V4L/DVB (3672): Fix memory leak in dvr open
The dvr device could be opened multiple times simultaneously in O_RDONLY mode.
Each open after the first would allocate a new dvr buffer (1880 KB) and leak
the old buffer. The first close would de-allocate the dvr buffer and cause
all other open dvrs to stop working. This patch allows only a single O_RDONLY
open of the drv device, as per the API specification. Multiple O_WRONLY opens
are still allowed and don't appear to cause any problems.
Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Andrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c
index 09e96e9..04578df 100644
--- a/drivers/media/dvb/dvb-core/dmxdev.c
+++ b/drivers/media/dvb/dvb-core/dmxdev.c
@@ -141,12 +141,18 @@
}
if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
- void *mem = vmalloc(DVR_BUFFER_SIZE);
+ void *mem;
+ if (!dvbdev->readers) {
+ mutex_unlock(&dmxdev->mutex);
+ return -EBUSY;
+ }
+ mem = vmalloc(DVR_BUFFER_SIZE);
if (!mem) {
mutex_unlock(&dmxdev->mutex);
return -ENOMEM;
}
dvb_ringbuffer_init(&dmxdev->dvr_buffer, mem, DVR_BUFFER_SIZE);
+ dvbdev->readers--;
}
if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
@@ -184,6 +190,7 @@
dmxdev->dvr_orig_fe);
}
if ((file->f_flags & O_ACCMODE) == O_RDONLY) {
+ dvbdev->readers++;
if (dmxdev->dvr_buffer.data) {
void *mem = dmxdev->dvr_buffer.data;
mb();
@@ -1029,8 +1036,7 @@
static struct dvb_device dvbdev_dvr = {
.priv = NULL,
- .users = 1,
- .writers = 1,
+ .readers = 1,
.fops = &dvb_dvr_fops
};