Re: [PATCH V4 2/2] ocfs2: Fix possible null-ptr-deref in ocfs2_set_buffer_uptodate

[Joseph Qi <joseph.qi@linux.alibaba.com>]

On 8/21/24 2:14 PM, Lizhi Xu wrote:
> When doing cleanup, if flags without OCFS2_BH_READAHEAD, it may trigger
> NULL pointer dereference in the following ocfs2_set_buffer_uptodate() if
> bh is NULL.
> 
> Reported-and-suggested-by: Heming Zhao <heming.zhao@suse.com>
> Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com>

Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> ---
> V3 -> V4: Update comments and subject
> 
>  fs/ocfs2/buffer_head_io.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/buffer_head_io.c b/fs/ocfs2/buffer_head_io.c
> index e62c7e1de4eb..8f714406528d 100644
> --- a/fs/ocfs2/buffer_head_io.c
> +++ b/fs/ocfs2/buffer_head_io.c
> @@ -388,7 +388,8 @@ int ocfs2_read_blocks(struct ocfs2_caching_info *ci, u64 block, int nr,
>  		/* Always set the buffer in the cache, even if it was
>  		 * a forced read, or read-ahead which hasn't yet
>  		 * completed. */
> -		ocfs2_set_buffer_uptodate(ci, bh);
> +		if (bh)
> +			ocfs2_set_buffer_uptodate(ci, bh);
>  	}
>  	ocfs2_metadata_cache_io_unlock(ci);
>