Re: [RFT][PATCH v1] media: zr364xx: Fix memory leak in ->probe()

[Dan Carpenter <dan.carpenter@oracle.com>]

On Tue, Jan 05, 2021 at 04:37:41PM +0200, Andy Shevchenko wrote:
> On Tue, Jan 05, 2021 at 05:00:45PM +0300, Dan Carpenter wrote:
> > On Wed, Dec 30, 2020 at 11:19:18PM +0200, Andy Shevchenko wrote:
> > > When ->probe() fails in some cases it may not free resources.
> > > Replace few separated calls by v4l2_device_put() to clean up
> > > everything.
> > > 
> > 
> > The clean up everything style of error handling is always buggy.
> > 
> > For example, in this case, all the early error paths will now crash
> > instead of leaking.  The __videobuf_free() function will Oops when it
> > dereferences "q->int_ops->magic".
> > 
> > 	MAGIC_CHECK(q->int_ops->magic, MAGIC_QTYPE_OPS);
> > 
> > The "q->int_ops" pointer is set in videobuf_queue_vmalloc_init().  There
> > are probably other bugs as well.  It's almost impossible to audit this
> > style of error handling either for completeness or for crashyness.
> 
> Feel free to submit better fix, thanks!

Sure.  I'm too tired to think straight today.

I see now that syzbot actually discovered the Oops in __videobuf_free()
as well...  I'm sort of surprised that the original code never called
zr364xx_release().  We might have another reference leak somewhere...

regards,
dan carpenter