27.02.2015 10:50, [email protected] wrote:
> From: Gonglei <[email protected]>
>
> Signed-off-by: Gonglei <[email protected]>
> ---
> hw/9pfs/virtio-9p-local.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
> index a183eee..bcad4e0 100644
> --- a/hw/9pfs/virtio-9p-local.c
> +++ b/hw/9pfs/virtio-9p-local.c
> @@ -500,7 +500,6 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath
> *dir_path,
> buffer = rpath(fs_ctx, path);
> err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
> if (err == -1) {
> - g_free(buffer);
> goto out;
> }
> err = local_set_xattr(buffer, credp);
> @@ -513,7 +512,6 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath
> *dir_path,
> buffer = rpath(fs_ctx, path);
> err = mknod(buffer, SM_LOCAL_MODE_BITS|S_IFREG, 0);
> if (err == -1) {
> - g_free(buffer);
> goto out;
> }
> err = local_set_mapped_file_attr(fs_ctx, path, credp);
> @@ -526,7 +524,6 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath
> *dir_path,
> buffer = rpath(fs_ctx, path);
> err = mknod(buffer, credp->fc_mode, credp->fc_rdev);
> if (err == -1) {
> - g_free(buffer);
> goto out;
> }
> err = local_post_create_passthrough(fs_ctx, path, credp);
> @@ -540,8 +537,8 @@ static int local_mknod(FsContext *fs_ctx, V9fsPath
> *dir_path,
> err_end:
> remove(buffer);
> errno = serrno;
> - g_free(buffer);
> out:
> + g_free(buffer);
> v9fs_string_free(&fullname);
> return err;
> }
> @@ -676,7 +673,6 @@ static int local_open2(FsContext *fs_ctx, V9fsPath
> *dir_path, const char *name,
> buffer = rpath(fs_ctx, path);
> fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
> if (fd == -1) {
> - g_free(buffer);
> err = fd;
> goto out;
> }
> @@ -691,7 +687,6 @@ static int local_open2(FsContext *fs_ctx, V9fsPath
> *dir_path, const char *name,
> buffer = rpath(fs_ctx, path);
> fd = open(buffer, flags, SM_LOCAL_MODE_BITS);
> if (fd == -1) {
> - g_free(buffer);
> err = fd;
> goto out;
> }
> @@ -707,7 +702,6 @@ static int local_open2(FsContext *fs_ctx, V9fsPath
> *dir_path, const char *name,
> buffer = rpath(fs_ctx, path);
> fd = open(buffer, flags, credp->fc_mode);
> if (fd == -1) {
> - g_free(buffer);
> err = fd;
> goto out;
> }
> @@ -725,8 +719,8 @@ err_end:
> close(fd);
> remove(buffer);
> errno = serrno;
> - g_free(buffer);
> out:
> + g_free(buffer);
> v9fs_string_free(&fullname);
> return err;
> }
This patch introduces a compiler warning, which is technically
correct:
hw/9pfs/virtio-9p-local.c: In function ‘local_open2’:
hw/9pfs/virtio-9p-local.c:723:5: error: ‘buffer’ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
g_free(buffer);
^
hw/9pfs/virtio-9p-local.c: In function ‘local_mknod’:
hw/9pfs/virtio-9p-local.c:541:5: error: ‘buffer’ may be used uninitialized in
this function [-Werror=maybe-uninitialized]
g_free(buffer);
^
This is because `buffer' variable is initialized within one
of the `if' branches but is left uninitialized if none of
the conditions is true. In reality this can't happen because
at least one condition is always true.
It is a one more reason to rewrite this code like I mentioned
in another mail instead of trying to fix random issues like
this. I'll try to come up with a patch doing that shortly.
Meanwhile I'll drop this patch.
Thanks,
/mjt
