From: "tip-bot2 for Boqun Feng" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Boqun Feng <boqun.feng@gmail.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [tip: locking/core] locking/selftest: Add test cases for queued_read_lock()
Date: Thu, 27 Aug 2020 07:54:15 -0000 [thread overview]
Message-ID: <159851485506.20229.16118500942576736080.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20200807074238.1632519-19-boqun.feng@gmail.com>
The following commit has been merged into the locking/core branch of tip:
Commit-ID: ad56450db86413ff911eb527b5a49e04a4345e61
Gitweb: https://git.kernel.org/tip/ad56450db86413ff911eb527b5a49e04a4345e61
Author: Boqun Feng <boqun.feng@gmail.com>
AuthorDate: Fri, 07 Aug 2020 15:42:37 +08:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 26 Aug 2020 12:42:07 +02:00
locking/selftest: Add test cases for queued_read_lock()
Add two self test cases for the following case:
P0: P1: P2:
<in irq handler>
spin_lock_irq(&slock) read_lock(&rwlock)
write_lock_irq(&rwlock)
read_lock(&rwlock) spin_lock(&slock)
, which is a deadlock, as the read_lock() on P0 cannot get the lock
because of the fairness.
P0: P1: P2:
<in irq handler>
spin_lock(&slock) read_lock(&rwlock)
write_lock(&rwlock)
read_lock(&rwlock) spin_lock_irq(&slock)
, which is not a deadlock, as the read_lock() on P0 can get the lock
because it could use the unfair fastpass.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-19-boqun.feng@gmail.com
---
lib/locking-selftest.c | 104 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 104 insertions(+)
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 4264cf4..17f8f6f 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -2201,6 +2201,108 @@ static void ww_tests(void)
pr_cont("\n");
}
+
+/*
+ * <in hardirq handler>
+ * read_lock(&A);
+ * <hardirq disable>
+ * spin_lock(&B);
+ * spin_lock(&B);
+ * read_lock(&A);
+ *
+ * is a deadlock.
+ */
+static void queued_read_lock_hardirq_RE_Er(void)
+{
+ HARDIRQ_ENTER();
+ read_lock(&rwlock_A);
+ LOCK(B);
+ UNLOCK(B);
+ read_unlock(&rwlock_A);
+ HARDIRQ_EXIT();
+
+ HARDIRQ_DISABLE();
+ LOCK(B);
+ read_lock(&rwlock_A);
+ read_unlock(&rwlock_A);
+ UNLOCK(B);
+ HARDIRQ_ENABLE();
+}
+
+/*
+ * <in hardirq handler>
+ * spin_lock(&B);
+ * <hardirq disable>
+ * read_lock(&A);
+ * read_lock(&A);
+ * spin_lock(&B);
+ *
+ * is not a deadlock.
+ */
+static void queued_read_lock_hardirq_ER_rE(void)
+{
+ HARDIRQ_ENTER();
+ LOCK(B);
+ read_lock(&rwlock_A);
+ read_unlock(&rwlock_A);
+ UNLOCK(B);
+ HARDIRQ_EXIT();
+
+ HARDIRQ_DISABLE();
+ read_lock(&rwlock_A);
+ LOCK(B);
+ UNLOCK(B);
+ read_unlock(&rwlock_A);
+ HARDIRQ_ENABLE();
+}
+
+/*
+ * <hardirq disable>
+ * spin_lock(&B);
+ * read_lock(&A);
+ * <in hardirq handler>
+ * spin_lock(&B);
+ * read_lock(&A);
+ *
+ * is a deadlock. Because the two read_lock()s are both non-recursive readers.
