[PATCH weston v2 00/16] Tablet device support for weston

Tue Nov 28 08:48:00 UTC 2017

Hi Jason,

Thanks for testing and sharing the backtraces. I will go through the logs and try to find out the root cause.

Best regards,

Devadoss Maniraj
RBEI/ECF3  

Tel. +91 80 6136-4382 

-----Original Message-----
From: Jason Gerecke [mailto:killertofu at gmail.com] 
Sent: Tuesday, November 28, 2017 3:27 AM
To: Maniraj Devadoss (RBEI/ECF3) <Maniraj.Devadoss at in.bosch.com>
Cc: wayland-devel at lists.freedesktop.org
Subject: Re: [PATCH weston v2 00/16] Tablet device support for weston

On Thu, Nov 23, 2017 at 2:17 AM, Maniraj Devadoss <Maniraj.Devadoss at in.bosch.com> wrote:
> Hi,
>
> The previous posting of this series was at 
> https://lists.freedesktop.org/archives/wayland-devel/2017-October/0355
> 34.html
>
> which had some issues when Jason Gerecke <killertofu at gmail.com> tried to test it.
> https://lists.freedesktop.org/archives/wayland-devel/2017-November/035
> 716.html
>
> In this v2 series, I resolved one possible NULL pointer access issue 
> in input.c
>
> Best Regards,
> Maniraj D.
>

Thanks for the updated patches, Maniraj. I'm still running into a crash when the pen is brought into proximity for a second time, this time with the following backtrace (full coredump available on
request):

#0  0x00007f0dffda7b6f in surface_stash_subsurface_views
(surface=0x55e380cc1930) at libweston/compositor.c:2141
#1  0x00007f0dffdac626 in weston_compositor_build_view_list
(compositor=compositor at entry=0x55e380b49400) at
libweston/compositor.c:2252
#2  0x00007f0dffdacb1e in weston_output_repaint (output=0x55e380d040e0,
repaint_data=repaint_data at entry=0x55e380d27da0) at
libweston/compositor.c:2308
#3  0x00007f0dffdaeeb7 in weston_output_maybe_repaint (output=output at entry=0x55e380d040e0, now=now at entry=0x7fff9627cde0,
repaint_data=repaint_data at entry=0x55e380d27da0) at
libweston/compositor.c:2408
#4  0x00007f0dffdaef51 in output_repaint_timer_handler
(data=0x55e380b49400) at libweston/compositor.c:2474
#5  0x00007f0dffb8f2ca in  () at /usr/lib/libwayland-server.so.0
#6  0x00007f0dffb8f9b2 in wl_event_loop_dispatch () at
/usr/lib/libwayland-server.so.0
#7  0x00007f0dffb8e14c in wl_display_run () at /usr/lib/libwayland-server.so.0
#8  0x000055e37eaacb64 in main (argc=<optimized out>,
argv=0x7fff9627d3a8) at compositor/main.c:1970

GDB states that it "Cannot access memory at address 0x454341465245540e" when trying to print the value of "sub->surface"
from frame 0. Because of this, I tried recompiling with "-fsanitize=address" and consistently got the following error when bringing the pen into proximity for a second time (full log attached):

==12921==ERROR: AddressSanitizer: heap-use-after-free on address
0x616000052b80 at pc 0x7f02c7fdb6fa bp 0x7ffd10383910 sp
0x7ffd10383900
READ of size 8 at 0x616000052b80 thread T0
    #0 0x7f02c7fdb6f9 in weston_compositor_build_view_list
libweston/compositor.c:2252
    #1 0x7f02c7fdc15f in weston_output_repaint libweston/compositor.c:2308
    #2 0x7f02c7fe17e3 in weston_output_maybe_repaint libweston/compositor.c:2408
    #3 0x7f02c7fe19a7 in output_repaint_timer_handler
libweston/compositor.c:2474
    #4 0x7f02c7da52c9  (/usr/lib/libwayland-server.so.0+0x92c9)
    #5 0x7f02c7da59b1 in wl_event_loop_dispatch
(/usr/lib/libwayland-server.so.0+0x99b1)
    #6 0x7f02c7da414b in wl_display_run (/usr/lib/libwayland-server.so.0+0x814b)
    #7 0x5563675582dd in main compositor/main.c:1970
    #8 0x7f02c6b7cf69 in __libc_start_main (/usr/lib/libc.so.6+0x20f69)
    #9 0x55636754da99 in _start (/usr/local/bin/weston+0x9a99)

