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

From: Pavel Skripkin
Date: Mon Sep 27 2021 - 08:12:50 EST

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@xxxxxxxxx>
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:

Thank you!

Hi, Andrew,

Maybe this one can go through your tree?

With regards,
Pavel Skripkin