From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com,
Davidlohr Bueso <dave@stgolabs.net>,
Davidlohr Bueso <dbueso@suse.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 17/20] locking/locktorture: Fix num reader/writer corner cases
Date: Fri, 1 Dec 2017 12:09:02 -0800 [thread overview]
Message-ID: <1512158945-27269-17-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171201200819.GA25519@linux.vnet.ibm.com>
From: Davidlohr Bueso <dave@stgolabs.net>
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: Jeremy Linton <jeremy.linton@arm.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
---
kernel/locking/locktorture.c | 76 +++++++++++++++++++++++++-------------------
1 file changed, 44 insertions(+), 32 deletions(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index a307a79e6b0b..2a1fc2a58910 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -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();
@@ -909,17 +915,19 @@ 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) {
+ VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
- lock_is_write_held = 0;
- cxt.lwsa = kmalloc(sizeof(*cxt.lwsa) * cxt.nrealwriters_stress, GFP_KERNEL);
- if (cxt.lwsa == NULL) {
- VERBOSE_TOROUT_STRING("cxt.lwsa: Out of memory");
- 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;
+ 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) {
@@ -936,19 +944,21 @@ static int __init lock_torture_init(void)
cxt.nrealreaders_stress = cxt.nrealwriters_stress;
}
- lock_is_read_held = 0;
- cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
- if (cxt.lrsa == NULL) {
- VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
- firsterr = -ENOMEM;
- kfree(cxt.lwsa);
- cxt.lwsa = NULL;
- goto unwind;
- }
-
- for (i = 0; i < cxt.nrealreaders_stress; i++) {
- cxt.lrsa[i].n_lock_fail = 0;
- cxt.lrsa[i].n_lock_acquired = 0;
+ if (nreaders_stress) {
+ lock_is_read_held = 0;
+ cxt.lrsa = kmalloc(sizeof(*cxt.lrsa) * cxt.nrealreaders_stress, GFP_KERNEL);
+ if (cxt.lrsa == NULL) {
+ VERBOSE_TOROUT_STRING("cxt.lrsa: Out of memory");
+ firsterr = -ENOMEM;
+ kfree(cxt.lwsa);
+ cxt.lwsa = NULL;
+ goto unwind;
+ }
+
+ for (i = 0; i < cxt.nrealreaders_stress; i++) {
+ cxt.lrsa[i].n_lock_fail = 0;
+ cxt.lrsa[i].n_lock_acquired = 0;
+ }
}
}
@@ -978,12 +988,14 @@ static int __init lock_torture_init(void)
goto unwind;
}
- writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
- GFP_KERNEL);
- if (writer_tasks == NULL) {
- VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
- firsterr = -ENOMEM;
- goto unwind;
+ if (nwriters_stress) {
+ writer_tasks = kzalloc(cxt.nrealwriters_stress * sizeof(writer_tasks[0]),
+ GFP_KERNEL);
+ if (writer_tasks == NULL) {
+ VERBOSE_TOROUT_ERRSTRING("writer_tasks: Out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
}
if (cxt.cur_ops->readlock) {
--
2.5.2
next prev parent reply other threads:[~2017-12-01 20:12 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-01 20:08 [PATCH tip/core/rcu 0/20] Torture-test updates for v4.16 Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 01/20] torture: Suppress CPU stall warnings during shutdown ftrace dump Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK Paul E. McKenney
2017-12-04 12:32 ` David Laight
2017-12-04 13:42 ` Paul E. McKenney
2017-12-04 14:13 ` David Laight
2017-12-04 16:11 ` Paul E. McKenney
2017-12-10 12:52 ` Andy Shevchenko
2017-12-10 18:51 ` Paul E. McKenney
2017-12-10 20:39 ` Linus Torvalds
2017-12-10 21:47 ` Paul E. McKenney
2017-12-11 19:59 ` Kees Cook
2017-12-12 16:08 ` Paul E. McKenney
[not found] ` <87wp1sa55h.fsf@concordia.ellerman.id.au>
[not found] ` <CA+55aFxHdAX_ztDMUyXihhUv_eftntHecGUUaV3qAtGj_ZbKCg@mail.gmail.com>
2017-12-13 12:59 ` Long live %pK (was Re: [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK) Michael Ellerman
2017-12-13 18:21 ` Linus Torvalds
2017-12-01 20:08 ` [PATCH tip/core/rcu 03/20] rcutorture: Change printk() %p to %pK Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 04/20] torture: Reduce #ifdefs for preempt_schedule() Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 05/20] rcutorture: Preempt RCU-preempt readers more vigorously Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 06/20] rcutorture/configinit: Fix build directory error message Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 07/20] rcutorture: Remove unused script, config2frag.sh Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 08/20] rcutorture/kvm.sh: Remove unused variable, `alldone` Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 09/20] rcutorture/kvm.sh: Use consistent help text for --qemu-args Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 10/20] rcutorture/kvm.sh: Support execution from any directory Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 11/20] rcutorture/kvm-recheck-*: Improve result directory readability check Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 12/20] rcutorture: Simplify logging Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 13/20] rcutorture: Simplify functions.sh include path Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 14/20] rcutorture/kvm-build.sh: Skip build directory check Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 15/20] torture: Place all torture-test modules in one MAINTAINERS group Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 16/20] locking/locktorture: Fix rwsem reader_delay Paul E. McKenney
2017-12-01 20:09 ` Paul E. McKenney [this message]
2017-12-01 20:09 ` [PATCH tip/core/rcu 18/20] torture: Make stutter less vulnerable to compilers and races Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 19/20] torture: Eliminate torture_runnable and perf_runnable Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 20/20] torture: Save a line in stutter_wait(): while -> for Paul E. McKenney
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