On 08/11, Oleg Nesterov wrote:
>
> I'll send another debugging patch tomorrow, I was a bit busy today. The next
> step is obvious, we need to know the caller.
Please drop two patches I sent before anf try the new one below.
Which kernel version do you use?
Oleg.
---
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index e5a3244..533da3ab 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -711,6 +711,15 @@ static inline int page_has_private(struct page *page)
return !!(page->flags & PAGE_FLAGS_PRIVATE);
}
+void unlock_page_x(struct page *page);
+static inline void __ClearPageLocked_x(struct page *page)
+{
+ if (PageLocked(compound_head(page)))
+ unlock_page_x(page);
+}
+
+#define __ClearPageLocked(page) __ClearPageLocked_x(page)
+
#undef PF_ANY
#undef PF_HEAD
#undef PF_NO_TAIL
diff --git a/mm/filemap.c b/mm/filemap.c
index 20f3b1f..fb320fb 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -837,6 +837,43 @@ void unlock_page(struct page *page)
}
EXPORT_SYMBOL(unlock_page);
+void unlock_page_x(struct page *__page)
+{
+ struct page *page = compound_head(__page);
+ wait_queue_head_t *wq = page_waitqueue(page);
+ struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(&page->flags,
PG_locked);
+ wait_queue_t *curr, *next;
+ unsigned long flags;
+ bool w = false;
+
+ #define W() do {
\
+ if (!w) { w = true; pr_crit("XXXXXXXXXXXX\n"); dump_stack(); }
\
+ } while (0)
+
+ clear_bit_unlock(PG_locked, &page->flags);
+ smp_mb__after_atomic();
+
+ if (!waitqueue_active(wq))
+ return;
+
+ spin_lock_irqsave(&wq->lock, flags);
+ list_for_each_entry_safe(curr, next, &wq->task_list, task_list) {
+ if (curr->func == wake_bit_function) {
+ struct wait_bit_queue *wb = container_of(curr, struct
wait_bit_queue, wait);
+ if (wb->key.flags == key.flags && wb->key.bit_nr ==
PG_locked) {
+ W();
+ pr_crit("XXX flags = %x, waiter:\n",
curr->flags);
+ sched_show_task(curr->private);
+ }
+ } else {
+ W();
+ pr_crit("XXX flags = %x, func = %pF\n", curr->flags,
curr->func);
+ }
+ curr->func(curr, TASK_NORMAL, 0, &key);
+ }
+ spin_unlock_irqrestore(&wq->lock, flags);
+}
+
/**
* end_page_writeback - end writeback against a page
* @page: the page
