linux-kernel - Re: [PATCH 1/2] tpm: Fix error handling in async work

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Message-ID: <3c835b05-b476-4ea9-929f-0131fa7a3446@gmail.com>
Date:   Tue, 28 Dec 2021 16:08:42 -0800
From:   Tadeusz Struk <tstruk@...il.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     Jason Gunthorpe <jgg@...pe.ca>, linux-integrity@...r.kernel.org,
        stable@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] tpm: Fix error handling in async work

On 12/28/21 15:47, Jarkko Sakkinen wrote:
>> When an invalid (non existing) handle is used in a tpm command,
>> that uses the resource manager interface (/dev/tpmrm0) the resource
>> manager tries to load it from its internal cache, but fails and
>> returns an -EINVAL error to the caller. The existing async handler
>> doesn't handle these error cases currently and the condition in the
>> poll handler never returns mask with EPOLLIN set causing the userspace
>> code to get stack. Make sure that error conditions also contribute
>> to the poll mask so that a correct error code could passed back
>> to the caller.
> Can you instead describe a failure scenario? This is very cryptic.

The problem is that the poll call blocks and the application gets stuck
until the tpm_timeout_work() wakes it up after 120 sec (jiffies + (120 * HZ)).
I will update the description, fix all the typos, and resend it.

Thanks,
Tadeusz