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Commit 5e85bd05 authored by Trent Piepho's avatar Trent Piepho Committed by Mauro Carvalho Chehab
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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: default avatarTrent Piepho <xyzzy@speakeasy.org>
Signed-off-by: default avatarAndrew de Quincey <adq_dvb@lidskialf.net>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@infradead.org>
parent 2f03ee8e

drivers/media/dvb/dvb-core/dmxdev.c

+9 −3
Original line number Diff line number Diff line
@@ -141,12 +141,18 @@ static int dvb_dvr_open(struct inode *inode, struct file *file) 
	}



	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 @@ static int dvb_dvr_release(struct inode *inode, struct file *file) 
						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 file_operations dvb_dvr_fops = { 


static struct dvb_device dvbdev_dvr = {

	.priv = NULL,

	.users = 1,

	.writers = 1,

	.readers = 1,

	.fops = &dvb_dvr_fops

};