From 5e85bd057f0cb29881e3d55d29f48bb55bd2f450 Mon Sep 17 00:00:00 2001 From: Trent Piepho Date: Thu, 30 Mar 2006 15:53:32 -0300 Subject: [PATCH] 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 Signed-off-by: Andrew de Quincey Signed-off-by: Mauro Carvalho Chehab --- drivers/media/dvb/dvb-core/dmxdev.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/media/dvb/dvb-core/dmxdev.c b/drivers/media/dvb/dvb-core/dmxdev.c index 09e96e9ddbd..04578df3f24 100644 --- a/drivers/media/dvb/dvb-core/dmxdev.c +++ b/drivers/media/dvb/dvb-core/dmxdev.c @@ -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 }; -- 2.41.0