From d97688b6b3b709c3c2aefd99ad3fa0a399ba914c Mon Sep 17 00:00:00 2001
From: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Date: Wed, 25 Mar 2026 15:28:42 +0100
Subject: [PATCH] drm-shim: fix shim on GLX
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xcb_dri3_open_reply_fds will dup the fd received from the server,
so we need to detect this case.

Reviewed-by: Emma Anholt <emma@anholt.net>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40656>
---
 src/drm-shim/drm_shim.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/drm-shim/drm_shim.c b/src/drm-shim/drm_shim.c
index 4547aa1ca27..789c05f3d93 100644
--- a/src/drm-shim/drm_shim.c
+++ b/src/drm-shim/drm_shim.c
@@ -805,8 +805,19 @@ fcntl(int fd, int cmd, ...)
 
    int ret = real_fcntl(fd, cmd, arg);
 
-   if (shim_fd && (cmd == F_DUPFD || cmd == F_DUPFD_CLOEXEC))
-      drm_shim_fd_register(ret, shim_fd);
+   if (cmd == F_DUPFD || cmd == F_DUPFD_CLOEXEC) {
+      if (shim_fd) {
+         drm_shim_fd_register(ret, shim_fd);
+      } else {
+         /* x11_dri3_open / xcb_dri3_open_reply_fds will end up here. */
+         drmVersionPtr ver = drmGetVersion(fd);
+         if (ver) {
+            drm_shim_fd_register(fd, NULL);
+            drm_shim_fd_register(ret, drm_shim_fd_lookup(fd));
+            drmFree(ver);
+         }
+      }
+   }
 
    return ret;
 }