andreacavalli/xserver-multidpi
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

xwayland: Avoid double free of RRCrtc and RROutput

Browse Source 
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>
This commit is contained in:
Olivier Fourdan 2016-08-08 17:57:57 +02:00 committed by Adam Jackson
parent b380f3ac51
commit 4cbf1fb1f9
3 changed files with 12 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
hw/xwayland/xwayland-output.c
View File

@ -291,21 +291,27 @@ err:
void
xwl_output_destroy(struct xwl_output *xwl_output)
{
wl_output_destroy(xwl_output->output);
free(xwl_output);
}
void
xwl_output_remove(struct xwl_output *xwl_output)
{
struct xwl_output *it;
struct xwl_screen *xwl_screen = xwl_output->xwl_screen;
int width = 0, height = 0;
wl_output_destroy(xwl_output->output);
xorg_list_del(&xwl_output->link);
RRCrtcDestroy(xwl_output->randr_crtc);
RROutputDestroy(xwl_output->randr_output);
xorg_list_del(&xwl_output->link);
xorg_list_for_each_entry(it, &xwl_screen->output_list, link)
output_get_new_size(it, &height, &width);
update_screen_size(xwl_output, width, height);
free(xwl_output);
xwl_output_destroy(xwl_output);
}
static Bool

2
hw/xwayland/xwayland.c
View File

@ -453,7 +453,7 @@ global_remove(void *data, struct wl_registry *registry, uint32_t name)
xorg_list_for_each_entry_safe(xwl_output, tmp_xwl_output,
&xwl_screen->output_list, link) {
if (xwl_output->server_output_id == name) {
xwl_output_destroy(xwl_output);
xwl_output_remove(xwl_output);
break;
}
}

2
hw/xwayland/xwayland.h
View File

@ -174,6 +174,8 @@ struct xwl_output *xwl_output_create(struct xwl_screen *xwl_screen,
void xwl_output_destroy(struct xwl_output *xwl_output);
void xwl_output_remove(struct xwl_output *xwl_output);
RRModePtr xwayland_cvt(int HDisplay, int VDisplay,
float VRefresh, Bool Reduced, Bool Interlaced);