Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 5c27c775 authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt
Browse files

ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move 

Simplify ftrace_hash_disable/enable path in ftrace_hash_move
for hardening the process if the memory allocation failed.

Link: http://lkml.kernel.org/p/20140617110442.15167.81076.stgit@kbuild-fedora.novalocal



Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent d8fae2f6

kernel/trace/ftrace.c

+11 −22
Original line number Diff line number Diff line
@@ -1306,25 +1306,15 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, 
	struct ftrace_hash *new_hash;

	int size = src->count;

	int bits = 0;

	int ret;

	int i;



	/*

	 * Remove the current set, update the hash and add

	 * them back.

	 */

	ftrace_hash_rec_disable(ops, enable);



	/*

	 * If the new source is empty, just free dst and assign it

	 * the empty_hash.

	 */

	if (!src->count) {

		free_ftrace_hash_rcu(*dst);

		rcu_assign_pointer(*dst, EMPTY_HASH);

		/* still need to update the function records */

		ret = 0;

		goto out;

		new_hash = EMPTY_HASH;

		goto update;

	}



	/*
@@ -1337,10 +1327,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, 
	if (bits > FTRACE_HASH_MAX_BITS)

		bits = FTRACE_HASH_MAX_BITS;



	ret = -ENOMEM;

	new_hash = alloc_ftrace_hash(bits);

	if (!new_hash)

		goto out;

		return -ENOMEM;



	size = 1 << src->size_bits;

	for (i = 0; i < size; i++) {
@@ -1351,20 +1340,20 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, 
		}

	}



update:

	/*

	 * Remove the current set, update the hash and add

	 * them back.

	 */

	ftrace_hash_rec_disable(ops, enable);



	old_hash = *dst;

	rcu_assign_pointer(*dst, new_hash);

	free_ftrace_hash_rcu(old_hash);



	ret = 0;

 out:

	/*

	 * Enable regardless of ret:

	 *  On success, we enable the new hash.

	 *  On failure, we re-enable the original hash.

	 */

	ftrace_hash_rec_enable(ops, enable);



	return ret;

	return 0;

}



/*