linux-kernel - [PATCH] speakup: Add spinlock in synth_direct

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Message-Id: <1473081467-1892-1-git-send-email-andrianov@ispras.ru>
Date:   Mon,  5 Sep 2016 16:17:47 +0300
From:   Pavel Andrianov <andrianov@...ras.ru>
To:     Samuel Thibault <samuel.thibault@...-lyon.org>
Cc:     Pavel Andrianov <andrianov@...ras.ru>,
        William Hubbs <w.d.hubbs@...il.com>,
        Chris Brannon <chris@...-brannons.com>,
        Kirk Reiser <kirk@...sers.ca>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Shraddha Barke <shraddha.6596@...il.com>,
        Dilek Uzulmez <dilekuzulmez@...il.com>,
        speakup@...ux-speakup.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org, vaishali.thakkar@...cle.com,
        ldv-project@...uxtesting.org
Subject: [PATCH] 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@...ras.ru>
---
 drivers/staging/speakup/kobjects.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/speakup/kobjects.c b/drivers/staging/speakup/kobjects.c
index 528cbdc..7fedee3 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;
 }
 
-- 
2.7.4