From 27357187b0899380bae5c6748f2b2d034502e162 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 27 Sep 2012 11:31:50 +0200
Subject: [PATCH] Fix segfault race on exit for platforms that don't have disk
 util support

We still need to quisce the disk util thread, as it also functions
as the runtime ETA status printer.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 backend.c  |  8 ++++++++
 diskutil.c | 10 +++-------
 diskutil.h | 13 ++++++++++---
 3 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/backend.c b/backend.c
index c31d22af..b5501c63 100644
--- a/backend.c
+++ b/backend.c
@@ -67,6 +67,7 @@ unsigned int nr_thread = 0;
 int shm_id = 0;
 int temp_stall_ts;
 unsigned long done_secs = 0;
+volatile int disk_util_exit = 0;
 
 #define PAGE_ALIGN(buf)	\
 	(char *) (((uintptr_t) (buf) + page_mask) & ~page_mask)
@@ -1610,6 +1611,13 @@ void wait_for_disk_thread_exit(void)
 	fio_mutex_down(disk_thread_mutex);
 }
 
+static void free_disk_util(void)
+{
+	disk_util_start_exit();
+	wait_for_disk_thread_exit();
+	disk_util_prune_entries();
+}
+
 static void *disk_thread_main(void *data)
 {
 	int ret = 0;
diff --git a/diskutil.c b/diskutil.c
index d2c0b976..d98e39a5 100644
--- a/diskutil.c
+++ b/diskutil.c
@@ -15,7 +15,6 @@ static int last_majdev, last_mindev;
 static struct disk_util *last_du;
 
 static struct fio_mutex *disk_util_mutex;
-static int disk_util_exit;
 
 FLIST_HEAD(disk_list);
 
@@ -539,16 +538,13 @@ static void aggregate_slaves_stats(struct disk_util *masterdu)
 		agg->max_util.u.f = 100.0;
 }
 
-void free_disk_util(void)
+void disk_util_prune_entries(void)
 {
-	struct disk_util *du;
-
-	disk_util_exit = 1;
-	wait_for_disk_thread_exit();
-
 	fio_mutex_down(disk_util_mutex);
 
 	while (!flist_empty(&disk_list)) {
+		struct disk_util *du;
+
 		du = flist_entry(disk_list.next, struct disk_util, list);
 		flist_del(&du->list);
 		disk_util_free(du);
diff --git a/diskutil.h b/diskutil.h
index b2231502..b89aaccb 100644
--- a/diskutil.h
+++ b/diskutil.h
@@ -3,6 +3,8 @@
 #include "json.h"
 #define FIO_DU_NAME_SZ		64
 
+extern volatile int disk_util_exit;
+
 /*
  * Disk utils as read in /sys/block/<dev>/stat
  */
@@ -102,20 +104,25 @@ extern void wait_for_disk_thread_exit(void);
 #ifdef FIO_HAVE_DISK_UTIL
 extern void print_disk_util(struct disk_util_stat *, struct disk_util_agg *, int terse);
 extern void show_disk_util(int terse, struct json_object *parent);
-extern void free_disk_util(void);
 extern void init_disk_util(struct thread_data *);
 extern int update_io_ticks(void);
 extern void setup_disk_util(void);
+extern void disk_util_prune_entries(void);
 #else
 #define print_disk_util(dus, agg, terse)
 #define show_disk_util(terse, parent)
-#define free_disk_util()
+#define disk_util_prune_entries()
 #define init_disk_util(td)
 #define setup_disk_util()
 static inline int update_io_ticks(void)
 {
-	return 0;
+	return disk_util_exit;
 }
 #endif
 
+static inline void disk_util_start_exit(void)
+{
+	disk_util_exit = 1;
+}
+
 #endif
-- 
2.25.1