bpf: fix an incorrect inline asm operands and constraints

While searching for using input operands while we should use the output operand, I found the "r+" mistake, that is detected when you fix the operands since the compiler no longer ignores it. Signed-off-by: Mahe Tardy <[email protected]>
cilium · Aug 7, 2024 · 9c96566 · 9c96566
1 parent 6d5802d
commit 9c96566
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/bpf/process/pfilter.h b/bpf/process/pfilter.h
@@ -587,8 +587,8 @@ generic_process_filter(struct bpf_map_def *heap, struct bpf_map_def *fmap)
 		pass = selector_process_filter(f, curr, enter, msg);
 		if (pass) {
 			/* Verify lost that msg is not null here so recheck */
-			asm volatile("%[curr] &= 0x1f;\n" ::[curr] "r+"(curr)
-				     :);
+			asm volatile("%[curr] &= 0x1f;\n"
+				     : [curr] "+r"(curr));
 			sel->active[curr] = true;
 			sel->active[SELECTORS_ACTIVE] = true;
 			sel->pass |= true;