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authorDavidlohr Bueso <dave@stgolabs.net>2014-09-11 20:40:21 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2014-09-16 13:41:06 -0700
commitd36a7a0d5e8b5bff1671723d733eb61621b0cee4 (patch)
tree17cbd1c2542a4b587890a593446757606a4a7834 /kernel/torture.c
parent1e6757a92189278c484799ea98fc69bdc528940e (diff)
downloadlinux-d36a7a0d5e8b5bff1671723d733eb61621b0cee4.tar.gz
torture: Address race in module cleanup
When performing module cleanups by calling torture_cleanup() the 'torture_type' string in nullified However, callers are not necessarily done, and might still need to reference the variable. This impacts both rcutorture and locktorture, causing printing things like: [ 94.226618] (null)-torture: Stopping lock_torture_writer task [ 94.226624] (null)-torture: Stopping lock_torture_stats task Thus delay this operation until the very end of the cleanup process. The consequence (which shouldn't matter for this kid of program) is, of course, that we delay the window between rmmod and modprobing, for instance in module_torture_begin(). Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/torture.c')
-rw-r--r--kernel/torture.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/torture.c b/kernel/torture.c
index ede8b25ec1ae..dd70993c266c 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -633,8 +633,13 @@ EXPORT_SYMBOL_GPL(torture_init_end);
*
* This must be called before the caller starts shutting down its own
* kthreads.
+ *
+ * Both torture_cleanup_begin() and torture_cleanup_end() must be paired,
+ * in order to correctly perform the cleanup. They are separated because
+ * threads can still need to reference the torture_type type, thus nullify
+ * only after completing all other relevant calls.
*/
-bool torture_cleanup(void)
+bool torture_cleanup_begin(void)
{
mutex_lock(&fullstop_mutex);
if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
@@ -649,12 +654,17 @@ bool torture_cleanup(void)
torture_shuffle_cleanup();
torture_stutter_cleanup();
torture_onoff_cleanup();
+ return false;
+}
+EXPORT_SYMBOL_GPL(torture_cleanup_begin);
+
+void torture_cleanup_end(void)
+{
mutex_lock(&fullstop_mutex);
torture_type = NULL;
mutex_unlock(&fullstop_mutex);
- return false;
}
-EXPORT_SYMBOL_GPL(torture_cleanup);
+EXPORT_SYMBOL_GPL(torture_cleanup_end);
/*
* Is it time for the current torture test to stop?