Re: [Qemu-devel] [PULL 00/20] Migration pull requset

[Dr. David Alan Gilbert]

* Cornelia Huck (address@hidden) wrote:
> On Fri, 24 Aug 2018 18:05:03 +0100
> Peter Maydell <address@hidden> wrote:
> 
> > On 22 August 2018 at 13:00, Juan Quintela <address@hidden> wrote:
> > > The following changes since commit 
> > > 13b7b188501d419a7d63c016e00065bcc693b7d4:
> > >
> > >   Merge remote-tracking branch 
> > > 'remotes/kraxel/tags/vga-20180821-pull-request' into staging (2018-08-21 
> > > 15:57:56 +0100)
> > >
> > > are available in the Git repository at:
> > >
> > >   git://github.com/juanquintela/qemu.git tags/migration/20180822-1
> > >
> > > for you to fetch changes up to ae526e32bd36cfb84045c8d2fd34e0b9e39a52f8:
> > >
> > >   migration: hold the lock only if it is really needed (2018-08-22 
> > > 12:36:18 +0200)
> > >
> > > ----------------------------------------------------------------
> > > migration/next for 20180822
> > >
> > > All pending patches that are reviewed:
> > > - doc for pr_load (dave)
> > > - postcopy + rdma is nearer (lidong chen)
> > > - compression fixes (xiao)
> > > - silent warning for pcc tests (Thomas)
> > > - fix subsection without .needed function (pmaydell)
> > >
> > > Please apply, Juan.
> > >
> > > ----------------------------------------------------------------  
> > 
> > Applied, thanks.
> > 
> > -- PMM
> > 
> 
> The rdma migration code in there seems to upset my clang (5.0.2, Fedora
> 27); gcc (7.3.1) does not complain.
> 
> /home/cohuck/git/qemu/migration/rdma.c:4035:9: error: variable
>       'rdma_return_path' is used uninitialized whenever 'if' condition is true
>       [-Werror,-Wsometimes-uninitialized]
>     if (ret) {
>         ^~~
> /home/cohuck/git/qemu/migration/rdma.c:4059:12: note: uninitialized use occurs
>       here
>     g_free(rdma_return_path);
>            ^~~~~~~~~~~~~~~~

Yes, it's got a point.
While the 'rdma' and 'rdma_return_path' are now more symmetry after 55cc1b5937a
the rdma_return_path needs NULL initialisation because the rdma variable
is set very early, where as the return path isn't set until much later.

Dave

> /home/cohuck/git/qemu/migration/rdma.c:4035:5: note: remove the 'if' if its
>       condition is always false
>     if (ret) {
>     ^~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4027:9: error: variable
>       'rdma_return_path' is used uninitialized whenever 'if' condition is true
>       [-Werror,-Wsometimes-uninitialized]
>     if (ret) {
>         ^~~
> /home/cohuck/git/qemu/migration/rdma.c:4059:12: note: uninitialized use occurs
>       here
>     g_free(rdma_return_path);
>            ^~~~~~~~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4027:5: note: remove the 'if' if its
>       condition is always false
>     if (ret) {
>     ^~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4021:9: error: variable
>       'rdma_return_path' is used uninitialized whenever 'if' condition is true
>       [-Werror,-Wsometimes-uninitialized]
>     if (rdma == NULL) {
>         ^~~~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4059:12: note: uninitialized use occurs
>       here
>     g_free(rdma_return_path);
>            ^~~~~~~~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4021:5: note: remove the 'if' if its
>       condition is always false
>     if (rdma == NULL) {
>     ^~~~~~~~~~~~~~~~~~~
> /home/cohuck/git/qemu/migration/rdma.c:4015:41: note: initialize the variable
>       'rdma_return_path' to silence this warning
>     RDMAContext *rdma, *rdma_return_path;
>                                         ^
>                                          = NULL
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK