locktorture: Fix nil pointer dereferencing for cleanup paths
It has been found that paths that invoke cleanups through
lock_torture_cleanup() can incur in nil pointer dereferencing
bugs during the statistics printing phase. This is mainly
because we should not be calling into statistics before we are
sure things have been setup correctly.
Specifically, early checks (and the need for handling this in
the cleanup call) only include parameter checks and basic
statistics allocation. Once we start write/read kthreads
we then consider the test as started. As such, update the func
in question to check for cxt.lwsa writer stats, if not set,
we either have a bogus parameter or ENOMEM situation and
therefore only need to deal with general torture calls
Reported-and-tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9e9c5f4..d066a50 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -748,6 +748,15 @@
if (torture_cleanup_begin())
return;
+ /*
+ * Indicates early cleanup, meaning that the test has not run,
+ * such as when passing bogus args when loading the module. As
+ * such, only perform the underlying torture-specific cleanups,
+ * and avoid anything related to locktorture.
+ */
+ if (!cxt.lwsa)
+ goto end;
+
if (writer_tasks) {
for (i = 0; i < cxt.nrealwriters_stress; i++)
torture_stop_kthread(lock_torture_writer,
@@ -776,6 +785,7 @@
else
lock_torture_print_module_parms(cxt.cur_ops,
"End of test: SUCCESS");
+end:
torture_cleanup_end();
}
@@ -870,6 +880,7 @@
VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
firsterr = -ENOMEM;
kfree(cxt.lwsa);
+ cxt.lwsa = NULL;
goto unwind;
}
@@ -878,6 +889,7 @@
cxt.lrsa[i].n_lock_acquired = 0;
}
}
+
lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
/* Prepare torture context. */
