[Wayland-bugs] [Bug 108038] Xwayland crashes constantly (xorg-server-1.20.1 tag of xserver)

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Bug ID: 108038
Summary: Xwayland crashes constantly (xorg-server-1.20.1 tag of
xserver)
Product: Wayland
Version: unspecified
Hardware: x86-64 (AMD64)
OS: Linux (All)
Status: NEW
Severity: critical
Priority: medium
Component: XWayland
Assignee: wayland-***@lists.freedesktop.org
Reporter: ***@gmail.com
QA Contact: xorg-***@lists.x.org

Created attachment 141708
--> https://bugs.freedesktop.org/attachment.cgi?id=141708&action=edit
xwayland core dump from coredumpctl, can be used inside gdb

archlinux distro, gnome as desktop environment, gdm as desktop manager.

Rollback to xorg-server-1.20.0 fixes the issue.


There's core file attached.

Coredump info:

```plain
PID: 771 (Xwayland)
UID: 1000 (nartes)
GID: 1000 (nartes)
Signal: 6 (ABRT)
Timestamp: Sun 2018-09-23 17:04:52 +03 (56min ago)
Command Line: /usr/bin/Xwayland :0 -rootless -terminate -accessx -core
-listen 4 -listen 5 -displayfd 6
Executable: /usr/bin/Xwayland
Control Group: /user.slice/user-1000.slice/session-2.scope
Unit: session-2.scope
Slice: user-1000.slice
Session: 2
Owner UID: 1000 (nartes)
Boot ID: 4ad1bc740df242c2b7e786fccd484039
Machine ID: ec8ac8cf4cb14010ac2f461877ef63ac
Hostname: siarhei_hp
Storage:
/var/lib/systemd/coredump/core.Xwayland.1000.4ad1bc740df242c2b7e786fccd484039.771.1537711492000000.lz4
Message: Process 771 (Xwayland) of user 1000 dumped core.

Stack trace of thread 771:
#0 0x00007f168a998d7f raise (libc.so.6)
#1 0x00007f168a983672 abort (libc.so.6)
#2 0x0000562ff139e05a n/a (Xwayland)
#3 0x0000562ff1396425 n/a (Xwayland)
#4 0x0000562ff14bd3ec n/a (Xwayland)
#5 0x00007f168a273e8a n/a (libwayland-client.so.0)
#6 0x00007f168a26f1f9 n/a (libwayland-client.so.0)
#7 0x00007f1688d781c8 ffi_call_unix64 (libffi.so.6)
#8 0x00007f1688d77c2a ffi_call (libffi.so.6)
#9 0x00007f168a272f5f n/a (libwayland-client.so.0)
#10 0x00007f168a26f6ca n/a (libwayland-client.so.0)
#11 0x00007f168a270bdf wl_display_dispatch_queue_pending
(libwayland-client.so.0)
#12 0x0000562ff14bebdb n/a (Xwayland)
#13 0x0000562ff139fdd1 n/a (Xwayland)
#14 0x0000562ff1467ad0 n/a (Xwayland)
#15 0x0000562ff136210d n/a (Xwayland)
#16 0x00007f168a985223 __libc_start_main (libc.so.6)
#17 0x0000562ff136313e n/a (Xwayland)

Stack trace of thread 781:
#0 0x00007f1689672afc pthread_cond_wait@@GLIBC_2.3.2
(libpthread.so.0)
#1 0x00007f168655bf3c n/a (i965_dri.so)
#2 0x00007f168655bc78 n/a (i965_dri.so)
#3 0x00007f168966ca9d start_thread (libpthread.so.0)
#4 0x00007f168aa5ca43 __clone (libc.so.6)

Stack trace of thread 783:
#0 0x00007f1689672afc pthread_cond_wait@@GLIBC_2.3.2
(libpthread.so.0)
#1 0x00007f1684936054 n/a (swrast_dri.so)
#2 0x00007f1684935f98 n/a (swrast_dri.so)
#3 0x00007f168966ca9d start_thread (libpthread.so.0)
#4 0x00007f168aa5ca43 __clone (libc.so.6)

Stack trace of thread 782:
#0 0x00007f1689672afc pthread_cond_wait@@GLIBC_2.3.2
(libpthread.so.0)
#1 0x00007f1684936054 n/a (swrast_dri.so)
#2 0x00007f1684935f98 n/a (swrast_dri.so)
#3 0x00007f168966ca9d start_thread (libpthread.so.0)
#4 0x00007f168aa5ca43 __clone (libc.so.6)

PID: 789 (Xwayland)
UID: 1000 (nartes)
GID: 1000 (nartes)

```

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #1 from Olivier Fourdan <***@xfce.org> ---
Unfortunately, the core file (attachment 141708) is pretty useless without the
symbols.

