From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Jarkko Sakkinen
<jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
Cc: "moderated list:TPM DEVICE DRIVER"
<tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] tpm: fix crash in tpm_tis deinitialization
Date: Wed, 13 Apr 2016 11:04:26 -0600 [thread overview]
Message-ID: <20160413170426.GA28411@obsidianresearch.com> (raw)
In-Reply-To: <20160413065805.GB6986-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
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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WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Peter Huewe <peterhuewe@gmx.de>,
Marcel Selhorst <tpmdd@selhorst.net>,
"moderated list:TPM DEVICE DRIVER"
<tpmdd-devel@lists.sourceforge.net>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tpm: fix crash in tpm_tis deinitialization
Date: Wed, 13 Apr 2016 11:04:26 -0600 [thread overview]
Message-ID: <20160413170426.GA28411@obsidianresearch.com> (raw)
In-Reply-To: <20160413065805.GB6986@intel.com>
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
next prev parent reply other threads:[~2016-04-13 17:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-11 16:05 [PATCH] tpm: fix crash in tpm_tis deinitialization Jarkko Sakkinen
2016-04-11 16:05 ` Jarkko Sakkinen
[not found] ` <1460390720-9509-1-git-send-email-jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2016-04-11 17:40 ` Jason Gunthorpe
2016-04-11 17:40 ` Jason Gunthorpe
[not found] ` <20160411174037.GA371-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2016-04-12 4:26 ` Jarkko Sakkinen
2016-04-12 4:26 ` Jarkko Sakkinen
[not found] ` <20160412042627.GA6608-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-04-12 17:26 ` Jason Gunthorpe
2016-04-12 17:26 ` Jason Gunthorpe
[not found] ` <20160412172655.GA5759-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2016-04-13 6:16 ` Jarkko Sakkinen
2016-04-13 6:16 ` Jarkko Sakkinen
2016-04-13 6:58 ` Jarkko Sakkinen
[not found] ` <20160413065805.GB6986-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-04-13 17:04 ` Jason Gunthorpe [this message]
2016-04-13 17:04 ` Jason Gunthorpe
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