On 9/30/20 10:58 AM, Christian Borntraeger wrote: > gcc 10 from Fedora 32 gives me: > > Compiling C object libblock.fa.p/nbd_server.c.o > ../nbd/server.c: In function ‘nbd_co_client_start’: > ../nbd/server.c:625:14: error: ‘namelen’ may be used uninitialized in this > function [-Werror=maybe-uninitialized] > 625 | rc = nbd_negotiate_send_info(client, NBD_INFO_NAME, namelen, > name, > | > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 626 | errp); > | ~~~~~ > ../nbd/server.c:564:14: note: ‘namelen’ was declared here > 564 | uint32_t namelen; > | ^~~~~~~ > cc1: all warnings being treated as errors > > As I cannot see how this can happen, let uns silence the warning.
gcc is smart enough to see that nbd_opt_read_name(... &namelen), which is the only use of namelen between declaration and use, does not always initialize namelen; but fails to see we also exit this function early in the same conditions when nbd_opt_read_name left namelen uninit. The workaround is fine. Reviewed-by: Eric Blake <ebl...@redhat.com> I'm happy for this to go in through the trivial tree, but I'll also queue it on my NBD tree if that is ready first. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org
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