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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 22:28:06 +0300	[thread overview]
Message-ID: <20200205192806.GE24804@kadam> (raw)
In-Reply-To: <CAPcyv4jkTHeS2zTmYRoFi+evMemhmMkvPVcsBOQGXinGq6JyiQ@mail.gmail.com>

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.

   511  }

The fix is probably to make nd_device_register() return an error code so
we can do:

	ret = nd_device_register(dev);
	if (ret) {
		device_put(&nvdimm->dev);
		return NULL;
	}

	return nvdimm;

regards,
dan carpenter
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  reply	other threads:[~2020-02-05 19:28 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 [this message]
2020-02-05 20:04             ` Dan Williams
2020-02-05 20:18               ` Dan Carpenter

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