Commit-ID: 57a2fe90fcdaa812ac1aa6c91ba0e591c30f461a
Gitweb: http://git.kernel.org/tip/57a2fe90fcdaa812ac1aa6c91ba0e591c30f461a
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Fri, 31 Jan 2014 12:58:39 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 23 Feb 2014 09:03:16 -0800
rcutorture: Apply ACCESS_ONCE() to racy fullstop accesses
Because the fullstop variable can be accessed while it is being updated,
this commit avoids any resulting compiler mischief through use of
ACCESS_ONCE() for non-initialization accesses to this shared variable.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/torture.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/kernel/torture.c b/kernel/torture.c
index b30c2ee..1bafd02 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -439,9 +439,9 @@ static int torture_shutdown_notify(struct notifier_block *unused1,
unsigned long unused2, void *unused3)
{
mutex_lock(&fullstop_mutex);
- if (fullstop == FULLSTOP_DONTSTOP) {
+ if (ACCESS_ONCE(fullstop) == FULLSTOP_DONTSTOP) {
VERBOSE_TOROUT_STRING("Unscheduled system shutdown detected");
- fullstop = FULLSTOP_SHUTDOWN;
+ ACCESS_ONCE(fullstop) = FULLSTOP_SHUTDOWN;
} else {
pr_warn("Concurrent rmmod and shutdown illegal!\n");
}
@@ -575,13 +575,13 @@ EXPORT_SYMBOL_GPL(torture_init_end);
bool torture_cleanup(void)
{
mutex_lock(&fullstop_mutex);
- if (fullstop == FULLSTOP_SHUTDOWN) {
+ if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
pr_warn("Concurrent rmmod and shutdown illegal!\n");
mutex_unlock(&fullstop_mutex);
schedule_timeout_uninterruptible(10);
return true;
}
- fullstop = FULLSTOP_RMMOD;
+ ACCESS_ONCE(fullstop) = FULLSTOP_RMMOD;
mutex_unlock(&fullstop_mutex);
unregister_reboot_notifier(&torture_shutdown_nb);
torture_shuffle_cleanup();
@@ -605,6 +605,6 @@ EXPORT_SYMBOL_GPL(torture_must_stop);
*/
bool torture_must_stop_irq(void)
{
- return fullstop != FULLSTOP_DONTSTOP;
+ return ACCESS_ONCE(fullstop) != FULLSTOP_DONTSTOP;
}
EXPORT_SYMBOL_GPL(torture_must_stop_irq);
--
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