On Thu, Jul 20, 2017 at 06:04:44PM +0100, Dr. David Alan Gilbert wrote: > * Daniel P. Berrange (berra...@redhat.com) wrote: > > On Thu, Jul 20, 2017 at 05:15:49PM +0100, Dr. David Alan Gilbert wrote: > > > * Daniel P. Berrange (berra...@redhat.com) wrote: > > > > On Fri, Apr 07, 2017 at 03:38:47PM +0100, Dr. David Alan Gilbert wrote: > > > > > Hi, > > > > > Fedora 26 has gcc 7.0.1 which has the normal compliment > > > > > of new fussy warnings; so far I've posted : > > > > > > > > > > tests/check-qdict: Fix missing brackets > > > > > slirp/smb: Replace constant strings by glib string > > > > > > > > > > that fix one actual mistake and work around something it's being > > > > > fussy over. > > > > > > > > > > But I've also got a pile of hacks, attached below that I'm > > > > > not too sure what I'll do with them yet, but they're attached > > > > > for anyone else trying to build. Note they're smoke-only-tested. > > > > > > > > > > I also have gcc bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80346 > > > > > filed for what I reckon is a couple of overly pessimistic warnings. > > > > > > > > > > > > > diff --git a/include/qemu/iov.h b/include/qemu/iov.h > > > > > index bd9fd55b0a..ebb0221140 100644 > > > > > --- a/include/qemu/iov.h > > > > > +++ b/include/qemu/iov.h > > > > > @@ -46,7 +46,7 @@ static inline size_t > > > > > iov_from_buf(const struct iovec *iov, unsigned int iov_cnt, > > > > > size_t offset, const void *buf, size_t bytes) > > > > > { > > > > > - if (__builtin_constant_p(bytes) && iov_cnt && > > > > > + if (__builtin_constant_p(bytes) && iov_cnt && bytes <= INT_MAX && > > > > > offset <= iov[0].iov_len && bytes <= iov[0].iov_len - > > > > > offset) { > > > > > memcpy(iov[0].iov_base + offset, buf, bytes); > > > > > return bytes; > > > > > @@ -59,7 +59,7 @@ static inline size_t > > > > > iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt, > > > > > size_t offset, void *buf, size_t bytes) > > > > > { > > > > > - if (__builtin_constant_p(bytes) && iov_cnt && > > > > > + if (__builtin_constant_p(bytes) && iov_cnt && bytes <= INT_MAX && > > > > > offset <= iov[0].iov_len && bytes <= iov[0].iov_len - > > > > > offset) { > > > > > memcpy(buf, iov[0].iov_base + offset, bytes); > > > > > return bytes; > > > > > > tbh I don't know what the right fix for this is; the gcc discussion > > > confused me as to why it thinks it can be a valid case. > > > > Even if gcc is broken in issuing a warning here, we still need to > > make it quiet so people on F26 and similarly new distros can build > > without warnings. > > I agree. > > > IMHO your patch is ok, or we could be alittle more explicit about > > catching just the case where you pass -1 for bytes, and have > > > > && bytes != -1 > > This seems bizarre to me since bytes is size_t bytes and size_t > is unsigned, so I'd have sympathy for a compiler that warned that > bytes != -1 was always true.
Could be paranoid and do "&& bytes != (size_t)-1" Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
