[Qemu-commits] [COMMIT ee39930] posix-aio-compat: avoid signal race when spawning athread

[Anthony Liguori]

From: malc <address@hidden>

Signed-off-by: malc <address@hidden>

diff --git a/posix-aio-compat.c b/posix-aio-compat.c
index 68cbec8..400d898 100644
--- a/posix-aio-compat.c
+++ b/posix-aio-compat.c
@@ -301,14 +301,9 @@ static size_t handle_aiocb_rw(struct qemu_paiocb *aiocb)
 static void *aio_thread(void *unused)
 {
     pid_t pid;
-    sigset_t set;
 
     pid = getpid();
 
-    /* block all signals */
-    if (sigfillset(&set)) die("sigfillset");
-    if (sigprocmask(SIG_BLOCK, &set, NULL)) die("sigprocmask");
-
     while (1) {
         struct qemu_paiocb *aiocb;
         size_t ret = 0;
@@ -369,9 +364,18 @@ static void *aio_thread(void *unused)
 
 static void spawn_thread(void)
 {
+    sigset_t set, oldset;
+
     cur_threads++;
     idle_threads++;
+
+    /* block all signals */
+    if (sigfillset(&set)) die("sigfillset");
+    if (sigprocmask(SIG_SETMASK, &set, &oldset)) die("sigprocmask");
+
     thread_create(&thread_id, &attr, aio_thread, NULL);
+
+    if (sigprocmask(SIG_SETMASK, &oldset, NULL)) die("sigprocmask restore");
 }
 
 static void qemu_paio_submit(struct qemu_paiocb *aiocb)