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Commit 2ce77d16 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Paul E. McKenney
Browse files

locking/locktorture: Fix num reader/writer corner cases 



Things can explode for locktorture if the user does combinations
of nwriters_stress=0 nreaders_stress=0. Fix this by not assuming
we always want to torture writer threads.

Reported-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: default avatarJeremy Linton <jeremy.linton@arm.com>
Tested-by: default avatarJeremy Linton <jeremy.linton@arm.com>
parent f2f76260

kernel/locking/locktorture.c

+44 −32
Original line number Diff line number Diff line
@@ -703,8 +703,7 @@ static void __torture_print_stats(char *page, 
{

	bool fail = 0;

	int i, n_stress;

	long max = 0;

	long min = statp[0].n_lock_acquired;

	long max = 0, min = statp ? statp[0].n_lock_acquired : 0;

	long long sum = 0;



	n_stress = write ? cxt.nrealwriters_stress : cxt.nrealreaders_stress;
@@ -811,7 +810,7 @@ static void lock_torture_cleanup(void) 
	 * such, only perform the underlying torture-specific cleanups,

	 * and avoid anything related to locktorture.

	 */

	if (!cxt.lwsa)

	if (!cxt.lwsa && !cxt.lrsa)

		goto end;



	if (writer_tasks) {
@@ -886,6 +885,13 @@ static int __init lock_torture_init(void) 
		firsterr = -EINVAL;

		goto unwind;

	}



	if (nwriters_stress == 0 && nreaders_stress == 0) {

		pr_alert("lock-torture: must run at least one locking thread\n");

		firsterr = -EINVAL;

		goto unwind;

	}



	if (cxt.cur_ops->init)

		cxt.cur_ops->init();
@@ -909,7 +915,7 @@ static int __init lock_torture_init(void) 
#endif



	/* Initialize the statistics so that each run gets its own numbers. */



	if (nwriters_stress) {

		lock_is_write_held = 0;

		cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);

		if (cxt.lwsa == NULL) {
@@ -917,10 +923,12 @@ static int __init lock_torture_init(void) 
			firsterr = -ENOMEM;

			goto unwind;

		}



		for (i = 0; i < cxt.nrealwriters_stress; i++) {

			cxt.lwsa[i].n_lock_fail = 0;

			cxt.lwsa[i].n_lock_acquired = 0;

		}

	}



	if (cxt.cur_ops->readlock) {

		if (nreaders_stress >= 0)
@@ -936,6 +944,7 @@ static int __init lock_torture_init(void) 
			cxt.nrealreaders_stress = cxt.nrealwriters_stress;

		}



		if (nreaders_stress) {

			lock_is_read_held = 0;

			cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);

			if (cxt.lrsa == NULL) {
@@ -951,6 +960,7 @@ static int __init lock_torture_init(void) 
				cxt.lrsa[i].n_lock_acquired = 0;

			}

		}

	}



	lock_torture_print_module_parms(cxt.cur_ops, "Start of test");
@@ -978,6 +988,7 @@ static int __init lock_torture_init(void) 
			goto unwind;

	}



	if (nwriters_stress) {

		writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),

				       GFP_KERNEL);

		if (writer_tasks == NULL) {
@@ -985,6 +996,7 @@ static int __init lock_torture_init(void) 
			firsterr = -ENOMEM;

			goto unwind;

		}

	}



	if (cxt.cur_ops->readlock) {

		reader_tasks = kzalloc(cxt.nrealreaders_stress * sizeof(reader_tasks[0]),