| Message ID | 20190903033019.GA149622@LGEARND20B15 (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: fix Wmaybe-uninitialized warning | expand |
Hello, maintainers. If you are available, please review this patch and share the feedback. Thanks, Austin Kim 2019년 9월 3일 (화) 오후 12:30, Austin Kim <austindh.kim@gmail.com>님이 작성: > > gcc throws warning message as below: > > ‘clone_src_i_size’ may be used uninitialized in this function > [-Wmaybe-uninitialized] > #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) > ^ > fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here > u64 clone_src_i_size; > ^ > The clone_src_i_size is only used as call-by-reference > in a call to get_inode_info(). > > Silence the warning by initializing clone_src_i_size to 0. > > Signed-off-by: Austin Kim <austindh.kim@gmail.com> > --- > fs/btrfs/send.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c > index f856d6c..197536b 100644 > --- a/fs/btrfs/send.c > +++ b/fs/btrfs/send.c > @@ -5085,7 +5085,7 @@ static int clone_range(struct send_ctx *sctx, > struct btrfs_path *path; > struct btrfs_key key; > int ret; > - u64 clone_src_i_size; > + u64 clone_src_i_size = 0; > > /* > * Prevent cloning from a zero offset with a length matching the sector > -- > 2.6.2 >
On Tue, Sep 03, 2019 at 12:30:19PM +0900, Austin Kim wrote: > gcc throws warning message as below: What version of gcc reports that? 9.2.1 does not. > ‘clone_src_i_size’ may be used uninitialized in this function > [-Wmaybe-uninitialized] > #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) > ^ > fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here > u64 clone_src_i_size; > ^ > The clone_src_i_size is only used as call-by-reference > in a call to get_inode_info(). The reference is passed to a static function, so the compiler has enough information to determine if it's unused. By inspection I don't see a problem with the uninitalized variable: if __get_inode_info succeeds, there's a valid value, in error case it's not used at all.
On Tue, Sep 03, 2019 at 12:30:19PM +0900, Austin Kim wrote: > gcc throws warning message as below: > > ‘clone_src_i_size’ may be used uninitialized in this function > [-Wmaybe-uninitialized] > #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) > ^ > fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here > u64 clone_src_i_size; > ^ > The clone_src_i_size is only used as call-by-reference > in a call to get_inode_info(). > > Silence the warning by initializing clone_src_i_size to 0. > > Signed-off-by: Austin Kim <austindh.kim@gmail.com> A few more people have repoted this warning, so I'm gonig to apply the patch to avoid further reports. Thanks.
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index f856d6c..197536b 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -5085,7 +5085,7 @@ static int clone_range(struct send_ctx *sctx, struct btrfs_path *path; struct btrfs_key key; int ret; - u64 clone_src_i_size; + u64 clone_src_i_size = 0; /* * Prevent cloning from a zero offset with a length matching the sector
gcc throws warning message as below: ‘clone_src_i_size’ may be used uninitialized in this function [-Wmaybe-uninitialized] #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) ^ fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here u64 clone_src_i_size; ^ The clone_src_i_size is only used as call-by-reference in a call to get_inode_info(). Silence the warning by initializing clone_src_i_size to 0. Signed-off-by: Austin Kim <austindh.kim@gmail.com> --- fs/btrfs/send.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)