Mesa (master): egl/dri2: fix race between image create and egl_image_target_texture

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Module: Mesa
Branch: master
Commit: 959c2d1edbf56934f6d313a48136f6f1740dc549
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=959c2d1edbf56934f6d313a48136f6f1740dc549

Author: Tapani Pälli <tapani.palli at intel.com>
Date:   Tue Nov 10 15:52:00 2020 +0200

egl/dri2: fix race between image create and egl_image_target_texture

All other functions calling _eglLookupImage hold the display lock.

 ==16659== Possible data race during write of size 8 at 0x5D1BCF0 by thread #2668
 ==16659== Locks held: 1, at address 0x5D1B6F8
 ==16659==    at 0x5405DDF: _eglLinkResource (egldisplay.c:454)
 ==16659==    by 0x53F9189: _eglLinkImage (eglimage.h:138)
 ==16659==    by 0x53FE2CA: _eglCreateImageCommon (eglapi.c:1740)
 ==16659==    by 0x53FE39A: eglCreateImageKHR (eglapi.c:1751)
 ==16659==
 ==16659== This conflicts with a previous read of size 8 by thread #2664
 ==16659== Locks held: 1, at address 0x5308D00
 ==16659==    at 0x5405C06: _eglCheckResource (egldisplay.c:387)
 ==16659==    by 0x5408C92: _eglLookupImage (eglimage.h:162)
 ==16659==    by 0x5409E96: dri2_lookup_egl_image (egl_dri2.c:688)
 ==16659==    by 0x6210AAF: dri2_lookup_egl_image (dri_helpers.c:250)
 ==16659==    by 0x6212843: dri_get_egl_image (dri_screen.c:470)
 ==16659==    by 0x625F7CC: st_get_egl_image (st_cb_eglimage.c:152)
 ==16659==    by 0x625FE7D: st_egl_image_target_texture_2d (st_cb_eglimage.c:354)
 ==16659==    by 0x6501C05: egl_image_target_texture (teximage.c:3446)

Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Cc: mesa-stable
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7544>

---

 src/egl/drivers/dri2/egl_dri2.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index a4164cccb8e..337889781d2 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -690,7 +690,10 @@ dri2_lookup_egl_image(__DRIscreen *screen, void *image, void *data)
 
    (void) screen;
 
+   mtx_lock(&disp->Mutex);
    img = _eglLookupImage(image, disp);
+   mtx_unlock(&disp->Mutex);
+
    if (img == NULL) {
       _eglError(EGL_BAD_PARAMETER, "dri2_lookup_egl_image");
       return NULL;