From ad06c12c89791dad0c3858a75102277127158063 Mon Sep 17 00:00:00 2001 From: Steven Newbury Date: Tue, 8 Feb 2022 12:02:51 +0000 Subject: util: Fix infinite loop in recursive function When testing Xwayland multi-HiDPI support with Wine + SimCity4 I encountered a 100% CPU lockup from sway. This turned out to be triggering a bug in the wlroots pointer contraint code. region_confine() contains multiple recursive calls where arguments are modified and resubmitted to the function. One of the calls is however made using the original arguments, if/when this triggers it results in the same codepath being followed each loop so the condition always applies. It makes much more sense if this was intended to apply the clamped values x,y instead of the original x1,y1, and indeed this fixes the infinite loop and results in correct behaviour. --- util/region.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'util') diff --git a/util/region.c b/util/region.c index 817d7b1a..c5bd9e85 100644 --- a/util/region.c +++ b/util/region.c @@ -214,7 +214,7 @@ static void region_confine(pixman_region32_t *region, double x1, double y1, doub int y_ext = floor(y) + (dy == 0 ? 0 : dy > 0 ? 1 : -1); if (pixman_region32_contains_point(region, x_ext, y_ext, &box)) { - return region_confine(region, x1, y1, x2, y2, x2_out, y2_out, box); + return region_confine(region, x, y, x2, y2, x2_out, y2_out, box); } else if (dx == 0 || dy == 0) { *x2_out = x; *y2_out = y; -- cgit v1.2.3