diff options
| author | Boqun Feng <boqun.feng@gmail.com> | 2020-08-07 15:42:20 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-08-26 12:42:02 +0200 |
| commit | e918188611f073063415f40fae568fa4d86d9044 (patch) | |
| tree | 360f04ba1aeae14a4205a2b74ce0f5090bf70378 /include/linux/lockdep.h | |
| parent | 92b4e9f11a636d1723cc0866bf8b9111b1e24339 (diff) | |
locking: More accurate annotations for read_lock()
On the archs using QUEUED_RWLOCKS, read_lock() is not always a recursive
read lock, actually it's only recursive if in_interrupt() is true. So
change the annotation accordingly to catch more deadlocks.
Note we used to treat read_lock() as pure recursive read locks in
lib/locking-seftest.c, and this is useful, especially for the lockdep
development selftest, so we keep this via a variable to force switching
lock annotation for read_lock().
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200807074238.1632519-2-boqun.feng@gmail.com
Diffstat (limited to 'include/linux/lockdep.h')
| -rw-r--r-- | include/linux/lockdep.h | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 6a584b3e5c74..7cae5ea00d59 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -469,6 +469,20 @@ static inline void print_irqtrace_events(struct task_struct *curr) } #endif +/* Variable used to make lockdep treat read_lock() as recursive in selftests */ +#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS +extern unsigned int force_read_lock_recursive; +#else /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */ +#define force_read_lock_recursive 0 +#endif /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */ + +#ifdef CONFIG_LOCKDEP +extern bool read_lock_is_recursive(void); +#else /* CONFIG_LOCKDEP */ +/* If !LOCKDEP, the value is meaningless */ +#define read_lock_is_recursive() 0 +#endif + /* * For trivial one-depth nesting of a lock-class, the following * global define can be used. (Subsystems with multiple levels @@ -490,7 +504,14 @@ static inline void print_irqtrace_events(struct task_struct *curr) #define spin_release(l, i) lock_release(l, i) #define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) -#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i) +#define rwlock_acquire_read(l, s, t, i) \ +do { \ + if (read_lock_is_recursive()) \ + lock_acquire_shared_recursive(l, s, t, NULL, i); \ + else \ + lock_acquire_shared(l, s, t, NULL, i); \ +} while (0) + #define rwlock_release(l, i) lock_release(l, i) #define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i) |