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V4L/DVB: DVB: fix dvr node refcounting 

In dvb_dvr_release, there is a test dvbdev->users==-1, but users are
never negative. This error results in hung tasks:
  task                        PC stack   pid father
bash          D ffffffffa000c948     0  3264   3170 0x00000000
 ffff88003aec5ce8 0000000000000086 0000000000011f80 0000000000011f80
 ffff88003aec5fd8 ffff88003aec5fd8 ffff88003b848670 0000000000011f80
 ffff88003aec5fd8 0000000000011f80 ffff88003e02a030 ffff88003b848670
Call Trace:
 [<ffffffff813dd4a5>] dvb_dmxdev_release+0xc5/0x130
 [<ffffffff8107b750>] ? autoremove_wake_function+0x0/0x40
 [<ffffffffa00013a2>] dvb_usb_adapter_dvb_exit+0x42/0x70 [dvb_usb]
 [<ffffffffa0000525>] dvb_usb_exit+0x55/0xd0 [dvb_usb]
 [<ffffffffa00005ee>] dvb_usb_device_exit+0x4e/0x70 [dvb_usb]
 [<ffffffffa000a065>] af9015_usb_device_exit+0x55/0x60 [dvb_usb_af9015]
 [<ffffffff813a3f05>] usb_unbind_interface+0x55/0x1a0
 [<ffffffff81316000>] __device_release_driver+0x70/0xe0
...

So check against 1 there instead.

BTW why's the TODO there? Adding TODOs to the code without
descriptions is like adding nothing.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Jiri Slaby 2010-07-18 15:34:18 -03:00 committed by Mauro Carvalho Chehab
parent bbafc0cb6c
commit 1c488ea9d5
1 changed files with 1 additions and 1 deletions
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2
drivers/media/dvb/dvb-core/dmxdev.c
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@ -207,7 +207,7 @@ static int dvb_dvr_release(struct inode *inode, struct file *file)
}
/* TODO */
dvbdev->users--;
if(dvbdev->users==-1 && dmxdev->exit==1) {
if (dvbdev->users == 1 && dmxdev->exit == 1) {
fops_put(file->f_op);
file->f_op = NULL;
mutex_unlock(&dmxdev->mutex);