From: Dan Carpenter <dan.carpenter@oracle.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [bug report] libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure
Date: Wed, 5 Feb 2020 23:18:34 +0300 [thread overview]
Message-ID: <20200205201834.GF24804@kadam> (raw)
In-Reply-To: <CAPcyv4gySPR0+sC1-xQsXirprX96Kyk764kUOuada+6djTXUjQ@mail.gmail.com>
On Wed, Feb 05, 2020 at 12:04:15PM -0800, Dan Williams wrote:
> On Wed, Feb 5, 2020 at 11:28 AM Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >
> > On Wed, Feb 05, 2020 at 11:16:22AM -0800, Dan Williams wrote:
> > > Ugh, sorry I thought you were pointing out that there's too many
> > > put_device() not the use after free. Yes, the use after free is a bug
> > > that needs fixing.
> >
> > I am complaining about the device_puts... If we call device_put()
> > twice then it cause a problem in __nvdimm_create()
> >
> > drivers/nvdimm/dimm_devs.c
> > 506 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
> > 507 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
> > 508 nd_device_register(dev);
> > 509
> > 510 return nvdimm;
> > ^^^^^^
> > If we call device_put() twice then we this pointer within 4 seconds.
>
> "we this pointer"? We "what" this pointer. 4 seconds is relative to a
> runtime test case?
>
Sorry. I meant we *free* it. The second device_put() leads to a
nvdimm_release(dev) where dev is "&nvdimm->dev" within 0-4 seconds.
Most times it will free it immediately but if you have
CONFIG_DEBUG_KOBJECT_RELEASE enabled then it will wait between 1-4
seconds and then free nvdimm. It's a config option, not a runtime
thing.
regards,
dan carpenter
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prev parent reply other threads:[~2020-02-05 20:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 12:38 [bug report] libnvdimm, nvdimm: dimm driver and base libnvdimm device-driver infrastructure Dan Carpenter
2020-02-05 17:47 ` Dan Williams
2020-02-05 18:10 ` Dan Carpenter
2020-02-05 18:23 ` Dan Williams
2020-02-05 19:08 ` Dan Carpenter
2020-02-05 19:16 ` Dan Williams
2020-02-05 19:28 ` Dan Carpenter
2020-02-05 20:04 ` Dan Williams
2020-02-05 20:18 ` Dan Carpenter [this message]
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