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ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move

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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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu 2014-06-17 11:04:42 +00:00 committed by Steven Rostedt
parent d8fae2f644
commit 5c27c775d5
1 changed files with 11 additions and 22 deletions
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33
kernel/trace/ftrace.c
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@ -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;
}
/*