From: Jens Axboe <axboe@fb.com>
Date: Tue, 25 Feb 2014 19:35:27 +0000 (-0800)
Subject: Ensure that fio_get_kb_base() doesn't assume 'data' is thread_options
X-Git-Tag: fio-2.1.6~17
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=cb1402d674fb7694d1b09d7ef4aeb3d4506f23f0

Ensure that fio_get_kb_base() doesn't assume 'data' is thread_options

Nasty hack, but at least we don't corrupt option data.

Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/options.c b/options.c
index 53559829..625d3a25 100644
--- a/options.c
+++ b/options.c
@@ -3790,6 +3790,7 @@ int fio_cmd_ioengine_option_parse(struct thread_data *td, const char *opt,
 
 void fio_fill_default_options(struct thread_data *td)
 {
+	td->o.magic = OPT_MAGIC;
 	fill_default_options(td, fio_options);
 }
 
@@ -3834,7 +3835,16 @@ unsigned int fio_get_kb_base(void *data)
 	struct thread_options *o = data;
 	unsigned int kb_base = 0;
 
-	if (o)
+	/*
+	 * This is a hack... For private options, *data is not holding
+	 * a pointer to the thread_options, but to private data. This means
+	 * we can't safely dereference it, but magic is first so mem wise
+	 * it is valid. But this also means that if the job first sets
+	 * kb_base and expects that to be honored by private options,
+	 * it will be disappointed. We will return the global default
+	 * for this.
+	 */
+	if (o && o->magic == OPT_MAGIC)
 		kb_base = o->kb_base;
 	if (!kb_base)
 		kb_base = 1024;
diff --git a/thread_options.h b/thread_options.h
index b7a88ed3..14a4e54a 100644
--- a/thread_options.h
+++ b/thread_options.h
@@ -28,8 +28,10 @@ struct bssplit {
 	uint32_t perc;
 };
 
+#define OPT_MAGIC	0x4f50544e
+
 struct thread_options {
-	int pad;
+	int magic;
 	char *description;
 	char *name;
 	char *directory;