Commit-ID: 546a9d8519ed137b2804a3f5a3659003039dd49c
Gitweb: http://git.kernel.org/tip/546a9d8519ed137b2804a3f5a3659003039dd49c
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Thu, 19 Jun 2014 14:57:10 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 23 Jun 2014 11:19:29 -0700
rcu: Export debug_init_rcu_head() and and debug_init_rcu_head()
Currently, call_rcu() relies on implicit allocation and initialization
for the debug-objects handling of RCU callbacks. If you hammer the
kernel hard enough with Sasha's modified version of trinity, you can end
up with the sl*b allocators recursing into themselves via this implicit
call_rcu() allocation.
This commit therefore exports the debug_init_rcu_head() and
debug_rcu_head_free() functions, which permits the allocators to allocated
and pre-initialize the debug-objects information, so that there no longer
any need for call_rcu() to do that initialization, which in turn prevents
the recursion into the memory allocators.
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Suggested-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Looks-good-to: Christoph Lameter <cl@xxxxxxxxx>
---
include/linux/rcupdate.h | 10 ++++++++++
kernel/rcu/update.c | 4 ++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 5a75d19..13bbfbd 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -358,9 +358,19 @@ void wait_rcu_gp(call_rcu_func_t crf);
* initialization.
*/
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+void init_rcu_head(struct rcu_head *head);
+void destroy_rcu_head(struct rcu_head *head);
void init_rcu_head_on_stack(struct rcu_head *head);
void destroy_rcu_head_on_stack(struct rcu_head *head);
#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+static inline void init_rcu_head(struct rcu_head *head)
+{
+}
+
+static inline void destroy_rcu_head(struct rcu_head *head)
+{
+}
+
static inline void init_rcu_head_on_stack(struct rcu_head *head)
{
}
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index a2aeb4d..0fb691e 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -200,12 +200,12 @@ void wait_rcu_gp(call_rcu_func_t crf)
EXPORT_SYMBOL_GPL(wait_rcu_gp);
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
-static inline void debug_init_rcu_head(struct rcu_head *head)
+void init_rcu_head(struct rcu_head *head)
{
debug_object_init(head, &rcuhead_debug_descr);
}
-static inline void debug_rcu_head_free(struct rcu_head *head)
+void destroy_rcu_head(struct rcu_head *head)
{
debug_object_free(head, &rcuhead_debug_descr);
}
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|