From: Shuah Khan <sk...@linuxfoundation.org> Some kernel functions must be called without holding a specific lock. Add lockdep_assert_not_held() to be used in these functions to detect incorrect calls while holding a lock.
lockdep_assert_not_held() provides the opposite functionality of lockdep_assert_held() which is used to assert calls that require holding a specific lock. Incorporates suggestions from Peter Zijlstra to avoid misfires when lockdep_off() is employed. The need for lockdep_assert_not_held() came up in a discussion on ath10k patch. ath10k_drain_tx() and i915_vma_pin_ww() are examples of functions that can use lockdep_assert_not_held(). Signed-off-by: Shuah Khan <sk...@linuxfoundation.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Ingo Molnar <mi...@kernel.org> Link: https://lore.kernel.org/linux-wireless/871rdmu9z9....@codeaurora.org/ (cherry picked from ms commit 3e31f94752e454bdd0ca4a1d046ee21f80c166c5) Signed-off-by: Konstantin Khorenko <khore...@virtuozzo.com> --- include/linux/lockdep.h | 9 +++++++-- kernel/lockdep.c | 6 +++++- 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 242f69bddecf..1aff47ff71fd 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -367,8 +367,12 @@ extern void lockdep_trace_alloc(gfp_t mask); #define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0) -#define lockdep_assert_held(l) do { \ - WARN_ON(debug_locks && !lockdep_is_held(l)); \ +#define lockdep_assert_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 0); \ + } while (0) + +#define lockdep_assert_not_held(l) do { \ + WARN_ON(debug_locks && lockdep_is_held(l) == 1); \ } while (0) #define lockdep_assert_held_exclusive(l) do { \ @@ -435,6 +439,7 @@ struct lock_class_key { }; #define lockdep_is_held_type(l, r) (1) #define lockdep_assert_held(l) do { (void)(l); } while (0) +#define lockdep_assert_not_held(l) do { (void)(l); } while (0) #define lockdep_assert_held_exclusive(l) do { (void)(l); } while (0) #define lockdep_assert_held_read(l) do { (void)(l); } while (0) #define lockdep_assert_held_once(l) do { (void)(l); } while (0) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 856b3d37c965..cdb82f1ce49a 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -3657,8 +3657,12 @@ int lock_is_held_type(struct lockdep_map *lock, int read) unsigned long flags; int ret = 0; + /* + * Avoid false negative lockdep_assert_held() and + * lockdep_assert_not_held(). + */ if (unlikely(current->lockdep_recursion)) - return 1; /* avoid false negative lockdep_assert_held() */ + return -1; raw_local_irq_save(flags); check_flags(flags); -- 2.24.3 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
