From: Willy Tarreau <w@1wt.eu>
Date: Wed, 22 Nov 2023 17:30:19 +0000 (+0100)
Subject: MINOR: debug: copy the thread info into the post_mortem struct
X-Git-Tag: v2.9-dev11~20
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=37e3dd718cba8ebea1a723ad49871d582829af92;p=thirdparty%2Fhaproxy.git

MINOR: debug: copy the thread info into the post_mortem struct

The last starting thread now copies the pthread ID and stack top of
each thread into post_mortem. That way it's as easy as issuing
"p post_mortem" in gdb to see all thread IDs and stack frames and more
easily map them to the threads met in a core.
---

diff --git a/src/debug.c b/src/debug.c
index 78d913696f..837061505d 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -98,6 +98,13 @@ struct post_mortem {
 		gid_t boot_gid;
 		struct rlimit limit_fd;  // RLIMIT_NOFILE
 		struct rlimit limit_ram; // RLIMIT_AS or RLIMIT_DATA
+
+#if defined(USE_THREAD)
+		struct {
+			ullong pth_id;   // pthread_t cast to a ullong
+			void *stack_top; // top of the stack
+		} thread_info[MAX_THREADS];
+#endif
 	} process;
 } post_mortem ALIGNED(256) = { };
 
@@ -2145,6 +2152,28 @@ static int feed_post_mortem()
 
 REGISTER_POST_CHECK(feed_post_mortem);
 
+#ifdef USE_THREAD
+/* init code is called one at a time so let's collect all per-thread info on
+ * the last starting thread. These info are not critical anyway and there's no
+ * problem if we get them slightly late.
+ */
+static int feed_post_mortem_late()
+{
+	static int per_thread_info_collected;
+
+	if (HA_ATOMIC_ADD_FETCH(&per_thread_info_collected, 1) == global.nbthread) {
+		int i;
+		for (i = 0; i < global.nbthread; i++) {
+			post_mortem.process.thread_info[i].pth_id = ha_thread_info[i].pth_id;
+			post_mortem.process.thread_info[i].stack_top = ha_thread_info[i].stack_top;
+		}
+	}
+	return 1;
+}
+
+REGISTER_PER_THREAD_INIT(feed_post_mortem_late);
+#endif
+
 /* register cli keywords */
 static struct cli_kw_list cli_kws = {{ },{
 	{{ "debug", "dev", "bug", NULL },      "debug dev bug                           : call BUG_ON() and crash",                 debug_parse_cli_bug,   NULL, NULL, NULL, ACCESS_EXPERT },