From: Boqun Feng <boqun.feng@gmail.com> To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>, Andrea Parri <parri.andrea@gmail.com>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Boqun Feng <boqun.feng@gmail.com> Subject: [RFC tip/locking/lockdep v6 13/20] lockdep/selftest: Add a R-L/L-W test case specific to chain cache behavior Date: Wed, 11 Apr 2018 21:51:03 +0800 [thread overview] Message-ID: <20180411135110.9217-14-boqun.feng@gmail.com> (raw) In-Reply-To: <20180411135110.9217-1-boqun.feng@gmail.com> 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> --- lib/locking-selftest.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index b5c1293ce147..700f9aa19db6 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -395,6 +395,49 @@ static void rwsem_ABBA1(void) MU(Y1); // should fail } +/* + * 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) @@ -2055,6 +2098,10 @@ 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"); /* -- 2.16.2
next prev parent reply other threads:[~2018-04-11 13:48 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-04-11 13:50 [RFC tip/locking/lockdep v6 00/20] lockdep: Support deadlock detection for recursive read locks Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 01/20] lockdep/Documention: Recursive read lock detection reasoning Boqun Feng 2018-04-15 0:38 ` Randy Dunlap 2018-04-16 6:29 ` Boqun Feng 2018-04-27 13:50 ` Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 02/20] lockdep: Demagic the return value of BFS Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 03/20] lockdep: Make __bfs() visit every dependency until a match Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 04/20] lockdep: Redefine LOCK_*_STATE* bits Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 05/20] lockdep: Reduce the size of lock_list::distance Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 06/20] lockdep: Introduce lock_list::dep Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 07/20] lockdep: Extend __bfs() to work with multiple types of dependencies Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 08/20] lockdep: Make __bfs(.match) return bool Boqun Feng 2018-04-11 13:50 ` [RFC tip/locking/lockdep v6 09/20] lockdep: Support deadlock detection for recursive read locks in check_noncircular() Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 10/20] lockdep: Adjust check_redundant() for recursive read change Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 11/20] lockdep: Fix recursive read lock related safe->unsafe detection Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 12/20] lockdep: Add recursive read locks into dependency graph Boqun Feng 2018-04-11 13:51 ` Boqun Feng [this message] 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 14/20] lockdep: Take read/write status in consideration when generate chainkey Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 15/20] lockdep/selftest: Unleash irq_read_recursion2 and add more Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 16/20] lockdep/selftest: Add more recursive read related test cases Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 17/20] Revert "locking/lockdep/selftests: Fix mixed read-write ABBA tests" Boqun Feng 2018-04-11 13:51 ` [RFC tip/locking/lockdep v6 18/20] MAINTAINERS: Add myself as a LOCKING PRIMITIVES reviewer Boqun Feng 2018-04-11 13:56 ` [RFC tip/locking/lockdep v6 19/20] rcu: Equip sleepable RCU with lockdep dependency graph checks Boqun Feng 2018-04-11 18:57 ` Paul E. McKenney 2018-04-12 2:12 ` Boqun Feng 2018-04-12 9:12 ` Peter Zijlstra 2018-04-13 13:24 ` Boqun Feng 2018-04-11 13:57 ` [RFC tip/locking/lockdep v6 20/20] lockdep/selftest: Add a test case for SRCU Boqun Feng
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