[pvrusb2] [PATCH] pvrusb2: Fix oops on tear-down when radio support is not present

[Mike Isely]

The tabs are probably my fault.  I've been too used to just letting 
emacs deal automagically with indentation, and for projects I've done 
over the past ten years I typically configure emacs to just never use 
tabs at all.  However that driver source uses tabs - and I probably 
forgot to adjust emacs to deal with it.

Fortunately this isn't python, so tab vs spaces screwups won't break the 
correctness of the change.  But yeah, it may cause readability problems.  
I'll get that cleaned up.

  -Mike


On Sun, 27 Oct 2019, Diego Rivera wrote:

> The build is off to the races (24 thread concurrency), with the patch incorporated. It was offset by
> 10 lines, and had to ignore whitespace (for some reason the Ubuntu folks seem to have changed some
> indents to tabs...but only *some*....oh well).
> I'll let you know when it's ready and running.
> Cheers!
> On Sun, 2019-10-27 at 16:00 -0600, Diego Rivera wrote:
> > I'll do that today. I'm setting up a kernel build system now, should be able to fire off a build
> > soon.
> > Cheers!
> > -- 
> > 
> > 
> > 
> > Diego Rivera
> > 
> > On Sun, 2019-10-27 at 16:47 -0500, Mike Isely wrote:
> > > If I can get independent confirmation that this definitely helps matters, I will post the patch
> > > upstream.  Just being absolutely paranoid...
> > >   -Mike
> > > On Sun, 27 Oct 2019, Mike Isely wrote:
> > > > In some device configurations there's no radio or radio support in thedriver.  That's OK, as
> > > > the driver sets itself up accordingly.  Howeveron tear-down in these caes it's still trying to
> > > > tear down radiorelated context when there isn't anything there, leading todereferences through
> > > > a null pointer and chaos follows.
> > > > How this bug survived unfixed for 11 years in the pvrusb2 driver is a mystery to me.
> > > > Signed-off-by: Mike Isely <isely at pobox.com>--- drivers/media/usb/pvrusb2/pvrusb2-v4l2.c | 8
> > > > ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
> > > > diff --git a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c b/drivers/media/usb/pvrusb2/pvrusb2-
> > > > v4l2.cindex aa4fbc3e88cc..0a831849a2b0 100644--- a/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c+++ 
> > > > b/drivers/media/usb/pvrusb2/pvrusb2-v4l2.c@@ -909,8 +909,11 @@ static void
> > > > pvr2_v4l2_internal_check(struct pvr2_channel *chp) 	pvr2_v4l2_dev_disassociate_parent(vp
> > > > ->dev_video); 	pvr2_v4l2_dev_disassociate_parent(vp->dev_radio); 	if (!list_empty(&vp-
> > > > >dev_video->devbase.fh_list) ||-	    !list_empty(&vp->dev_radio->devbase.fh_list))+	    ((
> > > > vp->dev_radio != NULL) &&+	     !list_empty(&vp->dev_radio->devbase.fh_list))) {+	
> > > > 	pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_v4l2 internal_check exit-empty id=%p",vp); 		
> > > > return;+	} 	pvr2_v4l2_destroy_no_lock(vp); } @@ -946,7 +949,8 @@ static int
> > > > pvr2_v4l2_release(struct file *file) 	kfree(fhp); 	if (vp->channel.mc_head-
> > > > >disconnect_flag && 	    list_empty(&vp->dev_video->devbase.fh_list) &&-	    list_empty
> > > > (&vp->dev_radio->devbase.fh_list)) {+	    ((vp->dev_radio == NULL) ||+	     list_empt
> > > > y(&vp->dev_radio->devbase.fh_list))) { 		pvr2_v4l2_destroy_no_lock(vp); 	} 	
> > > > return 0;-- 2.20.1_______________________________________________pvrusb2 mailing 
> > > > listpvrusb2 at isely.net
> > > > http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2
> > > > 
> 

-- 

Mike Isely
isely @ isely (dot) net
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