From: Steven Rostedt (VMware) <rostedt@goodmis.org>
Date: Fri, 15 Nov 2019 19:19:04 +0000 (-0500)
Subject: ftrace: Add another check for match in register_ftrace_direct()
X-Git-Tag: v5.5-rc1~130^2~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=406acdd32d3e7d5a6dcb7f67798e89068fbe0d77;p=thirdparty%2Fkernel%2Flinux.git

ftrace: Add another check for match in register_ftrace_direct()

As an instruction pointer passed into register_ftrace_direct() may just
exist on the ftrace call site, but may not be the start of the call site
itself, register_ftrace_direct() still needs to update test if a direct call
exists on the normalized site, as only one direct call is allowed at any one
time.

Fixes: 763e34e74bb7d ("ftrace: Add register_ftrace_direct()")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 32e4e5ffdd974..9fe33ebaf9147 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5030,7 +5030,12 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
 		goto out_unlock;
 
 	/* Make sure the ip points to the exact record */
-	ip = rec->ip;
+	if (ip != rec->ip) {
+		ip = rec->ip;
+		/* Need to check this ip for a direct. */
+		if (find_rec_direct(ip))
+			goto out_unlock;
+	}
 
 	ret = -ENOMEM;
 	if (ftrace_hash_empty(direct_functions) ||