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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: Tyrel Datwyler <tyreld@linux.ibm.com>,
	jarkko@kernel.org, peterhuewe@gmx.de,
	linux-integrity@vger.kernel.org, Korrapati.Likhitha@ibm.com,
	pavrampu@in.ibm.com, linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org, gcwilson@us.ibm.com,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] tpm: Fix kexec crash due to access to ops NULL pointer (powerpc)
Date: Mon, 20 Dec 2021 21:13:20 -0400	[thread overview]
Message-ID: <20211221011320.GM6467@ziepe.ca> (raw)
In-Reply-To: <d9eafa8f-4006-4bc2-c09b-6b02a14c6ef3@linux.ibm.com>

On Mon, Dec 20, 2021 at 08:05:58PM -0500, Stefan Berger wrote:

> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb7e109..4cb908349b31 100644
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -473,15 +473,8 @@ static void tpm_del_char_device(struct tpm_chip *chip)
>         mutex_unlock(&idr_lock);
> 
>         /* Make the driver uncallable. */
> -       down_write(&chip->ops_sem);
> -       if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> -               if (!tpm_chip_start(chip)) {
> -                       tpm2_shutdown(chip, TPM2_SU_CLEAR);
> -                       tpm_chip_stop(chip);
> -               }
> -       }
> -       chip->ops = NULL;
> -       up_write(&chip->ops_sem);
> +       if (chip->ops)

ops cannot be read without locking

Jason

WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: Korrapati.Likhitha@ibm.com, Tyrel Datwyler <tyreld@linux.ibm.com>,
	pavrampu@in.ibm.com, linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org, jarkko@kernel.org,
	gcwilson@us.ibm.com, peterhuewe@gmx.de,
	linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org
Subject: Re: [PATCH] tpm: Fix kexec crash due to access to ops NULL pointer (powerpc)
Date: Mon, 20 Dec 2021 21:13:20 -0400	[thread overview]
Message-ID: <20211221011320.GM6467@ziepe.ca> (raw)
In-Reply-To: <d9eafa8f-4006-4bc2-c09b-6b02a14c6ef3@linux.ibm.com>

On Mon, Dec 20, 2021 at 08:05:58PM -0500, Stefan Berger wrote:

> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb7e109..4cb908349b31 100644
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -473,15 +473,8 @@ static void tpm_del_char_device(struct tpm_chip *chip)
>         mutex_unlock(&idr_lock);
> 
>         /* Make the driver uncallable. */
> -       down_write(&chip->ops_sem);
> -       if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> -               if (!tpm_chip_start(chip)) {
> -                       tpm2_shutdown(chip, TPM2_SU_CLEAR);
> -                       tpm_chip_stop(chip);
> -               }
> -       }
> -       chip->ops = NULL;
> -       up_write(&chip->ops_sem);
> +       if (chip->ops)

ops cannot be read without locking

Jason

  reply	other threads:[~2021-12-21  1:13 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-12-12  1:28 [PATCH] tpm: Fix kexec crash due to access to ops NULL pointer (powerpc) Stefan Berger
2021-12-12  1:28 ` Stefan Berger
2021-12-20  5:17 ` Sachin Sant
2021-12-20  5:17   ` Sachin Sant
2021-12-21  0:39 ` Tyrel Datwyler
2021-12-21  1:05   ` Stefan Berger
2021-12-21  1:13     ` Jason Gunthorpe [this message]
2021-12-21  1:13       ` Jason Gunthorpe
2021-12-21  1:31       ` Stefan Berger
2021-12-21  1:31         ` Stefan Berger
2021-12-21  1:37         ` Tyrel Datwyler
2021-12-21  1:37           ` Tyrel Datwyler
2021-12-21  1:34     ` Tyrel Datwyler
2021-12-21  8:47 ` Jarkko Sakkinen
2021-12-21  8:47   ` Jarkko Sakkinen
2021-12-21 14:01   ` Stefan Berger
2021-12-21 14:01     ` Stefan Berger
2021-12-21 14:17     ` Stefan Berger
2021-12-21 14:17       ` Stefan Berger
2021-12-29  0:10     ` Jarkko Sakkinen
2021-12-29  0:10       ` Jarkko Sakkinen

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