aya: Fix program loading on kernels with a patch > 255

aya/src/programs/mod.rs

@@ -617,14 +617,8 @@ fn load_program<T: Link>(
         },
     ) = obj;
 
-    let target_kernel_version = kernel_version.unwrap_or_else(|| {
-        let KernelVersion {
-            major,
-            minor,
-            patch,
-        } = KernelVersion::current().unwrap();
-        (u32::from(major) << 16) + (u32::from(minor) << 8) + u32::from(patch)
-    });
+    let target_kernel_version =
+        kernel_version.unwrap_or_else(|| KernelVersion::current().unwrap().code());
 
     let prog_name = if let Some(name) = name {
         let mut name = name.clone();

aya/src/util.rs

@@ -68,6 +68,20 @@ impl KernelVersion {
         kernel_version
     }
 
+    /// The equivalent of LINUX_VERSION_CODE
+    pub(crate) fn code(self) -> u32 {
+        let Self {
+            major,
+            minor,
+            patch,
+        } = self;
+        // clamp patch to 255 to avoid it overflowing into the minor version.
+        //
+        // See: https://github.com/torvalds/linux/commit/9b82f13e7ef316cdc0a8858f1349f4defce3f9e0
+        let patch = patch.min(255);
+        (u32::from(major) << 16) + (u32::from(minor) << 8) + u32::from(patch)
+    }
+
     // This is ported from https://github.com/torvalds/linux/blob/3f01e9f/tools/lib/bpf/libbpf_probes.c#L21-L101.
 
     fn get_ubuntu_kernel_version() -> Result<Option<Self>, CurrentKernelVersionError> {