Could you please provide a backtrace of the crash with the debugging symbols
attached instead?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #2 from Siarhei <***@gmail.com> ---
Yes, it is without them. Cause archlinux doesn't add "-g", pretty standard
pratice.
I have compiled upstream code, but yet didn't check whether it works.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #3 from Siarhei <***@gmail.com> ---
The problem seems to be an invalid display_handle, or authentication error.
Just guessing from a stacktrace.

In practice I reproduce the problem in the following way.
A new gnome-session is started, which runs Xwayland.
Then I switch a tty terminal.
And during this time an autostart execute skype process.
Which crashes Xwayland finally.
So it's some a problem within gnome, skype, or etc.

I've cross checked xorg-server-1.20.0, ..., xorg-server.1.20.1, as well as
master branch.
The problem is present at all of them.

```plain
(gdb) where
#0 0x00007fcfe9b25d7f in raise () from /usr/lib/libc.so.6
#1 0x00007fcfe9b10672 in abort () from /usr/lib/libc.so.6
#2 0x00005582a92a2fea in OsAbort () at ../xserver/os/utils.c:1350
#3 0x00005582a929b3e5 in AbortServer () at ../xserver/os/log.c:877
#4 FatalError (f=<optimized out>) at ../xserver/os/log.c:1015
#5 0x00005582a93c1e7c in xwl_log_handler (format=<optimized out>,
args=<optimized out>) at ../xserver/hw/xwayland/xwayland.c:1147
#6 0x00007fcfe91e8cb8 in wl_log (fmt=0x7fcfe91e9102 "%s@%u: error %d: %s\n")
at src/wayland-util.c:404
#7 0x00007fcfe91e3289 in display_handle_error (data=0x5582a9e268f0,
display=0x5582a9e268f0, object=0x5582a9e2cc00, code=0,
message=0x5582aa3c1af4 "authenicate failed") at src/wayland-client.c:898
#8 0x00007fcfe7ce11c8 in ffi_call_unix64 () from /usr/lib/libffi.so.6
#9 0x00007fcfe7ce0c2a in ffi_call () from /usr/lib/libffi.so.6
#10 0x00007fcfe91e7160 in wl_closure_invoke (closure=0x5582aa3c1a10, flags=1,
target=0x5582a9e268f0, opcode=0, data=0x5582a9e268f0) at src/connection.c:1006
#11 0x00007fcfe91e417f in dispatch_event (display=0x5582a9e268f0,
queue=0x5582a9e269a0) at src/wayland-client.c:1427
#12 0x00007fcfe91e443e in dispatch_queue (display=0x5582a9e268f0,
queue=0x5582a9e269b8) at src/wayland-client.c:1566
#13 0x00007fcfe91e4766 in wl_display_dispatch_queue_pending
(display=0x5582a9e268f0, queue=0x5582a9e269b8) at src/wayland-client.c:1815
#14 0x00007fcfe91e47d1 in wl_display_dispatch_pending (display=0x5582a9e268f0)
at src/wayland-client.c:1878
#15 0x00005582a93c360b in xwl_read_events (xwl_screen=<optimized out>,
xwl_screen=<optimized out>) at ../xserver/hw/xwayland/xwayland.c:820
#16 0x00005582a92a4d21 in ospoll_wait (ospoll=0x5582a9e1abe0,
timeout=<optimized out>) at ../xserver/os/ospoll.c:651
#17 0x00005582a936c850 in WaitForSomething (are_ready=0) at
../xserver/os/WaitFor.c:207
#18 Dispatch () at ../xserver/dix/dispatch.c:421
#19 0x00005582a9266ced in dix_main (envp=<optimized out>, argv=<optimized out>,
argc=<optimized out>) at ../xserver/dix/main.c:276
#20 main (argc=<optimized out>, argv=<optimized out>, envp=<optimized out>) at
../xserver/dix/stubmain.c:34

```

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Siarhei <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Summary|Xwayland crashes constantly |Xwayland crashes,
|(xorg-server-1.20.1 tag of |display_handle_error,
|xserver) |authenticate error inside
| |libwayland-client.so, GUI
| |app autostart whilst being
| |switched to TTY

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #4 from Olivier Fourdan <***@xfce.org> ---
That "authenicate failed" (with the typo in "authenicate") is typical of drm
authentication in Mesa:

175 static void
176 drm_authenticate(struct wl_client *client,
177 struct wl_resource *resource, uint32_t id)
178 {
179 struct wl_drm *drm = wl_resource_get_user_data(resource);
180
181 if (drm->callbacks.authenticate(drm->user_data, id) < 0)
182 wl_resource_post_error(resource,
183 WL_DRM_ERROR_AUTHENTICATE_FAIL,
184 "authenicate failed");
185 else
186 wl_resource_post_event(resource, WL_DRM_AUTHENTICATED);
187 }


https://cgit.freedesktop.org/mesa/mesa/tree/src/egl/wayland/wayland-drm/wayland-drm.c#n175

