On 2018/2月/23 08:53, Derek Foreman wrote:
> On 2018-02-23 07:44 AM, Markus Ongyerth wrote:
> > On 2018/2月/23 07:31, Derek Foreman wrote:
> > > On 2018-02-23 03:52 AM, w...@ongy.net wrote:
> > > > From: Markus Ongyerth <w...@ongy.net>
> > > > 
> > > > This is related to the discussion earlier on the mailing list and
> > > > demonstrates a problem with current wl_priv_signal_emit and wl_listener
> > > > that free themselves, but do not remove from the list.
> > > > 
> > > > This testcase asserts that the wl_list inside wl_listener is not written
> > > > to anymore after it got emitted.
> > > > ---
> > > >    Makefile.am                 |  3 +++
> > > >    tests/free-without-remove.c | 63 
> > > > +++++++++++++++++++++++++++++++++++++++++++++
> > > >    2 files changed, 66 insertions(+)
> > > >    create mode 100644 tests/free-without-remove.c
> > > > 
> > > > diff --git a/Makefile.am b/Makefile.am
> > > > index 322d6b8..c51f328 100644
> > > > --- a/Makefile.am
> > > > +++ b/Makefile.am
> > > > @@ -158,6 +158,7 @@ pkgconfig_DATA += egl/wayland-egl-backend.pc
> > > >    built_test_programs =                                \
> > > >         array-test                              \
> > > > +       free-without-remove-test                \
> > > >         client-test                             \
> > > >         display-test                            \
> > > >         connection-test                         \
> > > > @@ -223,6 +224,8 @@ libtest_runner_la_LIBADD =                  \
> > > >    array_test_SOURCES = tests/array-test.c
> > > >    array_test_LDADD = libtest-runner.la
> > > > +free_without_remove_test_SOURCES = tests/free-without-remove.c
> > > > +free_without_remove_test_LDADD = libtest-runner.la
> > > >    client_test_SOURCES = tests/client-test.c
> > > >    client_test_LDADD = libtest-runner.la
> > > >    display_test_SOURCES = tests/display-test.c
> > > > diff --git a/tests/free-without-remove.c b/tests/free-without-remove.c
> > > > new file mode 100644
> > > > index 0000000..ff468d7
> > > > --- /dev/null
> > > > +++ b/tests/free-without-remove.c
> > > > @@ -0,0 +1,63 @@
> > > > +/*
> > > > + * Copyright © 2018 Markus Ongyerth
> > > > + *
> > > > + * Permission is hereby granted, free of charge, to any person 
> > > > obtaining
> > > > + * a copy of this software and associated documentation files (the
> > > > + * "Software"), to deal in the Software without restriction, including
> > > > + * without limitation the rights to use, copy, modify, merge, publish,
> > > > + * distribute, sublicense, and/or sell copies of the Software, and to
> > > > + * permit persons to whom the Software is furnished to do so, subject 
> > > > to
> > > > + * the following conditions:
> > > > + *
> > > > + * The above copyright notice and this permission notice (including the
> > > > + * next paragraph) shall be included in all copies or substantial
> > > > + * portions of the Software.
> > > > + *
> > > > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> > > > + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
> > > > + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> > > > + * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
> > > > + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
> > > > + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
> > > > + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
> > > > + * SOFTWARE.
> > > > + */
> > > > +
> > > > +#include <stdio.h>
> > > > +#include <stdlib.h>
> > > > +#include <stdarg.h>
> > > > +#include <string.h>
> > > > +#include <assert.h>
> > > > +#include <sys/socket.h>
> > > > +#include <unistd.h>
> > > > +#include <errno.h>
> > > > +#include <sys/types.h>
> > > > +#include <sys/stat.h>
> > > > +
> > > > +#include "wayland-private.h"
> > > > +#include "wayland-server.h"
> > > > +#include "test-runner.h"
> > > > +
> > > > +static void
> > > > +display_destroy_notify(struct wl_listener *l, void *data)
> > > > +{
> > > > +       l->link.prev = l->link.next = NULL;
> > > > +}
> > > > +
> > > > +TEST(free_without_remove)
> > > > +{
> > > > +       struct wl_display *display;
> > > > +       struct wl_listener a, b;
> > > > +
> > > > +       display = wl_display_create();
> > > > +       a.notify = display_destroy_notify;
> > > > +       b.notify = display_destroy_notify;
> > > > +
> > > > +       wl_display_add_destroy_listener(display, &a);
> > > > +       wl_display_add_destroy_listener(display, &b);
> > > > +
> > > > +       wl_display_destroy(display);
> > > > +
> > > > +       assert(a.link.next == a.link.prev && a.link.next == NULL);
> > > > +       assert(b.link.next == b.link.prev && b.link.next == NULL);
> > > 
> > > I feel this would be slightly more clear if it tested
> > > a.link.next == NULL && a.link.prev == NULL
> > Possibly.
> > > 
> > > As my previously submit test did... is this significantly more rigorous 
> > > than
> > > my test here: https://patchwork.freedesktop.org/patch/206013/  ?
> > Did you try to run this one? It *fails* on the current version of 
> > libwayland,
> > because wl_priv_signal_emit will write into one of the wl_listeners after it
> > got emitted.
> > 
> > This only happens where there's more than one listener in the signal list,
> > which is the reason your test doesn't catch it.
> 
> More rigorous indeed - but we can't land it without fixing the bug first. :)
I agree. I just wanted to get this out since it shows an issue with the 
asumption destroy listeners are never touched and current wl_priv_signal.
(Because that partialy proves my point).
I would probably integrate a test like this, maybe even more thorough, in the 
patch series for the new signal handling that fixes it.
> 
> Also, I'm not sure it warrants a whole new file when it could just piggy
> back an existing test...  I guess now that I think about it, signal-test
> seems most appropriate?
Quite likely. I didn't expect this to be merged at the current time, and 
rather be subsumed into a patch series fixing the specific bug, so I didn't 
care too much to make it fit style guidelines or figure out where to place it.
> 
> Thanks,
> Derek
> 
> > > 
> > > Thanks,
> > > Derek
> > > 
> > > > +}
> > > > 
> > > 
> > > _______________________________________________
> > > wayland-devel mailing list
> > > wayland-devel@lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/wayland-devel
> 

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