From: Peng Liu <liupeng256@huawei.com>
To: <brendanhiggins@google.com>, <glider@google.com>,
<elver@google.com>, <dvyukov@google.com>,
<akpm@linux-foundation.org>, <linux-kselftest@vger.kernel.org>,
<kunit-dev@googlegroups.com>, <linux-kernel@vger.kernel.org>,
<kasan-dev@googlegroups.com>, <linux-mm@kvack.org>
Cc: <wangkefeng.wang@huawei.com>, <liupeng256@huawei.com>
Subject: [PATCH v2 3/3] kfence: test: try to avoid test_gfpzero trigger rcu_stall
Date: Wed, 9 Mar 2022 08:37:53 +0000 [thread overview]
Message-ID: <20220309083753.1561921-4-liupeng256@huawei.com> (raw)
In-Reply-To: <20220309083753.1561921-1-liupeng256@huawei.com>
When CONFIG_KFENCE_NUM_OBJECTS is set to a big number, kfence
kunit-test-case test_gfpzero will eat up nearly all the CPU's
resources and rcu_stall is reported as the following log which
is cut from a physical server.
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 68-....: (14422 ticks this GP) idle=6ce/1/0x4000000000000002
softirq=592/592 fqs=7500 (t=15004 jiffies g=10677 q=20019)
Task dump for CPU 68:
task:kunit_try_catch state:R running task
stack: 0 pid: 9728 ppid: 2 flags:0x0000020a
Call trace:
dump_backtrace+0x0/0x1e4
show_stack+0x20/0x2c
sched_show_task+0x148/0x170
...
rcu_sched_clock_irq+0x70/0x180
update_process_times+0x68/0xb0
tick_sched_handle+0x38/0x74
...
gic_handle_irq+0x78/0x2c0
el1_irq+0xb8/0x140
kfree+0xd8/0x53c
test_alloc+0x264/0x310 [kfence_test]
test_gfpzero+0xf4/0x840 [kfence_test]
kunit_try_run_case+0x48/0x20c
kunit_generic_run_threadfn_adapter+0x28/0x34
kthread+0x108/0x13c
ret_from_fork+0x10/0x18
To avoid rcu_stall and unacceptable latency, a schedule point is
added to test_gfpzero.
Signed-off-by: Peng Liu <liupeng256@huawei.com>
---
mm/kfence/kfence_test.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index caed6b4eba94..1b50f70a4c0f 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -627,6 +627,7 @@ static void test_gfpzero(struct kunit *test)
kunit_warn(test, "giving up ... cannot get same object back\n");
return;
}
+ cond_resched();
}
for (i = 0; i < size; i++)
--
2.18.0.huawei.25
next prev parent reply other threads:[~2022-03-09 8:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-09 8:37 [PATCH v2 0/3] kunit: fix a UAF bug and do some optimization Peng Liu
2022-03-09 8:37 ` [PATCH v2 1/3] kunit: fix UAF when run kfence test case test_gfpzero Peng Liu
2022-03-09 10:03 ` Marco Elver
2022-03-10 8:08 ` Brendan Higgins
2022-03-09 8:37 ` [PATCH v2 2/3] kunit: make kunit_test_timeout compatible with comment Peng Liu
2022-03-09 10:04 ` Marco Elver
2022-03-09 13:53 ` Daniel Latypov
2022-03-10 8:10 ` Brendan Higgins
2022-03-09 8:37 ` Peng Liu [this message]
2022-03-09 8:31 ` [PATCH v2 3/3] kfence: test: try to avoid test_gfpzero trigger rcu_stall Marco Elver
2022-03-10 8:07 ` [PATCH v2 0/3] kunit: fix a UAF bug and do some optimization Brendan Higgins
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