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author | Boqun Feng <boqun.feng@gmail.com> | 2020-08-07 10:42:32 +0300 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 13:42:06 +0300 |
commit | d4f200e579e96051f1f081f795820787826eb234 (patch) | |
tree | aa3051bc538092205afceffe8c9933e4b8da7a1a /lib/locking-selftest.c | |
parent | 621c9dac0eea7607cb9a57cc9ba47fbcd4e644c9 (diff) | |
download | linux-d4f200e579e96051f1f081f795820787826eb234.tar.xz |
lockdep/selftest: Add a R-L/L-W test case specific to chain cache behavior
As our chain cache doesn't differ read/write locks, so even we can
detect a read-lock/lock-write deadlock in check_noncircular(), we can
still be fooled if a read-lock/lock-read case(which is not a deadlock)
comes first.
So introduce this test case to test specific to the chain cache behavior
on detecting recursive read lock related deadlocks.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-14-boqun.feng@gmail.com
Diffstat (limited to 'lib/locking-selftest.c')
-rw-r--r-- | lib/locking-selftest.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index caadc4dd3368..002d1ec09852 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -400,6 +400,49 @@ static void rwsem_ABBA1(void) * read_lock(A) * spin_lock(B) * spin_lock(B) + * write_lock(A) + * + * This test case is aimed at poking whether the chain cache prevents us from + * detecting a read-lock/lock-write deadlock: if the chain cache doesn't differ + * read/write locks, the following case may happen + * + * { read_lock(A)->lock(B) dependency exists } + * + * P0: + * lock(B); + * read_lock(A); + * + * { Not a deadlock, B -> A is added in the chain cache } + * + * P1: + * lock(B); + * write_lock(A); + * + * { B->A found in chain cache, not reported as a deadlock } + * + */ +static void rlock_chaincache_ABBA1(void) +{ + RL(X1); + L(Y1); + U(Y1); + RU(X1); + + L(Y1); + RL(X1); + RU(X1); + U(Y1); + + L(Y1); + WL(X1); + WU(X1); + U(Y1); // should fail +} + +/* + * read_lock(A) + * spin_lock(B) + * spin_lock(B) * read_lock(A) */ static void rlock_ABBA2(void) @@ -2062,6 +2105,10 @@ void locking_selftest(void) pr_cont(" |"); dotest(rwsem_ABBA3, FAILURE, LOCKTYPE_RWSEM); + print_testname("chain cached mixed R-L/L-W ABBA"); + pr_cont(" |"); + dotest(rlock_chaincache_ABBA1, FAILURE, LOCKTYPE_RWLOCK); + printk(" --------------------------------------------------------------------------\n"); /* |