xserver: Branch 'master'

Adam Jackson ajax at kemper.freedesktop.org
Mon Aug 15 19:12:15 UTC 2016


 hw/xwayland/xwayland-output.c |   12 +++++++++---
 hw/xwayland/xwayland.c        |    2 +-
 hw/xwayland/xwayland.h        |    2 ++
 3 files changed, 12 insertions(+), 4 deletions(-)

New commits:
commit 4cbf1fb1f978ecd975770cebbb330dc10f712b77
Author: Olivier Fourdan <ofourdan at redhat.com>
Date:   Mon Aug 8 17:57:57 2016 +0200

    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 at redhat.com>
    Reviewed-by: Hans de Goede <hdegoede at redhat.com>

diff --git a/hw/xwayland/xwayland-output.c b/hw/xwayland/xwayland-output.c
index 39b93dc..ef3b6f6 100644
--- a/hw/xwayland/xwayland-output.c
+++ b/hw/xwayland/xwayland-output.c
@@ -292,20 +292,26 @@ 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
diff --git a/hw/xwayland/xwayland.c b/hw/xwayland/xwayland.c
index 97d998e..a41b619 100644
--- a/hw/xwayland/xwayland.c
+++ b/hw/xwayland/xwayland.c
@@ -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;
         }
     }
diff --git a/hw/xwayland/xwayland.h b/hw/xwayland/xwayland.h
index aaaa431..8db8df5 100644
--- a/hw/xwayland/xwayland.h
+++ b/hw/xwayland/xwayland.h
@@ -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);
 


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