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authorPaul E. McKenney <paulmck@linux.ibm.com>2019-04-09 11:06:32 -0700
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-05-28 09:06:09 -0700
commite8516c64fe97e27a28fd5bc65b616508ae0020cf (patch)
treea8735dcac32c1d817849495ab010617213de8657 /kernel/torture.c
parent140e53f20b159722903f0c87358bcd809aa9767e (diff)
rcutorture: Fix stutter_wait() return value and freelist checks
The stutter_wait() function is supposed to return true if it actually waits and false otherwise, but it instead unconditionally returns false. Which hides a bug in rcu_torture_writer() that fails to account for the fact that one of the rcu_tortures[] array elements will normally be referenced by rcu_torture_current, and thus not be on the freelist. This commit therefore corrects the stutter_wait() return value and adds a check for rcu_torture_current to rcu_torture_writer()'s check that things get freed after everything goes quiescent. In addition, this commit causes torture_stutter() to give a bit more than one second (instead of only one jiffy) warning of the end of the stutter interval. Finally, this commit disables long-delay readers and aggressive update-side forward-progress checks while forward-progress testing is in flight. Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/torture.c')
-rw-r--r--kernel/torture.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/kernel/torture.c b/kernel/torture.c
index 17b2be9bde12..de0e0ecf88e1 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -578,10 +578,12 @@ static int stutter;
bool stutter_wait(const char *title)
{
int spt;
+ bool ret = false;
cond_resched_tasks_rcu_qs();
spt = READ_ONCE(stutter_pause_test);
for (; spt; spt = READ_ONCE(stutter_pause_test)) {
+ ret = true;
if (spt == 1) {
schedule_timeout_interruptible(1);
} else if (spt == 2) {
@@ -592,7 +594,7 @@ bool stutter_wait(const char *title)
}
torture_shutdown_absorb(title);
}
- return !!spt;
+ return ret;
}
EXPORT_SYMBOL_GPL(stutter_wait);
@@ -602,13 +604,20 @@ EXPORT_SYMBOL_GPL(stutter_wait);
*/
static int torture_stutter(void *arg)
{
+ int wtime;
+
VERBOSE_TOROUT_STRING("torture_stutter task started");
do {
if (!torture_must_stop() && stutter > 1) {
- WRITE_ONCE(stutter_pause_test, 1);
- schedule_timeout_interruptible(stutter - 1);
+ wtime = stutter;
+ if (stutter > HZ + 1) {
+ WRITE_ONCE(stutter_pause_test, 1);
+ wtime = stutter - HZ - 1;
+ schedule_timeout_interruptible(wtime);
+ wtime = HZ + 1;
+ }
WRITE_ONCE(stutter_pause_test, 2);
- schedule_timeout_interruptible(1);
+ schedule_timeout_interruptible(wtime);
}
WRITE_ONCE(stutter_pause_test, 0);
if (!torture_must_stop())

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