[PATCH] livepatch: RCU protect struct klp_func all the time when used in klp_ftrace_handler()

From: Petr Mladek
Date: Wed Feb 18 2015 - 12:01:29 EST

func->new_func has been accessed after rcu_read_unlock() in klp_ftrace_handler()
and therefore the access was not protected.

Signed-off-by: Petr Mladek <pmladek@xxxxxxx>
kernel/livepatch/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index ff7f47d026ac..cde66192e20e 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -314,12 +314,12 @@ static void notrace klp_ftrace_handler(unsigned long ip,
func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
- rcu_read_unlock();
if (WARN_ON_ONCE(!func))
- return;
+ goto unlock;

klp_arch_set_pc(regs, (unsigned long)func->new_func);
+ rcu_read_unlock();

static int klp_disable_func(struct klp_func *func)

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/