has empty extent list at depth 312
>> On-disk corruption discovered. Please run fsck.ocfs2 once the filesystem is unmounted.
>> OCFS2: Returning error to the calling process.
>> (syz-executor337,5180,0):ocfs2_find_leaf:1940 ERROR: status = -30
>> (syz-executor337,5180,0):ocfs2_get_clusters_nocache:421 ERROR: status = -30
>> (syz-executor337,5180,0):ocfs2_get_clusters:624 ERROR: status = -30
>> (syz-executor337,5180,0):ocfs2_extent_map_get_blocks:671 ERROR: status = -30
>> =====================================================
>> BUG: KMSAN: uninit-value in ocfs2_get_block+0xed2/0x2710 fs/ocfs2/aops.c:159
>>  ocfs2_get_block+0xed2/0x2710 fs/ocfs2/aops.c:159
>>  do_mpage_readpage+0xc45/0x2780 fs/mpage.c:225
>>  mpage_readahead+0x43f/0x840 fs/mpage.c:374
>>  ocfs2_readahead+0x269/0x320 fs/ocfs2/aops.c:381
>>  read_pages+0x193/0x1110 mm/readahead.c:160
>>  page_cache_ra_unbounded+0x901/0x9f0 mm/readahead.c:273
>>  do_page_cache_ra mm/readahead.c:303 [inline]
>>  force_page_cache_ra+0x3b1/0x4b0 mm/readahead.c:332
>>  force_page_cache_readahead mm/internal.h:347 [inline]
>>  generic_fadvise+0x6b0/0xa90 mm/fadvise.c:106
>>  vfs_fadvise mm/fadvise.c:185 [inline]
>>  ksys_fadvise64_64 mm/fadvise.c:199 [inline]
>>  __do_sys_fadvise64 mm/fadvise.c:214 [inline]
>>  __se_sys_fadvise64 mm/fadvise.c:212 [inline]
>>  __x64_sys_fadvise64+0x1fb/0x3a0 mm/fadvise.c:212
>>  x64_sys_call+0xe11/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:222
>>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>>  do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
>>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>> 
>> Local variable p_blkno created at:
>>  ocfs2_get_block+0xc7/0x2710 fs/ocfs2/aops.c:140
>>  do_mpage_readpage+0xc45/0x2780 fs/mpage.c:225
>> 
>> CPU: 0 UID: 0 PID: 5180 Comm: syz-executor337 Not tainted 6.11.0-syzkaller-07341-gbaeb9a7d8b60 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
>> =====================================================
>> 
>> 
>> ---
>> This report is generated by a bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for more information about syzbot.
>> syzbot engineers can be reached at syzkaller@...glegroups.com.
>> 
>> syzbot will keep track of this issue. See:
>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>> 
>> If the report is already addressed, let syzbot know by replying with:
>> #syz fix: exact-commit-title
>> 
>> If you want syzbot to run the reproducer, reply with:
>> #syz test: git://repo/address.git branch-or-commit-hash
>> If you attach or paste a git patch, syzbot will apply it before testing.
>> 
>> If you want to overwrite report's subsystems, reply with:
>> #syz set subsystems: new-subsystem
>> (See the list of subsystem names on the web dashboard)
>> 
>> If the report is a duplicate of another one, reply with:
>> #syz dup: exact-subject-of-another-report
>> 
>> If you want to undo deduplication, reply with:
>> #syz undup
>

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