Mesa (master): nv50: fix crash in nv50_pre_pipebuffer_map (nv50_screen-> cur_ctx)

[Ben Skeggs]

Module: Mesa
Branch: master
Commit: 0ef781c1ae04451ac4f184187e900f872cad5f94
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0ef781c1ae04451ac4f184187e900f872cad5f94

Author: Marcin Slusarz <marcin.slusarz at gmail.com>
Date:   Wed Jan 20 23:27:07 2010 +0100

nv50: fix crash in nv50_pre_pipebuffer_map (nv50_screen->cur_ctx)

nv50_pre_pipebuffer_map references screen->cur_ctx which points
to freed memory after the context is destroyed.
This crash is easily triggerable by progs/xdemos/glxcontexts.

---

 src/gallium/drivers/nv50/nv50_context.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/src/gallium/drivers/nv50/nv50_context.c b/src/gallium/drivers/nv50/nv50_context.c
index e2198b1..5c705cc 100644
--- a/src/gallium/drivers/nv50/nv50_context.c
+++ b/src/gallium/drivers/nv50/nv50_context.c
@@ -86,6 +86,10 @@ nv50_destroy(struct pipe_context *pipe)
 		so_ref(NULL, &nv50->state.vtxattr);
 
 	draw_destroy(nv50->draw);
+
+	if (nv50->screen->cur_ctx == nv50)
+		nv50->screen->cur_ctx = NULL;
+
 	FREE(nv50);
 }