[PATCH] btrfs: Fix uninitialized ret in btrfsic_process_superblock_dev_mirror

[PATCH] btrfs: Fix uninitialized ret in btrfsic_process_superblock_dev_mirror

[Nikolay Borisov]

We could return ret uninitlaized in case of success. Before the code was
returning 0 explicitly in case of success but now it will be a random value from
the stack. That's due to ret being set only in error conditions.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/check-integrity.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 23dd65e1c5e3..85b27e9742c8 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -766,7 +766,7 @@ static int btrfsic_process_superblock_dev_mirror(
 	struct block_device *const superblock_bdev = device->bdev;
 	struct page *page;
 	struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
-	int ret;
+	int ret = 0;

 	/* super block bytenr is always the unmapped device bytenr */
 	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
--
2.17.1

Re: [PATCH] btrfs: Fix uninitialized ret in btrfsic_process_superblock_dev_mirror

[Nikolay Borisov]

On 24.02.20 г. 14:56 ч., Nikolay Borisov wrote:
> We could return ret uninitlaized in case of success. Before the code was
> returning 0 explicitly in case of success but now it will be a random value from
> the stack. That's due to ret being set only in error conditions.
> 
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>

This ideally has to be folded in:
5a03d907a555 ("btrfs: remove buffer_heads form super block mirror
integrity checking")

> ---
>  fs/btrfs/check-integrity.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
> index 23dd65e1c5e3..85b27e9742c8 100644
> --- a/fs/btrfs/check-integrity.c
> +++ b/fs/btrfs/check-integrity.c
> @@ -766,7 +766,7 @@ static int btrfsic_process_superblock_dev_mirror(
>  	struct block_device *const superblock_bdev = device->bdev;
>  	struct page *page;
>  	struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
> -	int ret;
> +	int ret = 0;
> 
>  	/* super block bytenr is always the unmapped device bytenr */
>  	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
> --
> 2.17.1
> 

Re: [PATCH] btrfs: Fix uninitialized ret in btrfsic_process_superblock_dev_mirror

[Qu Wenruo]

On 2020/2/24 下午8:56, Nikolay Borisov wrote:
> We could return ret uninitlaized in case of success. Before the code was
> returning 0 explicitly in case of success but now it will be a random value from
> the stack. That's due to ret being set only in error conditions.
>
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>  fs/btrfs/check-integrity.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
> index 23dd65e1c5e3..85b27e9742c8 100644
> --- a/fs/btrfs/check-integrity.c
> +++ b/fs/btrfs/check-integrity.c
> @@ -766,7 +766,7 @@ static int btrfsic_process_superblock_dev_mirror(
>  	struct block_device *const superblock_bdev = device->bdev;
>  	struct page *page;
>  	struct address_space *mapping = superblock_bdev->bd_inode->i_mapping;
> -	int ret;
> +	int ret = 0;
>
>  	/* super block bytenr is always the unmapped device bytenr */
>  	dev_bytenr = btrfs_sb_offset(superblock_mirror_num);
> --
> 2.17.1
>

Re: [PATCH] btrfs: Fix uninitialized ret in btrfsic_process_superblock_dev_mirror

[David Sterba]

On Mon, Feb 24, 2020 at 02:57:00PM +0200, Nikolay Borisov wrote:
> 
> 
> On 24.02.20 г. 14:56 ч., Nikolay Borisov wrote:
> > We could return ret uninitlaized in case of success. Before the code was
> > returning 0 explicitly in case of success but now it will be a random value from
> > the stack. That's due to ret being set only in error conditions.
> > 
> > Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> 
> This ideally has to be folded in:
> 5a03d907a555 ("btrfs: remove buffer_heads form super block mirror
> integrity checking")

Folded and pushed, thanks.