From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Berger Subject: Re: [PATCH] tpm: vtpm_proxy: Do not access host's event log Date: Sun, 20 Nov 2016 09:46:12 -0500 Message-ID: <1f165294-07bc-6c06-3a3b-be596fc12d58@linux.vnet.ibm.com> References: <1479306245-14456-1-git-send-email-stefanb@linux.vnet.ibm.com> <20161116153731.pmmnxiai7ouuj6qf@intel.com> <3a38ddc6-1758-ae82-3df3-9cc55906880d@linux.vnet.ibm.com> <65f392b6-5141-c726-dacb-a1649ea215de@linux.vnet.ibm.com> <20161116200759.GA19593@obsidianresearch.com> <20161117181006.GA26039@obsidianresearch.com> <20161117183328.GC26039@obsidianresearch.com> <513da75c-6221-39ce-2718-19290c216ff1@linux.vnet.ibm.com> <20161119183255.GB22775@obsidianresearch.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161119183255.GB22775-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jason Gunthorpe Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On 11/19/2016 01:32 PM, Jason Gunthorpe wrote: > On Thu, Nov 17, 2016 at 06:15:20PM -0500, Stefan Berger wrote: > >>>> Further, I had the impression that the error unwinding following -ENODEV has >>>> an issue related to sysfs. >>> I don't follow this comment.. >> I have encountered this error here, which gets masked when applying the >> previously shown patch. > If tpm_chip_register fails vtpm must not call tpm_chip_unregister: > >> [ 58.271017] [] dpm_sysfs_remove+0x22/0x60 >> [ 58.271017] [] device_del+0x58/0x280 >> [ 58.271017] [] tpm_chip_unregister+0x40/0xb0 [tpm] >> [ 58.271017] [] vtpm_proxy_fops_release+0x40/0x60 [tpm_vtpm_proxy] > So, this is a vtpm thing I missed for 'tpm: Get rid of TPM_CHIP_FLAG_REGISTERED' > > Does this do the trick? Yes, it does the trick. I tested this now with your other fix-patch applied to Jarkko's tree. I injected a fault by returning -EIO from tpm_read_log_acpi(), which otherwise would cause the crash. Tested-by: Stefan Berger > > diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c > index 3d6f6ca81def75..d3a41f9d65c85c 100644 > --- a/drivers/char/tpm/tpm_vtpm_proxy.c > +++ b/drivers/char/tpm/tpm_vtpm_proxy.c > @@ -42,6 +42,7 @@ struct proxy_dev { > long state; /* internal state */ > #define STATE_OPENED_FLAG BIT(0) > #define STATE_WAIT_RESPONSE_FLAG BIT(1) /* waiting for emulator response */ > +#define STATE_REGISTERED_FLAG BIT(2) > > size_t req_len; /* length of queued TPM request */ > size_t resp_len; /* length of queued TPM response */ > @@ -372,6 +373,7 @@ static void vtpm_proxy_work(struct work_struct *work) > if (rc) > goto err; > > + proxy_dev->state |= STATE_REGISTERED_FLAG; > return; > > err: > @@ -516,7 +518,8 @@ static void vtpm_proxy_delete_device(struct proxy_dev *proxy_dev) > */ > vtpm_proxy_fops_undo_open(proxy_dev); > > - tpm_chip_unregister(proxy_dev->chip); > + if (proxy_dev->state & STATE_REGISTERED_FLAG) > + tpm_chip_unregister(proxy_dev->chip); > > vtpm_proxy_delete_proxy_dev(proxy_dev); > } > ------------------------------------------------------------------------------