From: Dan Carpenter <dan.carpenter@oracle.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
royale@zerezo.com, USB <linux-usb@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
syzbot+b4d54814b339b5c6bbd4@syzkaller.appspotmail.com
Subject: Re: [RFT][PATCH v1] media: zr364xx: Fix memory leak in ->probe()
Date: Tue, 5 Jan 2021 19:04:48 +0300 [thread overview]
Message-ID: <20210105160448.GY2831@kadam> (raw)
In-Reply-To: <20210105143741.GK4077@smile.fi.intel.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
prev parent reply other threads:[~2021-01-05 16:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 21:19 [RFT][PATCH v1] media: zr364xx: Fix memory leak in ->probe() Andy Shevchenko
2020-12-31 1:53 ` Ezequiel Garcia
2020-12-31 1:53 ` syzbot
2021-01-05 14:00 ` Dan Carpenter
2021-01-05 14:37 ` Andy Shevchenko
2021-01-05 16:04 ` Dan Carpenter [this message]
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