Does the issue occurs if you wait for the X client to start before switching to
another tty?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #5 from Siarhei <***@gmail.com> ---
Nope, it only happens when the session has been started. But there's some
application being spawned, whilst active screen is TTY with no graphics. And
the Xwayland operates at another TTY screen.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #6 from Siarhei <***@gmail.com> ---
What library provides drm_authenticate method?
I can recompile that one with debug symbols and set a breakpoint.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #7 from Siarhei <***@gmail.com> ---
(In reply to Siarhei from comment #0)

Post by b***@freedesktop.org
Rollback to xorg-server-1.20.0 fixes the issue.

Well, apparently it doesn't.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #8 from Olivier Fourdan <***@xfce.org> ---
Yeah, I think this is neither a regression nor a bug actually, by switching VT
while Xwayland is starting, you hinder drm auth and Xwayland can't start.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Siarhei <***@gmail.com> changed:

What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |NOTABUG
Status|NEW |RESOLVED

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #9 from Pekka Paalanen <***@gmail.com> ---
In the era of render nodes, why does Xwayland still need to use DRM auth?
Wouldn't that be a valid feature request, to avoid DRM auth?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #10 from Olivier Fourdan <***@xfce.org> ---
(In reply to Pekka Paalanen from comment #9)

Post by b***@freedesktop.org
In the era of render nodes, why does Xwayland still need to use DRM auth?
Wouldn't that be a valid feature request, to avoid DRM auth?

Actually, it does:

https://gitlab.freedesktop.org/xorg/xserver/blob/master/hw/xwayland/xwayland-glamor-gbm.c#L550

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #11 from Pekka Paalanen <***@gmail.com> ---
Ok, so it's actually related to the problem that wl_drm is still be only way
for a client to know which device the compositor is using.

Why wouldn't Xwayland look at the device and open the corresponding render node
instead if there is one? Maybe the drmDevice API in libdrm would make that easy
and portable nowadays?

Do we have an issue filed anywhere for making a companion extension to
zwp_linux_dmabuf so that clients can find out which device their buffers should
at least work on?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #12 from Olivier Fourdan <***@xfce.org> ---
(In reply to Pekka Paalanen from comment #11)

Post by b***@freedesktop.org
Ok, so it's actually related to the problem that wl_drm is still be only way
for a client to know which device the compositor is using.
Why wouldn't Xwayland look at the device and open the corresponding render
node instead if there is one? Maybe the drmDevice API in libdrm would make
that easy and portable nowadays?

Yeap, I reckon it should work, I can give that a try.

Post by b***@freedesktop.org
Do we have an issue filed anywhere for making a companion extension to
zwp_linux_dmabuf so that clients can find out which device their buffers
should at least work on?

Not to my recollection, but maybe ask Daniel or Jonas?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Post by b***@freedesktop.org
Do we have an issue filed anywhere for making a companion extension to
zwp_linux_dmabuf so that clients can find out which device their buffers
should at least work on?

Afraid not, but doing so would allow us to kill wl_drm completely. I wrote one
quickly though: https://gitlab.freedesktop.org/wayland/wayland/issues/5

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #14 from Daniel Stone <***@fooishbar.org> ---
(In reply to Daniel Stone from comment #13)

one quickly though: https://gitlab.freedesktop.org/wayland/wayland/issues/5

That should be https://gitlab.freedesktop.org/wayland/wayland/issues/59

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #15 from Pekka Paalanen <***@gmail.com> ---
https://gitlab.freedesktop.org/xorg/xserver/merge_requests/26 is proposing a
workaround.

ofourdan, should this be re-opened, or?

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Olivier Fourdan <***@xfce.org> changed:

What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|NOTABUG |---

--- Comment #16 from Olivier Fourdan <***@xfce.org> ---
(In reply to Pekka Paalanen from comment #15)

Post by b***@freedesktop.org
https://gitlab.freedesktop.org/xorg/xserver/merge_requests/26 is proposing a
workaround.
ofourdan, should this be re-opened, or?

Sure, we can reopen.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

Olivier Fourdan <***@xfce.org> changed:

What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|REOPENED |RESOLVED

--- Comment #17 from Olivier Fourdan <***@xfce.org> ---
Patch has landed in git master, re-closing.

[b***@freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=108038

--- Comment #18 from Siarhei <***@gmail.com> ---
I've tested the upstream build.
There's no issue with a crash now.
But Xwayland session doesn't process keyboard nor mouse events anymore.
Looks like it's been detached from that session, or the device is not
considered a real seat in terms of loginctl.