linux-kernel - [PATCH 5.9 169/252] fail_function: Remove a redundant mutex unlock

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Date:   Mon, 23 Nov 2020 13:21:59 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hulk Robot <hulkci@...wei.com>,
        Luo Meng <luomeng12@...wei.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.9 169/252] fail_function: Remove a redundant mutex unlock

From: Luo Meng <luomeng12@...wei.com>

[ Upstream commit 2801a5da5b25b7af9dd2addd19b2315c02d17b64 ]

Fix a mutex_unlock() issue where before copy_from_user() is
not called mutex_locked.

Fixes: 4b1a29a7f542 ("error-injection: Support fault injection framework")
Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: Luo Meng <luomeng12@...wei.com>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
Signed-off-by: Alexei Starovoitov <ast@...nel.org>
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
Link: https://lore.kernel.org/bpf/160570737118.263807.8358435412898356284.stgit@devnote2
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 kernel/fail_function.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 63b349168da72..b0b1ad93fa957 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -253,7 +253,7 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 
 	if (copy_from_user(buf, buffer, count)) {
 		ret = -EFAULT;
-		goto out;
+		goto out_free;
 	}
 	buf[count] = '\0';
 	sym = strstrip(buf);
@@ -307,8 +307,9 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 		ret = count;
 	}
 out:
-	kfree(buf);
 	mutex_unlock(&fei_lock);
+out_free:
+	kfree(buf);
 	return ret;
 }
 
-- 
2.27.0