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Subject: Re: [PATCH v3 1/2] tpm: fix reference counting for struct tpm_chip
From:   James Bottomley <James.Bottomley@HansenPartnership.com>
To:     Stefan Berger <stefanb@linux.ibm.com>,
        Lino Sanfilippo <LinoSanfilippo@gmx.de>, peterhuewe@gmx.de,
        jarkko@kernel.org
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        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lino Sanfilippo <l.sanfilippo@kunbus.com>
Date:   Thu, 04 Feb 2021 18:01:30 -0800
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On Thu, 2021-02-04 at 20:44 -0500, Stefan Berger wrote:
> To clarify: When I tested this I had *both* patches applied. Without
> the patches I got the null pointer exception in tpm2_del_space(). The
> 2nd patch alone solves that issue when using the steps above.


Yes, I can't confirm the bug either.  I only have lpc tis devices, so
it could be something to do with spi, but when I do

python3 in one shell

>>> fd = open("/dev/tpmrm0", "wb")

do rmmod tpm_tis in another shell

>>> buf = bytearray(20)
>>> fd.write(buf)
20

so I don't see the oops you see on write.  However

>>> fd.close()

And it oopses here in tpm2_del_space

James