From 673d62cc5ea6fca046650f17f77985b112c62322 Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Sun, 31 Aug 2008 23:39:21 +0200 Subject: debugobjects: fix lockdep warning Daniel J. Blueman reported: > ======================================================= > [ INFO: possible circular locking dependency detected ] > 2.6.27-rc4-224c #1 > ------------------------------------------------------- > hald/4680 is trying to acquire lock: > (&n->list_lock){++..}, at: [] add_partial+0x26/0x80 > > but task is already holding lock: > (&obj_hash[i].lock){++..}, at: [] > debug_object_free+0x5c/0x120 We fix it by moving the actual freeing to outside the lock (the lock now only protects the list). The pool lock is also promoted to irq-safe (suggested by Dan). It's necessary because free_pool is now called outside the irq disabled region. So we need to protect against an interrupt handler which calls debug_object_init(). [tglx@linutronix.de: added hlist_move_list helper to avoid looping through the list twice] Reported-by: Daniel J Blueman Signed-off-by: Vegard Nossum Signed-off-by: Thomas Gleixner --- include/linux/list.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/list.h b/include/linux/list.h index db35ef02e74..969f6e92d08 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -619,6 +619,19 @@ static inline void hlist_add_after(struct hlist_node *n, next->next->pprev = &next->next; } +/* + * Move a list from one list head to another. Fixup the pprev + * reference of the first entry if it exists. + */ +static inline void hlist_move_list(struct hlist_head *old, + struct hlist_head *new) +{ + new->first = old->first; + if (new->first) + new->first->pprev = &new->first; + old->first = NULL; +} + #define hlist_entry(ptr, type, member) container_of(ptr,type,member) #define hlist_for_each(pos, head) \ -- cgit v1.2.3