From 34ff636f322c6d5e4f0a52338fa63a7dff09a495 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sat, 18 Jul 2026 13:15:36 -0400 Subject: [PATCH 1/2] scftorture: Count single_rpc offline failures in statistics output scf_torture_stats_print() aggregates each invoker thread's counters into a local scf_statistics structure before printing, but the n_single_rpc_ofl field is missing from the aggregation loop. As a result, the "single_rpc_ofl" value printed in the statistics line is always zero, even when smp_call_function_single() invocations for the RPC test have failed due to offline CPUs and been counted by the invoker threads. Add the missing accumulation so that the printed value reflects the actual counts. Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- kernel/scftorture.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/scftorture.c b/kernel/scftorture.c index 327c315f411c..ffd6c83732ee 100644 --- a/kernel/scftorture.c +++ b/kernel/scftorture.c @@ -193,6 +193,7 @@ static void scf_torture_stats_print(void) scfs.n_single += scf_stats_p[i].n_single; scfs.n_single_ofl += scf_stats_p[i].n_single_ofl; scfs.n_single_rpc += scf_stats_p[i].n_single_rpc; + scfs.n_single_rpc_ofl += scf_stats_p[i].n_single_rpc_ofl; scfs.n_single_wait += scf_stats_p[i].n_single_wait; scfs.n_single_wait_ofl += scf_stats_p[i].n_single_wait_ofl; scfs.n_many += scf_stats_p[i].n_many; From 8b5b048277e2c43b9012f0196f4097c4e92025a1 Mon Sep 17 00:00:00 2001 From: Joel Fernandes Date: Sat, 18 Jul 2026 13:15:37 -0400 Subject: [PATCH 2/2] scftorture: Make invoker threads actually wait for all threads to start Each scftorture_invoker() thread decrements n_started, which is initialized to the number of threads, and is then supposed to wait until all of its siblings have also checked in before starting the test proper. However, the wait loop is guarded by !atomic_dec_return(&n_started), which is true only for the final thread to arrive, and by then n_started is already zero, so the final thread does not wait either. The side-effect (possibly positive) is that no thread ever waits and the start-synchronization barrier is dead code, with early threads beginning to hammer smp_call_function*() while later threads are still being spawned. Invert the test so that every thread other than the last spins until n_started reaches zero, making the threads start testing together as intended. The existing torture_must_stop() check in the wait loop continues to bound the wait during shutdown. We can also drop the spinning entirely if the intent is to leave it as dead code, however for the current intent, this patches fixes the code. Signed-off-by: Joel Fernandes Signed-off-by: Paul E. McKenney --- kernel/scftorture.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/scftorture.c b/kernel/scftorture.c index ffd6c83732ee..392df1b4d4ed 100644 --- a/kernel/scftorture.c +++ b/kernel/scftorture.c @@ -497,7 +497,7 @@ static int scftorture_invoker(void *arg) "%s: Wanted CPU %d, running on %d, nr_cpu_ids = %d\n", __func__, scfp->cpu, curcpu, nr_cpu_ids); - if (!atomic_dec_return(&n_started)) + if (atomic_dec_return(&n_started)) while (atomic_read_acquire(&n_started)) { if (torture_must_stop()) { VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);