Simplify ftrace_hash_disable/enable path in ftrace_hash_move
for hardening the process if the memory allocation failed.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Josh Poimboeuf <jpoim...@redhat.com>
---
kernel/trace/ftrace.c | 33 +++++++++++----------------------
1 file changed, 11 insertions(+), 22 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index cc07b7f..e355b60 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1304,25 +1304,15 @@ 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;
}
/*
@@ -1335,10 +1325,9 @@ 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++) {
@@ -1349,20 +1338,20 @@ 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;
}
/*
--
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