xserver-multidpi/hw/xwayland
Olivier Fourdan 4cbf1fb1f9 xwayland: Avoid double free of RRCrtc and RROutput
At shutdown, the Xserver will free all its resources which includes the
RRCrtc and RROutput created.

Xwayland would do the same in its xwl_output_destroy() called from
xwl_close_screen(), leading to a double free of existing RRCrtc
RROutput:

 Invalid read of size 4
    at 0x4CDA10: RRCrtcDestroy (rrcrtc.c:689)
    by 0x426E75: xwl_output_destroy (xwayland-output.c:301)
    by 0x424144: xwl_close_screen (xwayland.c:117)
    by 0x460E17: CursorCloseScreen (cursor.c:187)
    by 0x4EB5A3: AnimCurCloseScreen (animcur.c:106)
    by 0x4EF431: present_close_screen (present_screen.c:64)
    by 0x556D40: dix_main (main.c:354)
    by 0x6F0D290: (below main) (in /usr/lib/libc-2.24.so)
  Address 0xbb1fc30 is 0 bytes inside a block of size 728 free'd
    at 0x4C2BDB0: free (in
/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    by 0x4CCE5F: RRCrtcDestroyResource (rrcrtc.c:719)
    by 0x577541: doFreeResource (resource.c:895)
    by 0x5787B5: FreeClientResources (resource.c:1161)
    by 0x578862: FreeAllResources (resource.c:1176)
    by 0x556C54: dix_main (main.c:323)
    by 0x6F0D290: (below main) (in /usr/lib/libc-2.24.so)
  Block was alloc'd at
    at 0x4C2CA6A: calloc (in
/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
    by 0x4CC6DB: RRCrtcCreate (rrcrtc.c:76)
    by 0x426D1C: xwl_output_create (xwayland-output.c:264)
    by 0x4232EC: registry_global (xwayland.c:431)
    by 0x76CB1C7: ffi_call_unix64 (in /usr/lib/libffi.so.6.0.4)
    by 0x76CAC29: ffi_call (in /usr/lib/libffi.so.6.0.4)
    by 0x556CEFD: wl_closure_invoke (connection.c:935)
    by 0x5569CBF: dispatch_event.isra.4 (wayland-client.c:1310)
    by 0x556AF13: dispatch_queue (wayland-client.c:1456)
    by 0x556AF13: wl_display_dispatch_queue_pending
(wayland-client.c:1698)
    by 0x556B33A: wl_display_roundtrip_queue (wayland-client.c:1121)
    by 0x42371C: xwl_screen_init (xwayland.c:631)
    by 0x552F60: AddScreen (dispatch.c:3864)

And:

 Invalid read of size 4
    at 0x522890: RROutputDestroy (rroutput.c:348)
    by 0x42684E: xwl_output_destroy (xwayland-output.c:302)
    by 0x423CF4: xwl_close_screen (xwayland.c:118)
    by 0x4B6377: CursorCloseScreen (cursor.c:187)
    by 0x539503: AnimCurCloseScreen (animcur.c:106)
    by 0x53D081: present_close_screen (present_screen.c:64)
    by 0x43DBF0: dix_main (main.c:354)
    by 0x7068730: (below main) (libc-start.c:289)
  Address 0xc403190 is 0 bytes inside a block of size 154 free'd
    at 0x4C2CD5A: free (vg_replace_malloc.c:530)
    by 0x521DF3: RROutputDestroyResource (rroutput.c:389)
    by 0x45DA61: doFreeResource (resource.c:895)
    by 0x45ECFD: FreeClientResources (resource.c:1161)
    by 0x45EDC2: FreeAllResources (resource.c:1176)
    by 0x43DB04: dix_main (main.c:323)
    by 0x7068730: (below main) (libc-start.c:289)
  Block was alloc'd at
    at 0x4C2BBAD: malloc (vg_replace_malloc.c:299)
    by 0x52206B: RROutputCreate (rroutput.c:84)
    by 0x426763: xwl_output_create (xwayland-output.c:270)
    by 0x422EDC: registry_global (xwayland.c:432)
    by 0x740FC57: ffi_call_unix64 (unix64.S:76)
    by 0x740F6B9: ffi_call (ffi64.c:525)
    by 0x5495A9D: wl_closure_invoke (connection.c:949)
    by 0x549283F: dispatch_event.isra.4 (wayland-client.c:1274)
    by 0x5493A13: dispatch_queue (wayland-client.c:1420)
    by 0x5493A13: wl_display_dispatch_queue_pending
(wayland-client.c:1662)
    by 0x5493D2E: wl_display_roundtrip_queue (wayland-client.c:1085)
    by 0x4232EC: xwl_screen_init (xwayland.c:632)
    by 0x439F50: AddScreen (dispatch.c:3864)

Split xwl_output_destroy() into xwl_output_destroy() which frees the
wl_output and the xwl_output structure, and xwl_output_remove() which
does the RRCrtcDestroy() and RROutputDestroy() and call the latter only
when an output is effectively removed.

An additional benefit, on top of avoiding a double free, is to avoid
updating the screen size at shutdown.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
2016-08-15 14:20:54 -04:00
..
.gitignore Xwayland DDX 2014-04-03 15:19:22 -07:00
drm.xml xwayland: Add glamor and DRI3 support 2014-06-24 15:09:55 -07:00
Makefile.am xwayland: add glamor Xv adaptor 2016-03-09 14:03:03 -05:00
xwayland-cursor.c xwayland: Plug memleak in frame callbacks 2016-08-15 12:49:36 -04:00
xwayland-cvt.c xwayland: do not include frequency in mode name 2016-03-28 14:09:09 -04:00
xwayland-glamor-xv.c xwayland: Fix compiler warning in GLAMOR Xv 2016-04-15 16:22:16 -04:00
xwayland-glamor.c xwayland: Fix whitespace errors 2016-06-20 15:40:07 +10:00
xwayland-input.c xwayland-input: Fake crossing to rootwin 2016-06-23 16:00:30 +10:00
xwayland-output.c xwayland: Avoid double free of RRCrtc and RROutput 2016-08-15 14:20:54 -04:00
xwayland-shm.c xwayland-shm: fortify fallocate against EINTR 2016-04-25 15:29:40 -04:00
xwayland-vidmode.c xwayland: Pretend we support viewport in vidmode 2016-03-28 14:10:59 -04:00
xwayland.c xwayland: Avoid double free of RRCrtc and RROutput 2016-08-15 14:20:54 -04:00
xwayland.h xwayland: Avoid double free of RRCrtc and RROutput 2016-08-15 14:20:54 -04:00