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authorBoqun Feng <boqun.feng@gmail.com>2020-11-02 13:37:42 +0800
committerPeter Zijlstra <peterz@infradead.org>2020-12-03 11:20:50 +0100
commite04ce676e7aa490dcf5df880592e3db5e842a9bc (patch)
treeff5ed969437455675e570795708e4e0357eab7c2 /lib/locking-selftest.c
parenta2e9ae58d5042b3aa4a61f676ff6975ff3bc7bc7 (diff)
downloadlinux-e04ce676e7aa490dcf5df880592e3db5e842a9bc.tar.bz2
lockdep/selftest: Add spin_nest_lock test
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> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20201102053743.450459-2-boqun.feng@gmail.com
Diffstat (limited to 'lib/locking-selftest.c')
-rw-r--r--lib/locking-selftest.c17
1 files changed, 17 insertions, 0 deletions
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");