Commit 9a98e03c authored by Oleg Nesterov's avatar Oleg Nesterov
Browse files

uprobes: _register() should always do register_for_each_vma(true) 



To support the filtering uprobe_register() should do
register_for_each_vma(true) every time the new consumer comes,
we need to install the previously nacked breakpoints.

Note:
	- uprobes_mutex[] should die, what it actually protects is
	  alloc_uprobe().

	- UPROBE_RUN_HANDLER should die too, obviously it can't work
	  unless uprobe has a single consumer. The consumer should
	  serialize with _register/_unregister itself. Or this flag
	  should live in uprobe_consumer->state.

	- Perhaps we can do some optimizations later. For example, if
	  filter_chain() never returns false uprobe can record this
	  fact and avoid the unnecessary register_for_each_vma().

Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
parent 04aab9b2

kernel/events/uprobes.c

+13 −18
Original line number Diff line number Diff line
@@ -482,16 +482,12 @@ static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) 
	up_read(&uprobe->consumer_rwsem);

}



/* Returns the previous consumer */

static struct uprobe_consumer *

consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)

static void consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)

{

	down_write(&uprobe->consumer_rwsem);

	uc->next = uprobe->consumers;

	uprobe->consumers = uc;

	up_write(&uprobe->consumer_rwsem);



	return uc->next;

}



/*
@@ -820,9 +816,15 @@ static int register_for_each_vma(struct uprobe *uprobe, bool is_register) 
	return err;

}



static int __uprobe_register(struct uprobe *uprobe)

static int __uprobe_register(struct uprobe *uprobe, struct uprobe_consumer *uc)

{

	return register_for_each_vma(uprobe, true);

	int err;



	consumer_add(uprobe, uc);

	err = register_for_each_vma(uprobe, true);

	if (!err) /* TODO: pointless unless the first consumer */

		set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);

	return err;

}



static void __uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
@@ -867,21 +869,14 @@ int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer * 
	if (offset > i_size_read(inode))

		return -EINVAL;



	ret = 0;

	ret = -ENOMEM;

	mutex_lock(uprobes_hash(inode));

	uprobe = alloc_uprobe(inode, offset);



	if (!uprobe) {

		ret = -ENOMEM;

	} else if (!consumer_add(uprobe, uc)) {

		ret = __uprobe_register(uprobe);

		if (ret) {

	if (uprobe) {

		ret = __uprobe_register(uprobe, uc);

		if (ret)

			__uprobe_unregister(uprobe, uc);

		} else {

			set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);

		}

	}



	mutex_unlock(uprobes_hash(inode));

	if (uprobe)

		put_uprobe(uprobe);

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