Commit 988369d2 authored by David Carlier's avatar David Carlier Committed by Tejun Heo
Browse files

tools/sched_ext: scx_central: fix sched_setaffinity() call with the set size 



The cpu set is dynamically allocated for nr_cpu_ids using CPU_ALLOC(),
so the size passed to sched_setaffinity() should be CPU_ALLOC_SIZE()
rather than sizeof(cpu_set_t). Valgrind flagged this as accessing
unaddressable bytes past the allocation.

Signed-off-by: default avatarDavid Carlier <devnexen@gmail.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 11fece49

tools/sched_ext/scx_central.c

+4 −2
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ int main(int argc, char **argv) 
	__u64 seq = 0, ecode;

	__s32 opt;

	cpu_set_t *cpuset;

	size_t cpuset_size;



	libbpf_set_print(libbpf_print_fn);

	signal(SIGINT, sigint_handler);
@@ -106,9 +107,10 @@ int main(int argc, char **argv) 
	 */

	cpuset = CPU_ALLOC(skel->rodata->nr_cpu_ids);

	SCX_BUG_ON(!cpuset, "Failed to allocate cpuset");

	CPU_ZERO_S(CPU_ALLOC_SIZE(skel->rodata->nr_cpu_ids), cpuset);

	cpuset_size = CPU_ALLOC_SIZE(skel->rodata->nr_cpu_ids);

	CPU_ZERO_S(cpuset_size, cpuset);

	CPU_SET(skel->rodata->central_cpu, cpuset);

	SCX_BUG_ON(sched_setaffinity(0, sizeof(*cpuset), cpuset),

	SCX_BUG_ON(sched_setaffinity(0, cpuset_size, cpuset),

		   "Failed to affinitize to central CPU %d (max %d)",

		   skel->rodata->central_cpu, skel->rodata->nr_cpu_ids - 1);

	CPU_FREE(cpuset);