Re: [PATCH] reiserfs: Check the return value from __getblk()

On 6/5/23 16:23, Matthew Wilcox (Oracle) wrote:
> __getblk() can return a NULL pointer if we run out of memory or if
> we try to access beyond the end of the device; check it and handle it
> appropriately.
>
> Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
> Link: https://lore.kernel.org/lkml/CAFcO6XOacq3hscbXevPQP7sXRoYFz34ZdKPYjmd6k5sZuhGFDw@mail.gmail.com/
> Tested-by: butt3rflyh4ck <[email protected]>
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") # probably introduced in 2002
> ---
>   fs/reiserfs/journal.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
> index 4d11d60f493c..dd58e0dca5e5 100644
> --- a/fs/reiserfs/journal.c
> +++ b/fs/reiserfs/journal.c
> @@ -2326,7 +2326,7 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev,
>   	int i, j;
>   
>   	bh = __getblk(dev, block, bufsize);
> -	if (buffer_uptodate(bh))
> +	if (!bh || buffer_uptodate(bh))
>   		return (bh);
>   
>   	if (block + BUFNR > max_block) {
> @@ -2336,6 +2336,8 @@ static struct buffer_head *reiserfs_breada(struct block_device *dev,
>   	j = 1;
>   	for (i = 1; i < blocks; i++) {
>   		bh = __getblk(dev, block + i, bufsize);
> +		if (!bh)
> +			break;
>   		if (buffer_uptodate(bh)) {
>   			brelse(bh);
>   			break;

Acked-by: Edward Shishkin <[email protected]>