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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-04-23 13:20:57 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2013-08-18 17:40:03 -0700
commitae15018456c44b742d352af323e0b89eae4a6383 (patch)
tree784bd33ca97df210d581b59b9c3d8118ef057181 /kernel/rcu.h
parentb778ae25366e6f3891fe51306f56a3bca211975d (diff)
downloadop-kernel-dev-ae15018456c44b742d352af323e0b89eae4a6383.zip
op-kernel-dev-ae15018456c44b742d352af323e0b89eae4a6383.tar.gz
rcu: Make call_rcu() leak callbacks for debug-object errors
If someone does a duplicate call_rcu(), the worst thing the second call_rcu() could do would be to actually queue the callback the second time because doing so corrupts whatever list the callback was already queued on. This commit therefore makes __call_rcu() check the new return value from debug-objects and leak the callback upon error. This commit also substitutes rcu_leak_callback() for whatever callback function was previously in place in order to avoid freeing the callback out from under any readers that might still be referencing it. These changes increase the probability that the debug-objects error messages will actually make it somewhere visible. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Davidlohr Bueso <davidlohr.bueso@hp.com> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'kernel/rcu.h')
-rw-r--r--kernel/rcu.h10
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/rcu.h b/kernel/rcu.h
index 0a90ccc..7713196 100644
--- a/kernel/rcu.h
+++ b/kernel/rcu.h
@@ -67,12 +67,15 @@
extern struct debug_obj_descr rcuhead_debug_descr;
-static inline void debug_rcu_head_queue(struct rcu_head *head)
+static inline int debug_rcu_head_queue(struct rcu_head *head)
{
- debug_object_activate(head, &rcuhead_debug_descr);
+ int r1;
+
+ r1 = debug_object_activate(head, &rcuhead_debug_descr);
debug_object_active_state(head, &rcuhead_debug_descr,
STATE_RCU_HEAD_READY,
STATE_RCU_HEAD_QUEUED);
+ return r1;
}
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
@@ -83,8 +86,9 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
debug_object_deactivate(head, &rcuhead_debug_descr);
}
#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
-static inline void debug_rcu_head_queue(struct rcu_head *head)
+static inline int debug_rcu_head_queue(struct rcu_head *head)
{
+ return 0;
}
static inline void debug_rcu_head_unqueue(struct rcu_head *head)
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