On Mon, 22 Apr 2024 at 19:40, Bernd Schubert <bernd.schubert@xxxxxxxxxxx> wrote:
>
> The test for NULL was done for the member of union fuse_file_args,
> but not for fuse_file_args itself.
>
> Fixes: e26ee4efbc796 ("fuse: allocate ff->release_args only if release is needed")
> Signed-off-by: Bernd Schubert <bschubert@xxxxxxx>
>
> ---
> I'm currently going through all the recent patches again and noticed
> in code review. I guess this falls through testing, because we don't
> run xfstests that have !fc->no_opendir || !fc->no_open.
>
> Note: Untested except that it compiles.
>
> Note2: Our IT just broke sendmail, I'm quickly sending through thunderbird,
> I hope doesn't change the patch format.
>
> fs/fuse/file.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index b57ce4157640..0ff865457ea6 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -102,7 +102,8 @@ static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args,
> static void fuse_file_put(struct fuse_file *ff, bool sync)
> {
> if (refcount_dec_and_test(&ff->count)) {
> - struct fuse_release_args *ra = &ff->args->release_args;
> + struct fuse_release_args *ra =
> + ff->args ? &ff->args->release_args : NULL;
While this looks like a NULL pointer dereference, it isn't, because
&foo->bar is just pointer arithmetic, and in this case the pointers
will be identical. So it will work, but the whole ff->args thing is a
bit confusing. Not sure how to properly clean this up, your patch
seems to be just adding more obfuscation.
Thanks,
Miklos
