| Message ID | 201610050807.AA00000@WIN-5MHF4RKU941.jp.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, Oct 05, 2016 at 05:07:48PM +0900, Tsutomu Itoh wrote: > In v4.8-rc1, gcc 5.3.1 gives following warning. Fixed it. > > [CC] btrfs-image.o > btrfs-image.c: In function 'flush_pending': > btrfs-image.c:708:17: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized] > header->bytenr = cpu_to_le64(start); > ^ > btrfs-image.c:927:6: note: 'start' was declared here > u64 start; > ^ So the patch makes the compiler warning go away, but is the code correct? AFAICS, the warning points to the case where flush_pending is called with done=1 (from create_metadump) and there's zero md->pending_size . Are you sure this is an expected state and that the function can proceed with state = 0 ? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2016/10/07 1:00, David Sterba wrote: > On Wed, Oct 05, 2016 at 05:07:48PM +0900, Tsutomu Itoh wrote: >> In v4.8-rc1, gcc 5.3.1 gives following warning. Fixed it. >> >> [CC] btrfs-image.o >> btrfs-image.c: In function 'flush_pending': >> btrfs-image.c:708:17: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized] >> header->bytenr = cpu_to_le64(start); >> ^ >> btrfs-image.c:927:6: note: 'start' was declared here >> u64 start; >> ^ > > So the patch makes the compiler warning go away, but is the code > correct? AFAICS, the warning points to the case where flush_pending is > called with done=1 (from create_metadump) and there's zero > md->pending_size . Are you sure this is an expected state and that the > function can proceed with state = 0 ? > I think that this is a case where some errors occurred before calling flush_pending. Therefore, create_metadump returns the error to the caller. (creating the image fails, I think.) Thanks, Tsutomu -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/btrfs-image.c b/btrfs-image.c index 0d410f8..47f36b9 100644 --- a/btrfs-image.c +++ b/btrfs-image.c @@ -924,7 +924,7 @@ static int flush_pending(struct metadump_struct *md, int done) struct async_work *async = NULL; struct extent_buffer *eb; u64 blocksize = md->root->nodesize; - u64 start; + u64 start = 0; u64 size; size_t offset; int ret = 0;
In v4.8-rc1, gcc 5.3.1 gives following warning. Fixed it. [CC] btrfs-image.o btrfs-image.c: In function 'flush_pending': btrfs-image.c:708:17: warning: 'start' may be used uninitialized in this function [-Wmaybe-uninitialized] header->bytenr = cpu_to_le64(start); ^ btrfs-image.c:927:6: note: 'start' was declared here u64 start; ^ Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com> --- btrfs-image.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)