The following commit has been merged into the locking/core branch of tip: Commit-ID: 96a16f45aed89cf024606a11679b0609d09552c7 Gitweb: https://git.kernel.org/tip/96a16f45aed89cf024606a11679b0609d09552c7 Author: Boqun Feng <boqun.f...@gmail.com> AuthorDate: Fri, 07 Aug 2020 15:42:38 +08:00 Committer: Peter Zijlstra <pet...@infradead.org> CommitterDate: Wed, 26 Aug 2020 12:42:08 +02:00
lockdep/selftest: Introduce recursion3 Add a test case shows that USED_IN_*_READ and ENABLE_*_READ can cause deadlock too. Signed-off-by: Boqun Feng <boqun.f...@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Link: https://lkml.kernel.org/r/20200807074238.1632519-20-boqun.f...@gmail.com --- lib/locking-selftest.c | 55 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 55 insertions(+) diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 17f8f6f..a899b3f 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -1249,6 +1249,60 @@ GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft_rlock) #include "locking-selftest-wlock.h" GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion2_soft_wlock) +#undef E1 +#undef E2 +#undef E3 +/* + * read-lock / write-lock recursion that is unsafe. + * + * A is a ENABLED_*_READ lock + * B is a USED_IN_*_READ lock + * + * read_lock(A); + * write_lock(B); + * <interrupt> + * read_lock(B); + * write_lock(A); // if this one is read_lock(), no deadlock + */ + +#define E1() \ + \ + IRQ_DISABLE(); \ + WL(B); \ + LOCK(A); \ + UNLOCK(A); \ + WU(B); \ + IRQ_ENABLE(); + +#define E2() \ + \ + RL(A); \ + RU(A); \ + +#define E3() \ + \ + IRQ_ENTER(); \ + RL(B); \ + RU(B); \ + IRQ_EXIT(); + +/* + * Generate 24 testcases: + */ +#include "locking-selftest-hardirq.h" +#include "locking-selftest-rlock.h" +GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_hard_rlock) + +#include "locking-selftest-wlock.h" +GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_hard_wlock) + +#include "locking-selftest-softirq.h" +#include "locking-selftest-rlock.h" +GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_rlock) + +#include "locking-selftest-wlock.h" +GENERATE_PERMUTATIONS_3_EVENTS(irq_read_recursion3_soft_wlock) + #ifdef CONFIG_DEBUG_LOCK_ALLOC # define I_SPINLOCK(x) lockdep_reset_lock(&lock_##x.dep_map) # define I_RWLOCK(x) lockdep_reset_lock(&rwlock_##x.dep_map) @@ -2413,6 +2467,7 @@ void locking_selftest(void) DO_TESTCASE_6x2x2RW("irq read-recursion", irq_read_recursion); DO_TESTCASE_6x2x2RW("irq read-recursion #2", irq_read_recursion2); + DO_TESTCASE_6x2x2RW("irq read-recursion #3", irq_read_recursion3); ww_tests();
