diff --git a/pkgs/development/libraries/mesa/default.nix b/pkgs/development/libraries/mesa/default.nix
index 59e68c60de96..31b284c3cc49 100644
--- a/pkgs/development/libraries/mesa/default.nix
+++ b/pkgs/development/libraries/mesa/default.nix
@@ -150,6 +150,7 @@ stdenv.mkDerivation {
 
   patches = [
     ./opencl.patch
+    ./musl.patch
   ];
 
   postPatch = ''
diff --git a/pkgs/development/libraries/mesa/musl.patch b/pkgs/development/libraries/mesa/musl.patch
new file mode 100644
index 000000000000..07f6c9c41463
--- /dev/null
+++ b/pkgs/development/libraries/mesa/musl.patch
@@ -0,0 +1,39 @@
+From 571dedac8881649cd94c59488413b835cbcf0498 Mon Sep 17 00:00:00 2001
+From: Alyssa Ross <hi@alyssa.is>
+Date: Thu, 20 Nov 2025 23:16:47 +0100
+Subject: [PATCH] rocket: fix building for musl
+
+musl follows POSIX and provides ioctl as int ioctl(int, int, ...).
+
+Fixes: 5b829658f74 ("rocket: Initial commit of a driver for Rockchip's NPU")
+Signed-off-by: Alyssa Ross <hi@alyssa.is>
+Link: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38561
+---
+ src/gallium/drivers/rocket/intercept.c | 10 ++++++++--
+ 1 file changed, 8 insertions(+), 2 deletions(-)
+
+diff --git a/src/gallium/drivers/rocket/intercept.c b/src/gallium/drivers/rocket/intercept.c
+index 6ffb8647d61f5..88e55893d9520 100644
+--- a/src/gallium/drivers/rocket/intercept.c
++++ b/src/gallium/drivers/rocket/intercept.c
+@@ -294,9 +294,15 @@ handle_action(struct rknpu_action *args)
+    }
+ }
+ 
+-typedef int (*real_ioctl_t)(int fd, unsigned long request, ...);
++#ifdef __GLIBC__
++typedef unsigned long ioctl_req;
++#else
++typedef int ioctl_req; // per POSIX
++#endif
++
++typedef int (*real_ioctl_t)(int fd, ioctl_req request, ...);
+ int
+-ioctl(int fd, unsigned long request, ...)
++ioctl(int fd, ioctl_req request, ...)
+ {
+    int ret;
+    uint32_t output_address = 0;
+-- 
+GitLab
+