[PATCH] sysv: use BUILD_BUG_ON instead of runtime check

[PATCH] sysv: use BUILD_BUG_ON instead of runtime check

[Pavel Skripkin]

There was runtime checks about sizes of struct v7_super_block
and struct sysv_inode. If one of these checks fail kernel will panic.
Since these values are known on complite time let's use BUILD_BUG_ON(),
because it's standard mechanism for validation checking at build time

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
---
 fs/sysv/super.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/fs/sysv/super.c b/fs/sysv/super.c
index cc8e2ed155c8..d1def0771a40 100644
--- a/fs/sysv/super.c
+++ b/fs/sysv/super.c
@@ -474,10 +474,8 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
 	struct sysv_sb_info *sbi;
 	struct buffer_head *bh;
 
-	if (440 != sizeof (struct v7_super_block))
-		panic("V7 FS: bad super-block size");
-	if (64 != sizeof (struct sysv_inode))
-		panic("sysv fs: bad i-node size");
+	BUILD_BUG_ON(sizeof(struct v7_super_block) != 440);
+	BUILD_BUG_ON(sizeof(struct sysv_inode) != 64);
 
 	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
 	if (!sbi)
-- 
2.32.0

Re: [PATCH] sysv: use BUILD_BUG_ON instead of runtime check

[Pavel Skripkin]

On 8/13/21 15:30, Pavel Skripkin wrote:
> There was runtime checks about sizes of struct v7_super_block
> and struct sysv_inode. If one of these checks fail kernel will panic.
> Since these values are known on complite time let's use BUILD_BUG_ON(),
> because it's standard mechanism for validation checking at build time
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
> ---
>   fs/sysv/super.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/sysv/super.c b/fs/sysv/super.c
> index cc8e2ed155c8..d1def0771a40 100644
> --- a/fs/sysv/super.c
> +++ b/fs/sysv/super.c
> @@ -474,10 +474,8 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
>   	struct sysv_sb_info *sbi;
>   	struct buffer_head *bh;
>   
> -	if (440 != sizeof (struct v7_super_block))
> -		panic("V7 FS: bad super-block size");
> -	if (64 != sizeof (struct sysv_inode))
> -		panic("sysv fs: bad i-node size");
> +	BUILD_BUG_ON(sizeof(struct v7_super_block) != 440);
> +	BUILD_BUG_ON(sizeof(struct sysv_inode) != 64);
>   
>   	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
>   	if (!sbi)
> 

Hi, David and Alexander!


Maybe, this one can go through one of your trees? I didn't find any sysv 
related trees, so..

Lore link to the patch: 
https://lore.kernel.org/lkml/20210813123020.22971-1-paskripkin@gmail.com/



Thank you!


With regards,
Pavel Skripkin

Re: [PATCH] sysv: use BUILD_BUG_ON instead of runtime check

[Pavel Skripkin]

On 9/1/21 13:15, Pavel Skripkin wrote:
> On 8/13/21 15:30, Pavel Skripkin wrote:
>> There was runtime checks about sizes of struct v7_super_block
>> and struct sysv_inode. If one of these checks fail kernel will panic.
>> Since these values are known on complite time let's use BUILD_BUG_ON(),
>> because it's standard mechanism for validation checking at build time
>> 
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
>> Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
>> ---
>>   fs/sysv/super.c | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>> 
>> diff --git a/fs/sysv/super.c b/fs/sysv/super.c
>> index cc8e2ed155c8..d1def0771a40 100644
>> --- a/fs/sysv/super.c
>> +++ b/fs/sysv/super.c
>> @@ -474,10 +474,8 @@ static int v7_fill_super(struct super_block *sb, void *data, int silent)
>>   	struct sysv_sb_info *sbi;
>>   	struct buffer_head *bh;
>>   
>> -	if (440 != sizeof (struct v7_super_block))
>> -		panic("V7 FS: bad super-block size");
>> -	if (64 != sizeof (struct sysv_inode))
>> -		panic("sysv fs: bad i-node size");
>> +	BUILD_BUG_ON(sizeof(struct v7_super_block) != 440);
>> +	BUILD_BUG_ON(sizeof(struct sysv_inode) != 64);
>>   
>>   	sbi = kzalloc(sizeof(struct sysv_sb_info), GFP_KERNEL);
>>   	if (!sbi)
>> 
> 
> Hi, David and Alexander!
> 
> 
> Maybe, this one can go through one of your trees? I didn't find any sysv
> related trees, so..
> 
> Lore link to the patch:
> https://lore.kernel.org/lkml/20210813123020.22971-1-paskripkin@gmail.com/
> 
> 
> 
> Thank you!


Hi, Andrew,

Maybe this one can go through your tree?



With regards,
Pavel Skripkin