From 3788e32516530dee66cf9186f846480a16799b05 Mon Sep 17 00:00:00 2001 From: Andrea Righi Date: Sun, 10 May 2026 19:52:11 +0200 Subject: [PATCH] selftests/sched_ext: Fix build error in dequeue selftest Building the dequeue selftest with newer compilers (e.g., gcc 16) triggers the following error: dequeue.c:28:22: error: variable 'sum' set but not used The 'volatile' qualifier prevents the writes from being optimized away, but does not silence the unused variable 'sum' is indeed only written and never read. Consume 'sum' via an empty asm() with a register input constraint. This forces the compiler to keep the accumulated value (preserving the CPU stress loop) and avoiding the build error. Fixes: 658ad2259b3e ("selftests/sched_ext: Add test to validate ops.dequeue() semantics") Signed-off-by: Andrea Righi Signed-off-by: Tejun Heo --- tools/testing/selftests/sched_ext/dequeue.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/testing/selftests/sched_ext/dequeue.c b/tools/testing/selftests/sched_ext/dequeue.c index 4e93262703ca..383d06e972a4 100644 --- a/tools/testing/selftests/sched_ext/dequeue.c +++ b/tools/testing/selftests/sched_ext/dequeue.c @@ -33,6 +33,7 @@ static void worker_fn(int id) /* Do some work to trigger scheduling events */ for (j = 0; j < 10000; j++) sum += j; + asm volatile("" : : "r"(sum)); /* Sleep to trigger dequeue */ usleep(1000 + (id * 100));