BUG/MEDIUM: debug: make the debug_handler check for the thread in threads_to_dump

It happens that just sending the debug signal to the process makes on
thread wait for its turn while nobody wants to dump. We need to at
least verify that a dump was really requested for this thread.

This can be backported to 2.1 and 2.0.

diff --git a/src/debug.c b/src/debug.c
index 3c18ff0801c7e1b90116061f784b32cb98c100f9..0cd6ef1a825b66c4af553b78789894a7769ae5b4 100644 (file)
--- a/src/debug.c
+++ b/src/debug.c
@@ -645,6 +645,12 @@ void ha_thread_dump_all_to_trash()
 /* handles DEBUGSIG to dump the state of the thread it's working on */
 void debug_handler(int sig, siginfo_t *si, void *arg)
 {
+       /* first, let's check it's really for us and that we didn't just get
+        * a spurious DEBUGSIG.
+        */
+       if (!(threads_to_dump & tid_bit))
+               return;
+
        /* There are 4 phases in the dump process:
         *   1- wait for our turn, i.e. when all lower bits are gone.
         *   2- perform the action if our bit is set