0x616000052b80 is located 0 bytes inside of 576-byte region
[0x616000052b80,0x616000052dc0)
freed by thread T0 here:
    #0 0x7f02c8314711 in __interceptor_free
/build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:45
    #1 0x7f02c7fdba56 in weston_view_destroy libweston/compositor.c:1872
    #2 0x7f02c7fe4fcf in tablet_tool_unmap_sprite libweston/input.c:1524
    #3 0x7f02c7fe636f in tablet_tool_set_cursor libweston/input.c:2823
    #4 0x7f02c5f951c7 in ffi_call_unix64 (/usr/lib/libffi.so.6+0x61c7)

previously allocated by thread T0 here:
    #0 0x7f02c8314ce1 in __interceptor_calloc
/build/gcc/src/gcc/libsanitizer/asan/asan_malloc_linux.cc:70
    #1 0x7f02c7fd16b4 in zalloc shared/zalloc.h:38
    #2 0x7f02c7fd16b4 in weston_view_create libweston/compositor.c:270
    #3 0x7f02c7fe63f9 in tablet_tool_set_cursor libweston/input.c:2832
    #4 0x7f02c5f951c7 in ffi_call_unix64 (/usr/lib/libffi.so.6+0x61c7)

I also notice that the "default_grab_tablet_tool_proximity_out"
function has a comment indicating that it should be trying to hide the cursor, but I don't see the pen cursor disappearing when the pen leaves prox. Perhaps it is related?

Jason
---
Now instead of four in the eights place / you’ve got three, ‘Cause you added one  /
(That is to say, eight) to the two,     /
But you can’t take seven from three,    /
So you look at the sixty-fours....

> Bastian Farkas (3):
>   tablet: Fixed compilation errors resulting from tablet patches.
>   tablet: Fixing compilation issues in weston desktop-shell related to
>     tablet support patches.
>   tablet: reordered changes in weston_seat struct to not break ABI
>     compatibility
>
> Lyude Paul (13):
>   tablet: Add initial tablet support to weston
>   tablet: add handling of tablet focus
>   tablet: add weston grab interfaces for tablet tools
>   tablet: hook up libinput tablet events
>   tablet: handle tablet cursors in the compositor
>   clients: add support for handling tablets
>   client: Add tablet cursor support into libtoytoolkit
>   client: Add support for tablet cursor motion to window frames in
>     libtoytoolkit
>   tablet: Add support for moving windows around using the stylus
>   tablet: Add tablet support to the top panel of the desktop shell
>   tablet: Add binding to activate surfaces using the tablet tool
>   tablet: Add demo application for tablets
>   tablet: Remove tablet-specific tools on disconnect
>
>  .gitignore                  |   1 +
>  Makefile.am                 |  20 +-
>  clients/desktop-shell.c     |  56 +++
>  clients/tablet.c            | 254 ++++++++++++
>  clients/window.c            | 686 +++++++++++++++++++++++++++++++
>  clients/window.h            |  93 +++++
>  configure.ac                |   2 +-
>  desktop-shell/shell.c       | 289 +++++++++++++
>  libweston/bindings.c        |  39 +-
>  libweston/compositor.c      |   8 +
>  libweston/compositor.h      | 204 ++++++++++
>  libweston/input.c           | 963 ++++++++++++++++++++++++++++++++++++++++++++
>  libweston/libinput-device.c | 340 ++++++++++++++++
>  libweston/libinput-device.h |   4 +-
>  shared/cairo-util.h         |   4 +
>  shared/frame.c              |  38 ++
>  16 files changed, 2994 insertions(+), 7 deletions(-)  create mode 
> 100644 clients/tablet.c
>
> --
> 2.7.4
>
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