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>
This commit is contained in:
Oleg Nesterov 2015-07-21 15:40:06 +02:00 committed by Ingo Molnar
parent f231722a2b
commit 2bb5e840e8

View file

@ -1378,6 +1378,14 @@ unsigned long uprobe_get_trap_addr(struct pt_regs *regs)
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 @@ unsigned long uprobe_get_trap_addr(struct pt_regs *regs)
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 @@ void uprobe_free_utask(struct task_struct *t)
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 @@ handle_uretprobe_chain(struct return_instance *ri, struct pt_regs *regs)
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 @@ static bool handle_trampoline(struct pt_regs *regs)
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)