linux-kernel - Re: [PATCH =v2 1/3] tpm: fix invalid locking in NONBLOCKING mode

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Message-ID: <a7595cde0003f5799977353d2436e621928d0723.camel@linux.intel.com>
Date:   Tue, 17 Dec 2019 03:32:33 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Tadeusz Struk <tadeusz.struk@...el.com>
Cc:     peterz@...radead.org, linux-kernel@...r.kernel.org, jgg@...pe.ca,
        mingo@...hat.com, jeffrin@...agiritech.edu.in,
        linux-integrity@...r.kernel.org, will@...nel.org, peterhuewe@....de
Subject: Re: [PATCH =v2 1/3] tpm: fix invalid locking in NONBLOCKING mode

On Thu, 2019-12-12 at 09:48 -0800, Tadeusz Struk wrote:
> When an application sends TPM commands in NONBLOCKING mode
> the driver holds chip->tpm_mutex returning from write(),
> which triggers: "WARNING: lock held when returning to user space".
> To fix this issue the driver needs to release the mutex before
> returning and acquire it again in tpm_dev_async_work() before
> sending the command.

This is way better, thank you. I'll put this to my rc3 PR.

> 
> Cc: stable@...r.kernel.org
> Fixes: 9e1b74a63f776 (tpm: add support for nonblocking operation)
> Reported-by: Jeffrin Jose T <jeffrin@...agiritech.edu.in>
> Tested-by: Jeffrin Jose T <jeffrin@...agiritech.edu.in>
> Signed-off-by: Tadeusz Struk <tadeusz.struk@...el.com>

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>

/Jarkko