From: Boqun Feng <boqun.feng@gmail.com>
To: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org
Cc: Qian Cai <cai@redhat.com>, Boqun Feng <boqun.feng@gmail.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Subject: [PATCH 2/2] lockdep/selftest: Add spin_nest_lock test
Date: Mon, 2 Nov 2020 13:37:42 +0800 [thread overview]
Message-ID: <20201102053743.450459-2-boqun.feng@gmail.com> (raw)
In-Reply-To: <20201102053743.450459-1-boqun.feng@gmail.com>
Add a self test case to test the behavior for the following case:
lock(A);
lock_nest_lock(C1, A);
lock(B);
lock_nest_lock(C2, A);
This is a reproducer for a problem[1] reported by Chris Wilson, and is
helpful to prevent this.
[1]: https://lore.kernel.org/lkml/160390684819.31966.12048967113267928793@build.alporthouse.com/
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
lib/locking-selftest.c | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index afa7d4bb291f..4c24ac8a456c 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -2009,6 +2009,19 @@ static void ww_test_spin_nest_unlocked(void)
U(A);
}
+/* This is not a deadlock, because we have X1 to serialize Y1 and Y2 */
+static void ww_test_spin_nest_lock(void)
+{
+ spin_lock(&lock_X1);
+ spin_lock_nest_lock(&lock_Y1, &lock_X1);
+ spin_lock(&lock_A);
+ spin_lock_nest_lock(&lock_Y2, &lock_X1);
+ spin_unlock(&lock_A);
+ spin_unlock(&lock_Y2);
+ spin_unlock(&lock_Y1);
+ spin_unlock(&lock_X1);
+}
+
static void ww_test_unneeded_slow(void)
{
WWAI(&t);
@@ -2226,6 +2239,10 @@ static void ww_tests(void)
dotest(ww_test_spin_nest_unlocked, FAILURE, LOCKTYPE_WW);
pr_cont("\n");
+ print_testname("spinlock nest test");
+ dotest(ww_test_spin_nest_lock, SUCCESS, LOCKTYPE_WW);
+ pr_cont("\n");
+
printk(" -----------------------------------------------------\n");
printk(" |block | try |context|\n");
printk(" -----------------------------------------------------\n");
--
2.28.0
next prev parent reply other threads:[~2020-11-02 5:38 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-29 14:31 lockdep null-ptr-deref Qian Cai
2020-09-29 23:08 ` Boqun Feng
2020-09-30 9:16 ` Peter Zijlstra
2020-09-30 9:49 ` Peter Zijlstra
2020-09-30 12:18 ` Boqun Feng
2020-09-30 19:02 ` Peter Zijlstra
2020-10-02 12:36 ` Boqun Feng
2020-10-02 13:09 ` Peter Zijlstra
2020-10-02 13:35 ` Boqun Feng
2020-10-02 10:06 ` Peter Zijlstra
2020-10-02 13:40 ` Qian Cai
2020-10-07 16:20 ` [tip: locking/core] lockdep: Fix usage_traceoverflow tip-bot2 for Peter Zijlstra
2020-10-27 11:29 ` Chris Wilson
2020-10-27 11:59 ` Peter Zijlstra
2020-10-27 12:30 ` Peter Zijlstra
2020-10-27 12:48 ` Peter Zijlstra
2020-10-27 14:13 ` Chris Wilson
2020-10-31 11:30 ` [tip: locking/urgent] lockdep: Fix nr_unused_locks accounting tip-bot2 for Peter Zijlstra
2020-10-27 13:29 ` [tip: locking/core] lockdep: Fix usage_traceoverflow Chris Wilson
2020-10-27 15:45 ` Peter Zijlstra
2020-10-27 16:34 ` Chris Wilson
2020-10-28 17:40 ` Chris Wilson
2020-10-28 18:06 ` Chris Wilson
2020-10-28 19:42 ` Peter Zijlstra
2020-10-28 19:59 ` Peter Zijlstra
2020-10-30 3:51 ` Boqun Feng
2020-10-30 9:38 ` Peter Zijlstra
2020-10-30 9:55 ` Peter Zijlstra
2020-11-02 5:37 ` [PATCH 1/2] lockdep: Avoid to modify chain keys in validate_chain() Boqun Feng
2020-11-02 5:37 ` Boqun Feng [this message]
2020-12-03 10:35 ` [tip: locking/core] lockdep/selftest: Add spin_nest_lock test tip-bot2 for Boqun Feng
2020-11-05 6:25 ` [PATCH 1/2] lockdep: Avoid to modify chain keys in validate_chain() Boqun Feng
2020-11-10 17:28 ` Peter Zijlstra
2020-11-11 8:23 ` [tip: locking/urgent] " tip-bot2 for Boqun Feng
2020-10-09 7:58 ` [tip: locking/core] lockdep: Fix usage_traceoverflow tip-bot2 for Peter Zijlstra
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