Re: [PATCH] fs/9p/xattr.c: avoid format-overflow warning

From: Su Hui
Date: Tue Oct 10 2023 - 04:20:05 EST



On 2023/10/10 15:51, Dan Carpenter wrote:
On Sun, Oct 08, 2023 at 02:01:39PM +0800, Su Hui wrote:
with gcc and W=1 option, there's a warning like this:

In file included from fs/9p/xattr.c:12:
In function ‘v9fs_xattr_get’,
inlined from ‘v9fs_listxattr’ at fs/9p/xattr.c:142:9:
include/net/9p/9p.h:55:2: error: ‘%s’ directive argument is null
[-Werror=format-overflow=]
55 | _p9_debug(level, __func__, fmt, ##__VA_ARGS__)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

use "" replace NULL to silence this warning.

Signed-off-by: Su Hui <suhui@xxxxxxxxxxxx>
---
fs/9p/xattr.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
index e00cf8109b3f..d995ee080835 100644
--- a/fs/9p/xattr.c
+++ b/fs/9p/xattr.c
@@ -139,7 +139,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
{
- return v9fs_xattr_get(dentry, NULL, buffer, buffer_size);
+ return v9fs_xattr_get(dentry, "", buffer, buffer_size);
I'm pretty uncomfortable with this patch... This code is 13 years old
so it can't be too huge of a problem. We're doing this for the printks,
but now they're going to look weird first of all.

Old: "file = (null)"
New: "file = "
Agreed, this looks  really weird and the patch is just for avoiding gcc's warning.
Sorry for the noise.

Su Hui


But also this must have some other effects on runtime right?

regards,
dan carpenter