Re: [PATCH] tpm: fix crash in tpm_tis deinitialization

From	Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] tpm: fix crash in tpm_tis deinitialization
Date	2016-04-13 19:10 +0200
Message-ID	<rnwsG-4zJ-9@gated-at.bofh.it> (permalink)
References	(1 earlier) <rmO8h-1am-7@gated-at.bofh.it> <rmY7E-ZZ-1@gated-at.bofh.it> <rnaiu-2Gv-15@gated-at.bofh.it> <rnmjE-4Uv-19@gated-at.bofh.it> <rnmWl-5i7-9@gated-at.bofh.it>
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On Wed, Apr 13, 2016 at 09:58:05AM +0300, Jarkko Sakkinen wrote:
> > > It prevents everything including the kernel from issuing a command
> >                          ^^^^^^^^^^^^^^^^^^^^
> > 
> > That lock is not used to exclude kernel access. Read lock is only taken
> > for the user space device in tpm-dev.c.
> 
> My bad. For the in-kernel API it is taken through tpm_find_get().

Right. At this point any thing that can run in-kernel concurrently
with the write exclusion is a kernel bug. Those places will need to
grab the read side of the lock.

Jason

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[PATCH] tpm: fix crash in tpm_tis deinitialization Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2016-04-11 18:10 +0200
  Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2016-04-11 19:50 +0200
    Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2016-04-12 06:30 +0200
      Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2016-04-12 19:30 +0200
        Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2016-04-13 08:20 +0200
          Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2016-04-13 09:00 +0200
            Re: [PATCH] tpm: fix crash in tpm_tis deinitialization Jason Gunthorpe <jgunthorpe@obsidianresearch.com> - 2016-04-13 19:10 +0200

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