+ */
+static void queued_read_lock_hardirq_inversion(void)
+{
+
+ HARDIRQ_ENTER();
+ LOCK(B);
+ UNLOCK(B);
+ HARDIRQ_EXIT();
+
+ HARDIRQ_DISABLE();
+ LOCK(B);
+ read_lock(&rwlock_A);
+ read_unlock(&rwlock_A);
+ UNLOCK(B);
+ HARDIRQ_ENABLE();
+
+ read_lock(&rwlock_A);
+ read_unlock(&rwlock_A);
+}
+
+static void queued_read_lock_tests(void)
+{
+ printk(" --------------------------------------------------------------------------\n");
+ printk(" | queued read lock tests |\n");
+ printk(" ---------------------------\n");
+ print_testname("hardirq read-lock/lock-read");
+ dotest(queued_read_lock_hardirq_RE_Er, FAILURE, LOCKTYPE_RWLOCK);
+ pr_cont("\n");
+
+ print_testname("hardirq lock-read/read-lock");
+ dotest(queued_read_lock_hardirq_ER_rE, SUCCESS, LOCKTYPE_RWLOCK);
+ pr_cont("\n");
+
+ print_testname("hardirq inversion");
+ dotest(queued_read_lock_hardirq_inversion, FAILURE, LOCKTYPE_RWLOCK);
+ pr_cont("\n");
+}
+
void locking_selftest(void)
{
/*
@@ -2318,6 +2420,8 @@ void locking_selftest(void)
/*
* queued_read_lock() specific test cases can be put here
*/
+ if (IS_ENABLED(CONFIG_QUEUED_RWLOCKS))
+ queued_read_lock_tests();
if (unexpected_testcase_failures) {
printk("-----------------------------------------------------------------\n");
next prev parent reply other threads:[~2020-08-27 7:54 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-07 7:42 [RFC v7 00/19] lockdep: Support deadlock detection for recursive read locks Boqun Feng
2020-08-07 7:42 ` [RFC v7 01/19] locking: More accurate annotations for read_lock() Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 02/19] lockdep/Documention: Recursive read lock detection reasoning Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 03/19] lockdep: Demagic the return value of BFS Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 04/19] lockdep: Make __bfs() visit every dependency until a match Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 05/19] lockdep: Reduce the size of lock_list::distance Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 06/19] lockdep: Introduce lock_list::dep Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 07/19] lockdep: Extend __bfs() to work with multiple types of dependencies Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 08/19] lockdep: Make __bfs(.match) return bool Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 09/19] lockdep: Support deadlock detection for recursive read locks in check_noncircular() Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 10/19] lockdep: Adjust check_redundant() for recursive read change Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 11/19] lockdep: Fix recursive read lock related safe->unsafe detection Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-09-15 18:32 ` [RFC v7 11/19] " Qian Cai
2020-09-16 8:10 ` Boqun Feng
2020-09-16 16:14 ` Boqun Feng
2020-09-16 21:11 ` Qian Cai
2020-09-17 1:53 ` Boqun Feng
2020-08-07 7:42 ` [RFC v7 12/19] lockdep: Add recursive read locks into dependency graph Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-09-14 18:16 ` [RFC v7 12/19] " Qian Cai
2020-09-14 22:04 ` Qian Cai
2020-08-07 7:42 ` [RFC v7 13/19] lockdep/selftest: Add a R-L/L-W test case specific to chain cache behavior Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 14/19] lockdep: Take read/write status in consideration when generate chainkey Boqun Feng
2020-08-21 17:41 ` Peter Zijlstra
2020-08-22 2:52 ` boqun.feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 15/19] lockdep/selftest: Unleash irq_read_recursion2 and add more Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 16/19] lockdep/selftest: Add more recursive read related test cases Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 17/19] Revert "locking/lockdep/selftests: Fix mixed read-write ABBA tests" Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-07 7:42 ` [RFC v7 18/19] locking/selftest: Add test cases for queued_read_lock() Boqun Feng
2020-08-27 7:54 ` tip-bot2 for Boqun Feng [this message]
2020-08-07 7:42 ` [RFC v7 19/19] lockdep/selftest: Introduce recursion3 Boqun Feng
2020-08-27 7:54 ` [tip: locking/core] " tip-bot2 for Boqun Feng
2020-08-21 19:56 ` [RFC v7 00/19] lockdep: Support deadlock detection for recursive read locks Peter Zijlstra
2020-08-23 1:12 ` boqun.feng
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