diff options
author | Michel Dänzer <mdaenzer@redhat.com> | 2023-03-10 12:39:30 +0100 |
---|---|---|
committer | Michel Dänzer <michel@daenzer.net> | 2023-03-27 08:19:31 +0000 |
commit | 754d6b6dd0a9ec42d75247596a8885bf54352ee7 (patch) | |
tree | 9176de8b1c855380712c4a24e0c39cad980d40ab /hw/xwayland | |
parent | 4d1cd7cdc22013ed8de17d3218b9790b7027e1fe (diff) |
xwayland: Prevent nested xwl_present_for_each_frame_callback calls
It could happen with the following call path:
frame_callback
xwl_present_frame_callback
xwl_present_msc_bump
xwl_present_execute
xwl_present_flip
xwl_window_create_frame_callback
The nested loop called xwl_present_reset_timer, which may end up calling
xorg_list_del for the entry after the one frame_callback started the
chain for. This resulted in the outer loop never terminating, because
its next element wasn't hooked up to the list anymore.
We avoid this by calling xwl_present_reset_timer as needed in
frame_callback, and bailing from xwl_window_create_frame_callback if it
was called from the former.
We also catch nested calls and FatalError if they ever happen again due
to another bug.
v2:
* Leave xwl_present_reset_timer call in xwl_present_frame_callback,
needed if xwl_present_msc_bump didn't hook up the window to the frame
callback list again.
Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1442
Diffstat (limited to 'hw/xwayland')
-rw-r--r-- | hw/xwayland/xwayland-present.c | 15 | ||||
-rw-r--r-- | hw/xwayland/xwayland-present.h | 1 | ||||
-rw-r--r-- | hw/xwayland/xwayland-window.c | 16 |
3 files changed, 30 insertions, 2 deletions
diff --git a/hw/xwayland/xwayland-present.c b/hw/xwayland/xwayland-present.c index e8a173774..189e7cfd6 100644 --- a/hw/xwayland/xwayland-present.c +++ b/hw/xwayland/xwayland-present.c @@ -89,16 +89,31 @@ xwl_present_event_from_id(uint64_t event_id) return (struct xwl_present_event*)(uintptr_t)event_id; } +static Bool entered_for_each_frame_callback; + +Bool +xwl_present_entered_for_each_frame_callback(void) +{ + return entered_for_each_frame_callback; +} + void xwl_present_for_each_frame_callback(struct xwl_window *xwl_window, void iter_func(struct xwl_present_window *)) { struct xwl_present_window *xwl_present_window, *tmp; + if (entered_for_each_frame_callback) + FatalError("Nested xwl_present_for_each_frame_callback call"); + + entered_for_each_frame_callback = TRUE; + xorg_list_for_each_entry_safe(xwl_present_window, tmp, &xwl_window->frame_callback_list, frame_callback_list) iter_func(xwl_present_window); + + entered_for_each_frame_callback = FALSE; } static void diff --git a/hw/xwayland/xwayland-present.h b/hw/xwayland/xwayland-present.h index 620e6c5ca..806272089 100644 --- a/hw/xwayland/xwayland-present.h +++ b/hw/xwayland/xwayland-present.h @@ -61,6 +61,7 @@ struct xwl_present_event { PixmapPtr pixmap; }; +Bool xwl_present_entered_for_each_frame_callback(void); void xwl_present_for_each_frame_callback(struct xwl_window *xwl_window, void iter_func(struct xwl_present_window *)); void xwl_present_reset_timer(struct xwl_present_window *xwl_present_window); diff --git a/hw/xwayland/xwayland-window.c b/hw/xwayland/xwayland-window.c index b80a7bf67..6b7f38605 100644 --- a/hw/xwayland/xwayland-window.c +++ b/hw/xwayland/xwayland-window.c @@ -1226,8 +1226,16 @@ frame_callback(void *data, xwl_window->frame_callback = NULL; #ifdef GLAMOR_HAS_GBM - if (xwl_window->xwl_screen->present) + if (xwl_window->xwl_screen->present) { xwl_present_for_each_frame_callback(xwl_window, xwl_present_frame_callback); + + /* If xwl_window_create_frame_callback was called from + * xwl_present_frame_callback, need to make sure all fallback timers + * are adjusted correspondingly. + */ + if (xwl_window->frame_callback) + xwl_present_for_each_frame_callback(xwl_window, xwl_present_reset_timer); + } #endif } @@ -1243,7 +1251,11 @@ xwl_window_create_frame_callback(struct xwl_window *xwl_window) xwl_window); #ifdef GLAMOR_HAS_GBM - if (xwl_window->xwl_screen->present) + /* If we get called from frame_callback, it will take care of calling + * xwl_present_reset_timer. + */ + if (xwl_window->xwl_screen->present && + !xwl_present_entered_for_each_frame_callback()) xwl_present_for_each_frame_callback(xwl_window, xwl_present_reset_timer); #endif } |