uprobes: Introduce free_ret_instance()
We can simplify uprobe_free_utask() and handle_uretprobe_chain()
if we add a simple helper which does put_uprobe/kfree and
returns the ->next return_instance.
Tested-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Anton Arapov <arapov@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150721134006.GA4740@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index a9847b4..d8c702f 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -1378,6 +1378,14 @@
return instruction_pointer(regs);
}
+static struct return_instance *free_ret_instance(struct return_instance *ri)
+{
+ struct return_instance *next = ri->next;
+ put_uprobe(ri->uprobe);
+ kfree(ri);
+ return next;
+}
+
/*
* Called with no locks held.
* Called in context of a exiting or a exec-ing thread.
@@ -1385,7 +1393,7 @@
void uprobe_free_utask(struct task_struct *t)
{
struct uprobe_task *utask = t->utask;
- struct return_instance *ri, *tmp;
+ struct return_instance *ri;
if (!utask)
return;
@@ -1394,13 +1402,8 @@
put_uprobe(utask->active_uprobe);
ri = utask->return_instances;
- while (ri) {
- tmp = ri;
- ri = ri->next;
-
- put_uprobe(tmp->uprobe);
- kfree(tmp);
- }
+ while (ri)
+ ri = free_ret_instance(ri);
xol_free_insn_slot(t);
kfree(utask);
@@ -1770,7 +1773,7 @@
static bool handle_trampoline(struct pt_regs *regs)
{
struct uprobe_task *utask;
- struct return_instance *ri, *tmp;
+ struct return_instance *ri;
bool chained;
utask = current->utask;
@@ -1792,11 +1795,7 @@
handle_uretprobe_chain(ri, regs);
chained = ri->chained;
- put_uprobe(ri->uprobe);
-
- tmp = ri;
- ri = ri->next;
- kfree(tmp);
+ ri = free_ret_instance(ri);
utask->depth--;
if (!chained)