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-rw-r--r--drivers/char/mem.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index a33163dbb913..5bb1985ec484 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -381,6 +381,9 @@ static ssize_t read_kmem(struct file *file, char __user *buf,
char *kbuf; /* k-addr because vread() takes vmlist_lock rwlock */
int err = 0;
+ if (!pfn_valid(PFN_DOWN(p)))
+ return -EIO;
+
read = 0;
if (p < (unsigned long) high_memory) {
low_count = count;
@@ -509,6 +512,9 @@ static ssize_t write_kmem(struct file *file, const char __user *buf,
char *kbuf; /* k-addr because vwrite() takes vmlist_lock rwlock */
int err = 0;
+ if (!pfn_valid(PFN_DOWN(p)))
+ return -EIO;
+
if (p < (unsigned long) high_memory) {
unsigned long to_write = min_t(unsigned long, count,
(unsigned long)high_memory - p);