The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bf1e15a82e3b74ee86bb119d6038b41e1ed2b319 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Date: Tue, 20 Apr 2021 04:13:03 -0400
Subject: [PATCH] KVM: selftests: Always run vCPU thread with blocked SIG_IPI
The main thread could start to send SIG_IPI at any time, even before signal
blocked on vcpu thread. Therefore, start the vcpu thread with the signal
blocked.
Without this patch, on very busy cores the dirty_log_test could fail directly
on receiving a SIGUSR1 without a handler (when vcpu runs far slower than main).
Reported-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index ffa4e2791926..81edbd23d371 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -527,9 +527,8 @@ static void *vcpu_worker(void *data)
*/
sigmask->len = 8;
pthread_sigmask(0, NULL, sigset);
+ sigdelset(sigset, SIG_IPI);
vcpu_ioctl(vm, VCPU_ID, KVM_SET_SIGNAL_MASK, sigmask);
- sigaddset(sigset, SIG_IPI);
- pthread_sigmask(SIG_BLOCK, sigset, NULL);
sigemptyset(sigset);
sigaddset(sigset, SIG_IPI);
@@ -858,6 +857,7 @@ int main(int argc, char *argv[])
.interval = TEST_HOST_LOOP_INTERVAL,
};
int opt, i;
+ sigset_t sigset;
sem_init(&sem_vcpu_stop, 0, 0);
sem_init(&sem_vcpu_cont, 0, 0);
@@ -916,6 +916,11 @@ int main(int argc, char *argv[])
srandom(time(0));
+ /* Ensure that vCPU threads start with SIG_IPI blocked. */
+ sigemptyset(&sigset);
+ sigaddset(&sigset, SIG_IPI);
+ pthread_sigmask(SIG_BLOCK, &sigset, NULL);
+
if (host_log_mode_option == LOG_MODE_ALL) {
/* Run each log mode */
for (i = 0; i < LOG_MODE_NUM; i++) {
