Re: [Qemu-devel] [PULL 00/15] vhost, pc: fixes for 2.5

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Nov 26, 2015 at 06:19:46PM +0200, Michael S. Tsirkin wrote:
> On Thu, Nov 26, 2015 at 11:26:10AM +0000, Peter Maydell wrote:
> > On 19 November 2015 at 13:35, Michael S. Tsirkin <mst@redhat.com> wrote:
> > > The following changes since commit 8337c6cbc37c6b2184f41bab3eaff47d5e68012a:
> > >
> > >   Update version for v2.5.0-rc0 release (2015-11-13 17:10:36 +0000)
> > >
> > > are available in the git repository at:
> > >
> > >   git://git.kernel.org/pub/scm/virt/kvm/mst/qemu.git tags/for_upstream
> > >
> > > for you to fetch changes up to 1c7ba94a184df1eddd589d5400d879568d3e5d08:
> > >
> > >   exec: silence hugetlbfs warning under qtest (2015-11-19 15:26:05 +0200)
> > >
> > > ----------------------------------------------------------------
> > > vhost, pc: fixes for 2.5
> > >
> > > Fixes all over the place.
> > >
> > > This also re-enables a test we disabled in 2.5 cycle
> > > now that there's a way not to get a warning from it.
> > >
> > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > 
> > Hi; I've just noticed that since this pull was applied the Travis
> > builds have been failing:
> > https://travis-ci.org/qemu/qemu/builds
> > 
> > The log messages are rather odd but suggest a virtio-user problem:
> 
> So far, it looks like I found a bunch of qemu-char (or possibly glib?)
> problems.
> This is on Fedora 23.
> How to reproduce:
> 
> First, apply this patch:
> 
> 	vhost-user-test: fix migration overlap test
> 
> Now
> 
> [mst@robin qemu]$ make -j 16
>   CC    qemu-char.o
>   LINK  x86_64-softmmu/qemu-system-x86_64
>   LINK  i386-softmmu/qemu-system-i386
> [mst@robin qemu]$ make tests/vhost-user-test
>   CC    tests/vhost-user-test.o
>   LINK  tests/vhost-user-test
> 
> 
> Run under valgrind:
> 	QTEST_QEMU_BINARY=./x86_64-softmmu/qemu-system-x86_64 valgrind tests/vhost-user-test
> 
> What seems to happen is that after remove_fd_in_watch, read callback
> is still invoked. read fails so it calls close, and close
> causes use after free.
> 
> Help would be appreciated.

Here's the log:
http://paste.fedoraproject.org/294863/55491614

As you see tcp_chr_close freed a bunch of
stuff, and now tcp_chr_read attempts to use it.

> -- 
> MST