#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 939f15e640f193616691d3bcde0089760e75b0d3

Signed-off-by: Prithvi Tambewagh <activprithvi@gmail.com>
---
 fs/ocfs2/suballoc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 6ac4dcd54588..f4e4ef08e0f9 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -1992,6 +1992,13 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
 	}
 
 	cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
+	if (!le16_to_cpu(cl->cl_next_free_rec) ||
+		le16_to_cpu(cl->cl_next_free_rec) > le16_to_cpu(cl->cl_count)) {
+		status = ocfs2_error(ac->ac_inode->i_sb,
+				     "Chain allocator dinode %llu has 0 chains\n",
+				     (unsigned long long)le64_to_cpu(fe->i_blkno));
+		goto bail;
+	}
 
 	victim = ocfs2_find_victim_chain(cl);
 	ac->ac_chain = victim;

base-commit: 939f15e640f193616691d3bcde0089760e75b0d3
-- 
2.34.1

On 2025/12/1 15:35, Prithvi Tambewagh wrote:
> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 939f15e640f193616691d3bcde0089760e75b0d3
> 
> Signed-off-by: Prithvi Tambewagh <activprithvi@gmail.com>
> ---
>  fs/ocfs2/suballoc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
> index 6ac4dcd54588..f4e4ef08e0f9 100644
> --- a/fs/ocfs2/suballoc.c
> +++ b/fs/ocfs2/suballoc.c
> @@ -1992,6 +1992,13 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
>  	}
>  
>  	cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
> +	if (!le16_to_cpu(cl->cl_next_free_rec) ||
> +		le16_to_cpu(cl->cl_next_free_rec) > le16_to_cpu(cl->cl_count)) {
	    ^
Prefer to align here.

BTW, the prefix for patch title can be "ocfs2: " only.

Joseph

> +		status = ocfs2_error(ac->ac_inode->i_sb,
> +				     "Chain allocator dinode %llu has 0 chains\n",
> +				     (unsigned long long)le64_to_cpu(fe->i_blkno));
> +		goto bail;
> +	}
>  
>  	victim = ocfs2_find_victim_chain(cl);
>  	ac->ac_chain = victim;
> 
> base-commit: 939f15e640f193616691d3bcde0089760e75b0d3

> #syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 939f15e640f193616691d3bcde0089760e75b0d3

I see the command but can't find the corresponding bug.
Please resend the email to syzbot+HASH@syzkaller.appspotmail.com address
that is the sender of the bug report (also present in the Reported-by tag).

>
> Signed-off-by: Prithvi Tambewagh <activprithvi@gmail.com>
> ---
>  fs/ocfs2/suballoc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
> index 6ac4dcd54588..f4e4ef08e0f9 100644
> --- a/fs/ocfs2/suballoc.c
> +++ b/fs/ocfs2/suballoc.c
> @@ -1992,6 +1992,13 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
>  	}
>  
>  	cl = (struct ocfs2_chain_list *) &fe->id2.i_chain;
> +	if (!le16_to_cpu(cl->cl_next_free_rec) ||
> +		le16_to_cpu(cl->cl_next_free_rec) > le16_to_cpu(cl->cl_count)) {
> +		status = ocfs2_error(ac->ac_inode->i_sb,
> +				     "Chain allocator dinode %llu has 0 chains\n",
> +				     (unsigned long long)le64_to_cpu(fe->i_blkno));
> +		goto bail;
> +	}
>  
>  	victim = ocfs2_find_victim_chain(cl);
>  	ac->ac_chain = victim;
>
> base-commit: 939f15e640f193616691d3bcde0089760e75b0d3
> -- 
> 2.34.1
>
> -- 
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