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Commit 2bb5e840 authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Ingo Molnar
Browse files

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: default avatarPratyush Anand <panand@redhat.com>
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarAnton 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: default avatarIngo Molnar <mingo@kernel.org>
parent f231722a

kernel/events/uprobes.c

+13 −14
Original line number Diff line number Diff line
@@ -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)