nr_cpu_ids / 2 produces stride 0 on a single-CPU system, which later
causes SCX_BUG_ON(i == j) to fire. Validate stride after option
parsing to also catch invalid user-supplied values via -S.
Signed-off-by: David Carlier <devnexen@gmail.com>
---
tools/sched_ext/scx_pair.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/tools/sched_ext/scx_pair.c b/tools/sched_ext/scx_pair.c
index d3e97faa6334..2a82d8a8a0aa 100644
--- a/tools/sched_ext/scx_pair.c
+++ b/tools/sched_ext/scx_pair.c
@@ -56,7 +56,6 @@ int main(int argc, char **argv)
skel = SCX_OPS_OPEN(pair_ops, scx_pair);
skel->rodata->nr_cpu_ids = libbpf_num_possible_cpus();
- assert(skel->rodata->nr_cpu_ids > 0);
skel->rodata->pair_batch_dur_ns = __COMPAT_ENUM_OR_ZERO("scx_public_consts", "SCX_SLICE_DFL");
/* pair up the earlier half to the latter by default, override with -s */
@@ -76,6 +75,12 @@ int main(int argc, char **argv)
}
}
+ /* Stride must be positive to pair distinct CPUs. */
+ if (stride <= 0) {
+ fprintf(stderr, "Invalid stride %d, must be positive\n", stride);
+ scx_pair__destroy(skel);
+ return -1;
+ }
bpf_map__set_max_entries(skel->maps.pair_ctx, skel->rodata->nr_cpu_ids / 2);
/* Resize arrays so their element count is equal to cpu count. */
--
2.51.0