Commit-ID: e91498589746065e3ae95d9a00b068e525eec34f
Gitweb: http://git.kernel.org/tip/e91498589746065e3ae95d9a00b068e525eec34f
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Wed, 23 Aug 2017 13:13:11 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 25 Aug 2017 11:06:31 +0200
locking/lockdep/selftests: Add mixed read-write ABBA tests
Currently lockdep has limited support for recursive readers, add a few
mixed read-write ABBA selftests to show the extend of these
limitations.
[ 0.000000] ----------------------------------------------------------------------------
[ 0.000000] | spin |wlock |rlock |mutex | wsem | rsem |
[ 0.000000] --------------------------------------------------------------------------
[ 0.000000] mixed read-lock/lock-write ABBA: |FAILED| | ok |
[ 0.000000] mixed read-lock/lock-read ABBA: | ok | | ok |
[ 0.000000] mixed write-lock/lock-write ABBA: | ok | | ok |
This clearly illustrates the case where lockdep fails to find a
deadlock.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: boqun.feng@xxxxxxxxx
Cc: byungchul.park@xxxxxxx
Cc: david@xxxxxxxxxxxxx
Cc: johannes@xxxxxxxxxxxxxxxx
Cc: oleg@xxxxxxxxxx
Cc: tj@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
lib/locking-selftest.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 115 insertions(+), 2 deletions(-)
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 6f2b135..3c7151a 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -363,6 +363,103 @@ static void rsem_AA3(void)
}
/*
+ * read_lock(A)
+ * spin_lock(B)
+ * spin_lock(B)
+ * write_lock(A)
+ */
+static void rlock_ABBA1(void)
+{
+ RL(X1);
+ L(Y1);
+ U(Y1);
+ RU(X1);
+
+ L(Y1);
+ WL(X1);
+ WU(X1);
+ U(Y1); // should fail
+}
+
+static void rwsem_ABBA1(void)
+{
+ RSL(X1);
+ ML(Y1);
+ MU(Y1);
+ RSU(X1);
+
+ ML(Y1);
+ WSL(X1);
+ WSU(X1);
+ MU(Y1); // should fail
+}
+
+/*
+ * read_lock(A)
+ * spin_lock(B)
+ * spin_lock(B)
+ * read_lock(A)
+ */
+static void rlock_ABBA2(void)
+{
+ RL(X1);
+ L(Y1);
+ U(Y1);
+ RU(X1);
+
+ L(Y1);
+ RL(X1);
+ RU(X1);
+ U(Y1); // should NOT fail
+}
+
+static void rwsem_ABBA2(void)
+{
+ RSL(X1);
+ ML(Y1);
+ MU(Y1);
+ RSU(X1);
+
+ ML(Y1);
+ RSL(X1);
+ RSU(X1);
+ MU(Y1); // should fail
+}
+
+
+/*
+ * write_lock(A)
+ * spin_lock(B)
+ * spin_lock(B)
+ * write_lock(A)
+ */
+static void rlock_ABBA3(void)
+{
+ WL(X1);
+ L(Y1);
+ U(Y1);
+ WU(X1);
+
+ L(Y1);
+ WL(X1);
+ WU(X1);
+ U(Y1); // should fail
+}
+
+static void rwsem_ABBA3(void)
+{
+ WSL(X1);
+ ML(Y1);
+ MU(Y1);
+ WSU(X1);
+
+ ML(Y1);
+ WSL(X1);
+ WSU(X1);
+ MU(Y1); // should fail
+}
+
+/*
* ABBA deadlock:
*/
@@ -1056,8 +1153,6 @@ static void dotest(void (*testcase_fn)(void), int expected, int lockclass_mask)
if (debug_locks != expected) {
unexpected_testcase_failures++;
pr_cont("FAILED|");
-
- dump_stack();
} else {
testcase_successes++;
pr_cont(" ok |");
@@ -1933,6 +2028,24 @@ void locking_selftest(void)
dotest(rsem_AA3, FAILURE, LOCKTYPE_RWSEM);
pr_cont("\n");
+ print_testname("mixed read-lock/lock-write ABBA");
+ pr_cont(" |");
+ dotest(rlock_ABBA1, FAILURE, LOCKTYPE_RWLOCK);
+ pr_cont(" |");
+ dotest(rwsem_ABBA1, FAILURE, LOCKTYPE_RWSEM);
+
+ print_testname("mixed read-lock/lock-read ABBA");
+ pr_cont(" |");
+ dotest(rlock_ABBA2, SUCCESS, LOCKTYPE_RWLOCK);
+ pr_cont(" |");
+ dotest(rwsem_ABBA2, FAILURE, LOCKTYPE_RWSEM);
+
+ print_testname("mixed write-lock/lock-write ABBA");
+ pr_cont(" |");
+ dotest(rlock_ABBA3, FAILURE, LOCKTYPE_RWLOCK);
+ pr_cont(" |");
+ dotest(rwsem_ABBA3, FAILURE, LOCKTYPE_RWSEM);
+
printk(" --------------------------------------------------------------------------\n");
/*
--
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