From: Pavel Andrianov <andrianov@ispras.ru>
Date: Mon, 5 Sep 2016 13:17:47 +0000 (+0300)
Subject: speakup: Add spinlock in synth_direct_store
X-Git-Tag: v4.9-rc1~119^2~659
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=777953182ea9a750e744bd0a50fb8893cd061397;p=karo-tx-linux.git

speakup: Add spinlock in synth_direct_store

All operations with synth buffer should be protected,
as there are global pointers, which should be modified atomically.

Found by Linux Driver Verification project (linuxtesting.org)

Signed-off-by: Pavel Andrianov <andrianov@ispras.ru>
Acked-by: Vaishali Thakkar <vaishali.thakkar@oracle.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/staging/speakup/kobjects.c b/drivers/staging/speakup/kobjects.c
index 528cbdce4227..7fedee363455 100644
--- a/drivers/staging/speakup/kobjects.c
+++ b/drivers/staging/speakup/kobjects.c
@@ -411,11 +411,13 @@ static ssize_t synth_direct_store(struct kobject *kobj,
 	int len;
 	int bytes;
 	const char *ptr = buf;
+	unsigned long flags;
 
 	if (!synth)
 		return -EPERM;
 
 	len = strlen(buf);
+	spin_lock_irqsave(&speakup_info.spinlock, flags);
 	while (len > 0) {
 		bytes = min_t(size_t, len, 250);
 		strncpy(tmp, ptr, bytes);
@@ -425,6 +427,7 @@ static ssize_t synth_direct_store(struct kobject *kobj,
 		ptr += bytes;
 		len -= bytes;
 	}
+	spin_unlock_irqrestore(&speakup_info.spinlock, flags);
 	return count;
 }