Commit-ID: 86cffb80a525f7b8f969c8c79669d383e02f17d1 Gitweb: https://git.kernel.org/tip/86cffb80a525f7b8f969c8c79669d383e02f17d1 Author: Bart Van Assche <bvanass...@acm.org> AuthorDate: Thu, 14 Feb 2019 15:00:41 -0800 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Thu, 28 Feb 2019 07:55:40 +0100
locking/lockdep: Make zap_class() remove all matching lock order entries Make sure that all lock order entries that refer to a class are removed from the list_entries[] array when a kernel module is unloaded. Signed-off-by: Bart Van Assche <bvanass...@acm.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Johannes Berg <johan...@sipsolutions.net> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Waiman Long <long...@redhat.com> Cc: Will Deacon <will.dea...@arm.com> Cc: johannes.b...@intel.com Cc: t...@kernel.org Link: https://lkml.kernel.org/r/20190214230058.196511-7-bvanass...@acm.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- include/linux/lockdep.h | 1 + kernel/locking/lockdep.c | 19 +++++++++++++------ 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 0c38bade84b7..b5e6bfe0ae4a 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -178,6 +178,7 @@ static inline void lockdep_copy_map(struct lockdep_map *to, struct lock_list { struct list_head entry; struct lock_class *class; + struct lock_class *links_to; struct stack_trace trace; int distance; diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index 21d84510e28f..28fbeb2a10cc 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -859,7 +859,8 @@ static struct lock_list *alloc_list_entry(void) /* * Add a new dependency to the head of the list: */ -static int add_lock_to_list(struct lock_class *this, struct list_head *head, +static int add_lock_to_list(struct lock_class *this, + struct lock_class *links_to, struct list_head *head, unsigned long ip, int distance, struct stack_trace *trace) { @@ -873,6 +874,7 @@ static int add_lock_to_list(struct lock_class *this, struct list_head *head, return 0; entry->class = this; + entry->links_to = links_to; entry->distance = distance; entry->trace = *trace; /* @@ -1907,14 +1909,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev, * Ok, all validations passed, add the new lock * to the previous lock's dependency list: */ - ret = add_lock_to_list(hlock_class(next), + ret = add_lock_to_list(hlock_class(next), hlock_class(prev), &hlock_class(prev)->locks_after, next->acquire_ip, distance, trace); if (!ret) return 0; - ret = add_lock_to_list(hlock_class(prev), + ret = add_lock_to_list(hlock_class(prev), hlock_class(next), &hlock_class(next)->locks_before, next->acquire_ip, distance, trace); if (!ret) @@ -4107,15 +4109,20 @@ void lockdep_reset(void) */ static void zap_class(struct lock_class *class) { + struct lock_list *entry; int i; /* * Remove all dependencies this lock is * involved in: */ - for (i = 0; i < nr_list_entries; i++) { - if (list_entries[i].class == class) - list_del_rcu(&list_entries[i].entry); + for (i = 0, entry = list_entries; i < nr_list_entries; i++, entry++) { + if (entry->class != class && entry->links_to != class) + continue; + list_del_rcu(&entry->entry); + /* Clear .class and .links_to to avoid double removal. */ + WRITE_ONCE(entry->class, NULL); + WRITE_ONCE(entry->links_to, NULL); } /* * Unhash the class and remove it from the all_lock_classes list:
