[PATCH] speakup: Add spinlock in synth_direct_store

[Samuel Thibault]

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)
---
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