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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-06-19 14:57:10 -0700 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-06-23 11:19:29 -0700 |
commit | 546a9d8519ed137b2804a3f5a3659003039dd49c (patch) | |
tree | 1f4c679c28b2980e08bc1d0bb8c0b01dc6d98247 | |
parent | 7171511eaec5bf23fb06078f59784a3a0626b38f (diff) | |
download | op-kernel-dev-546a9d8519ed137b2804a3f5a3659003039dd49c.zip op-kernel-dev-546a9d8519ed137b2804a3f5a3659003039dd49c.tar.gz |
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@oracle.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Looks-good-to: Christoph Lameter <cl@linux.com>
-rw-r--r-- | include/linux/rcupdate.h | 10 | ||||
-rw-r--r-- | 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); } |