diff options
| author | Jason Gunthorpe <jgg@nvidia.com> | 2020-11-23 16:50:59 -0400 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2020-11-23 16:50:59 -0400 |
| commit | ed92f6a52b84c0c03ae9d829cf118c6e38e456fb (patch) | |
| tree | 7b85d805aa96e8b89e8be80bd03c6e43b1e6db62 /kernel/locking/lockdep.c | |
| parent | df0e4de29c75fab2d59b67b7542ea1e10d32c6e1 (diff) | |
| parent | 418baf2c28f3473039f2f7377760bd8f6897ae18 (diff) | |
Merge tag 'v5.10-rc5' into rdma.git for-next
For dependencies in following patches
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'kernel/locking/lockdep.c')
| -rw-r--r-- | kernel/locking/lockdep.c | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index b71ad8d9f1c9..c1418b47f625 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -108,19 +108,21 @@ static inline void lockdep_lock(void) { DEBUG_LOCKS_WARN_ON(!irqs_disabled()); + __this_cpu_inc(lockdep_recursion); arch_spin_lock(&__lock); __owner = current; - __this_cpu_inc(lockdep_recursion); } static inline void lockdep_unlock(void) { + DEBUG_LOCKS_WARN_ON(!irqs_disabled()); + if (debug_locks && DEBUG_LOCKS_WARN_ON(__owner != current)) return; - __this_cpu_dec(lockdep_recursion); __owner = NULL; arch_spin_unlock(&__lock); + __this_cpu_dec(lockdep_recursion); } static inline bool lockdep_assert_locked(void) @@ -2765,7 +2767,9 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, * (Note that this has to be done separately, because the graph cannot * detect such classes of deadlocks.) * - * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read + * Returns: 0 on deadlock detected, 1 on OK, 2 if another lock with the same + * lock class is held but nest_lock is also held, i.e. we rely on the + * nest_lock to avoid the deadlock. */ static int check_deadlock(struct task_struct *curr, struct held_lock *next) @@ -2788,7 +2792,7 @@ check_deadlock(struct task_struct *curr, struct held_lock *next) * lock class (i.e. read_lock(lock)+read_lock(lock)): */ if ((next->read == 2) && prev->read) - return 2; + continue; /* * We're holding the nest_lock, which serializes this lock's @@ -3593,15 +3597,12 @@ static int validate_chain(struct task_struct *curr, if (!ret) return 0; /* - * Mark recursive read, as we jump over it when - * building dependencies (just like we jump over - * trylock entries): - */ - if (ret == 2) - hlock->read = 2; - /* * Add dependency only if this lock is not the head - * of the chain, and if it's not a secondary read-lock: + * of the chain, and if the new lock introduces no more + * lock dependency (because we already hold a lock with the + * same lock class) nor deadlock (because the nest_lock + * serializes nesting locks), see the comments for + * check_deadlock(). */ if (!chain_head && ret != 2) { if (!check_prevs_add(curr, hlock)) |