From 5d9332266deb33c46a64abfcbbdfa025ab1100e1 Mon Sep 17 00:00:00 2001
From: WuYunlong <xzsyeb@126.com>
Date: Tue, 15 Sep 2020 13:06:47 +0800
Subject: [PATCH] bio: fix doFastMemoryTest.

If one thread got SIGSEGV, function sigsegvHandler() would be triggered,
it would call bioKillThreads(). But call pthread_cancel() to cancel itself
would make it block. Also note that if SIGSEGV is caught by bio thread, it
should kill the main thread in order to give a positive report.

(cherry picked from commit 8b70cb0ef8e654d09d0d2974ad72388f46be9fde)
---
 src/bio.c    |  3 ++-
 src/debug.c  | 22 +++++++++++++++++++++-
 src/server.c |  2 +-
 src/server.h |  1 +
 4 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/bio.c b/src/bio.c
index 69c62fc6f..33465a166 100644
--- a/src/bio.c
+++ b/src/bio.c
@@ -268,10 +268,11 @@ void bioKillThreads(void) {
     int err, j;
 
     for (j = 0; j < BIO_NUM_OPS; j++) {
+        if (bio_threads[j] == pthread_self()) continue;
         if (bio_threads[j] && pthread_cancel(bio_threads[j]) == 0) {
             if ((err = pthread_join(bio_threads[j],NULL)) != 0) {
                 serverLog(LL_WARNING,
-                    "Bio thread for job type #%d can be joined: %s",
+                    "Bio thread for job type #%d can not be joined: %s",
                         j, strerror(err));
             } else {
                 serverLog(LL_WARNING,
diff --git a/src/debug.c b/src/debug.c
index 921c681a5..178893bae 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -1512,6 +1512,26 @@ int memtest_test_linux_anonymous_maps(void) {
 }
 #endif
 
+static void killMainThread(void) {
+    int err;
+    if (pthread_self() != server.main_thread_id && pthread_cancel(server.main_thread_id) == 0) {
+        if ((err = pthread_join(server.main_thread_id,NULL)) != 0) {
+            serverLog(LL_WARNING, "main thread can not be joined: %s", strerror(err));
+        } else {
+            serverLog(LL_WARNING, "main thread terminated");
+        }
+    }
+}
+
+/* Kill the running threads (other than current) in an unclean way. This function
+ * should be used only when it's critical to stop the threads for some reason.
+ * Currently Redis does this only on crash (for instance on SIGSEGV) in order
+ * to perform a fast memory check without other threads messing with memory. */
+static void killThreads(void) {
+    killMainThread();
+    bioKillThreads();
+}
+
 /* Scans the (assumed) x86 code starting at addr, for a max of `len`
  * bytes, searching for E8 (callq) opcodes, and dumping the symbols
  * and the call offset if they appear to be valid. */
@@ -1589,7 +1609,7 @@ void sigsegvHandler(int sig, siginfo_t *info, void *secret) {
 #if defined(HAVE_PROC_MAPS)
     /* Test memory */
     serverLogRaw(LL_WARNING|LL_RAW, "\n------ FAST MEMORY TEST ------\n");
-    bioKillThreads();
+    killThreads();
     if (memtest_test_linux_anonymous_maps()) {
         serverLogRaw(LL_WARNING|LL_RAW,
             "!!! MEMORY ERROR DETECTED! Check your memory ASAP !!!\n");
diff --git a/src/server.c b/src/server.c
index 06dcc5d9e..37e3c37df 100644
--- a/src/server.c
+++ b/src/server.c
@@ -2814,6 +2814,7 @@ void initServer(void) {
     server.aof_state = server.aof_enabled ? AOF_ON : AOF_OFF;
     server.hz = server.config_hz;
     server.pid = getpid();
+    server.main_thread_id = pthread_self();
     server.current_client = NULL;
     server.fixed_time_expire = 0;
     server.clients = listCreate();
@@ -5091,7 +5092,6 @@ int iAmMaster(void) {
             (server.cluster_enabled && nodeIsMaster(server.cluster->myself)));
 }
 
-
 int main(int argc, char **argv) {
     struct timeval tv;
     int j;
diff --git a/src/server.h b/src/server.h
index 6a130879e..a1ce26cc2 100644
--- a/src/server.h
+++ b/src/server.h
@@ -1050,6 +1050,7 @@ struct clusterState;
 struct redisServer {
     /* General */
     pid_t pid;                  /* Main process pid. */
+    pthread_t main_thread_id;         /* Main thread id */
     char *configfile;           /* Absolute config file path, or NULL */
     char *executable;           /* Absolute executable file path. */
     char **exec_argv;           /* Executable argv vector (copy). */