Make main thread killable so that it can be canceled at any time.

Refine comment of makeThreadKillable().

This commit can be backported to 5.0, only if we also backport cf8a6e3.

Co-authored-by: Oran Agra <oran@redislabs.com>
(cherry picked from commit d2291627305d606a5d3b1e3b3bfa17ab10a3ef32)

src/bio.c

@@ -168,10 +168,7 @@ void *bioProcessBackgroundJobs(void *arg) {
 
     redisSetCpuAffinity(server.bio_cpulist);
 
-    /* Make the thread killable at any time, so that bioKillThreads()
-     * can work reliably. */
-    pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
-    pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
+    makeThreadKillable();
 
     pthread_mutex_lock(&bio_mutex[type]);
     /* Block SIGALRM so we are sure that only the main thread will

src/server.c

@@ -2798,12 +2798,21 @@ void resetServerStats(void) {
     server.aof_delayed_fsync = 0;
 }
 
+/* Make the thread killable at any time, so that kill threads functions
+ * can work reliably (default cancelability type is PTHREAD_CANCEL_DEFERRED).
+ * Needed for pthread_cancel used by the fast memory test used by the crash report. */
+void makeThreadKillable(void) {
+    pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
+    pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
+}
+
 void initServer(void) {
     int j;
 
     signal(SIGHUP, SIG_IGN);
     signal(SIGPIPE, SIG_IGN);
     setupSignalHandlers();
+    makeThreadKillable();
 
     if (server.syslog_enabled) {
         openlog(server.syslog_ident, LOG_PID | LOG_NDELAY | LOG_NOWAIT,

src/server.h

@@ -2471,6 +2471,7 @@ void xorDigest(unsigned char *digest, void *ptr, size_t len);
 int populateCommandTableParseFlags(struct redisCommand *c, char *strflags);
 void killIOThreads(void);
 void killThreads(void);
+void makeThreadKillable(void);
 
 /* TLS stuff */
 void tlsInit(void);