[v2] fs/btrfs: Fix uninitialized variable
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Message ID 20210417153616.25056-1-khaledromdhani216@gmail.com
State New
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  • [v2] fs/btrfs: Fix uninitialized variable
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Commit Message

Khaled ROMDHANI April 17, 2021, 3:36 p.m. UTC
As reported by the Coverity static analysis.
The variable zone is not initialized which
may causes a failed assertion.

Addresses-Coverity: ("Uninitialized variables")
Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
---
v2: add a default case as proposed by David Sterba
---
 fs/btrfs/zoned.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

David Sterba April 19, 2021, 5:32 p.m. UTC | #1
On Sat, Apr 17, 2021 at 04:36:16PM +0100, Khaled ROMDHANI wrote:
> As reported by the Coverity static analysis.
> The variable zone is not initialized which
> may causes a failed assertion.
> 
> Addresses-Coverity: ("Uninitialized variables")
> Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> ---
> v2: add a default case as proposed by David Sterba
> ---
>  fs/btrfs/zoned.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index eeb3ebe11d7a..82527308d165 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -143,6 +143,9 @@ static inline u32 sb_zone_number(int shift, int mirror)
>  	case 0: zone = 0; break;
>  	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
>  	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
> +	default:
> +		zone = 0;

Well yeah but this is not a valid case at all, we'd rather catch that as
an assertion failure than letting is silently continue.
Dan Carpenter April 20, 2021, 10:22 a.m. UTC | #2
On Sat, Apr 17, 2021 at 04:36:16PM +0100, Khaled ROMDHANI wrote:
> As reported by the Coverity static analysis.
> The variable zone is not initialized which
> may causes a failed assertion.
> 
> Addresses-Coverity: ("Uninitialized variables")
> Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> ---
> v2: add a default case as proposed by David Sterba
> ---
>  fs/btrfs/zoned.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> index eeb3ebe11d7a..82527308d165 100644
> --- a/fs/btrfs/zoned.c
> +++ b/fs/btrfs/zoned.c
> @@ -143,6 +143,9 @@ static inline u32 sb_zone_number(int shift, int mirror)
>  	case 0: zone = 0; break;
>  	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
>  	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;

It took me a while to spot these break statements.

> +	default:
> +		zone = 0;
> +	break;

This break needs to be indented one more tab.

>  	}
>  
>  	ASSERT(zone <= U32_MAX);

regards,
dan carpenter
Khaled ROMDHANI April 20, 2021, 1:20 p.m. UTC | #3
On Mon, Apr 19, 2021 at 07:32:25PM +0200, David Sterba wrote:
> On Sat, Apr 17, 2021 at 04:36:16PM +0100, Khaled ROMDHANI wrote:
> > As reported by the Coverity static analysis.
> > The variable zone is not initialized which
> > may causes a failed assertion.
> > 
> > Addresses-Coverity: ("Uninitialized variables")
> > Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> > ---
> > v2: add a default case as proposed by David Sterba
> > ---
> >  fs/btrfs/zoned.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> > index eeb3ebe11d7a..82527308d165 100644
> > --- a/fs/btrfs/zoned.c
> > +++ b/fs/btrfs/zoned.c
> > @@ -143,6 +143,9 @@ static inline u32 sb_zone_number(int shift, int mirror)
> >  	case 0: zone = 0; break;
> >  	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
> >  	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
> > +	default:
> > +		zone = 0;
> 
> Well yeah but this is not a valid case at all, we'd rather catch that as
> an assertion failure than letting is silently continue.

So, as all callers pass valid value. It would be
better to catch that as an assertion failure.
Khaled ROMDHANI April 20, 2021, 1:39 p.m. UTC | #4
On Tue, Apr 20, 2021 at 01:22:14PM +0300, Dan Carpenter wrote:
> On Sat, Apr 17, 2021 at 04:36:16PM +0100, Khaled ROMDHANI wrote:
> > As reported by the Coverity static analysis.
> > The variable zone is not initialized which
> > may causes a failed assertion.
> > 
> > Addresses-Coverity: ("Uninitialized variables")
> > Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
> > ---
> > v2: add a default case as proposed by David Sterba
> > ---
> >  fs/btrfs/zoned.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
> > index eeb3ebe11d7a..82527308d165 100644
> > --- a/fs/btrfs/zoned.c
> > +++ b/fs/btrfs/zoned.c
> > @@ -143,6 +143,9 @@ static inline u32 sb_zone_number(int shift, int mirror)
> >  	case 0: zone = 0; break;
> >  	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
> >  	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
> 
> It took me a while to spot these break statements.
> 
> > +	default:
> > +		zone = 0;
> > +	break;
> 
> This break needs to be indented one more tab.
> 
> >  	}
> >  
> >  	ASSERT(zone <= U32_MAX);
> 
> regards,
> dan carpenter

Sorry, but I checked the patch using checkpatch.pl
before sending it. Is that blocks some smatch parsing process?

In any cases, I will send a V3.

Thanks.

Patch
diff mbox series

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index eeb3ebe11d7a..82527308d165 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -143,6 +143,9 @@  static inline u32 sb_zone_number(int shift, int mirror)
 	case 0: zone = 0; break;
 	case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
 	case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
+	default:
+		zone = 0;
+	break;
 	}
 
 	ASSERT(zone <= U32_MAX);