commit 278fb1627351218b23dd33403f08d7521643fda2
author Bauerchen <bauerchen@tencent.com> Mon Apr 06 10:36:54 2020 +0800
committer Paolo Bonzini <pbonzini@redhat.com> Sat Apr 11 08:49:20 2020 -0400
tree 4ef80980b91fe3b59b4a3ff523f18fb1546f7249
parent 9a709f06c87043856307ce824b2ba47e0fdb7621

oslib-posix: take lock before qemu_cond_broadcast

In touch_all_pages, if the mutex is not taken around qemu_cond_broadcast,
qemu_cond_broadcast may be called before all touch page threads enter
qemu_cond_wait. In this case, the touch page threads wait forever for the
main thread to wake them up, causing a deadlock.

Signed-off-by: Bauerchen <bauerchen@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

util/oslib-posix.c

diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 4dd6d7d..062236a 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -492,8 +492,11 @@
                            QEMU_THREAD_JOINABLE);
         addr += memset_thread[i].numpages * hpagesize;
     }
+
+    qemu_mutex_lock(&page_mutex);
     threads_created_flag = true;
     qemu_cond_broadcast(&page_cond);
+    qemu_mutex_unlock(&page_mutex);
 
     for (i = 0; i < memset_num_threads; i++) {
         qemu_thread_join(&memset_thread[i].pgthread);