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| author | Boqun Feng <boqun.feng@gmail.com> | 2020-08-07 15:42:38 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 12:42:08 +0200 |
| commit | 96a16f45aed89cf024606a11679b0609d09552c7 (patch) | |
| tree | fb9512b7b6a73bb1e5c1ffe6167376ffac104b4c | |
| parent | ad56450db86413ff911eb527b5a49e04a4345e61 (diff) | |
| download | lwn-96a16f45aed89cf024606a11679b0609d09552c7.tar.gz lwn-96a16f45aed89cf024606a11679b0609d09552c7.zip | |
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.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-20-boqun.feng@gmail.com
| -rw-r--r-- | lib/locking-selftest.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 17f8f6f37165..a899b3f0e2e5 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(); |