From: Stefan Berger <stefanb@linux.ibm.com> To: Jason Gunthorpe <jgg@ziepe.ca> 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 20:31:27 -0500 [thread overview] Message-ID: <f80e33d2-948d-f885-b063-245eb37de8c1@linux.ibm.com> (raw) In-Reply-To: <20211221011320.GM6467@ziepe.ca> On 12/20/21 20:13, Jason Gunthorpe wrote: > 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 This here could be an alternative: diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7772b475ebc0 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,7 +474,7 @@ static void tpm_del_char_device(struct tpm_chip *chip) /* Make the driver uncallable. */ down_write(&chip->ops_sem); - if (chip->flags & TPM_CHIP_FLAG_TPM2) { + if (chip->ops && chip->flags & TPM_CHIP_FLAG_TPM2) { if (!tpm_chip_start(chip)) { tpm2_shutdown(chip, TPM2_SU_CLEAR); tpm_chip_stop(chip); Stefan > > Jason
WARNING: multiple messages have this Message-ID (diff)
From: Stefan Berger <stefanb@linux.ibm.com> To: Jason Gunthorpe <jgg@ziepe.ca> 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 20:31:27 -0500 [thread overview] Message-ID: <f80e33d2-948d-f885-b063-245eb37de8c1@linux.ibm.com> (raw) In-Reply-To: <20211221011320.GM6467@ziepe.ca> On 12/20/21 20:13, Jason Gunthorpe wrote: > 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 This here could be an alternative: diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..7772b475ebc0 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -474,7 +474,7 @@ static void tpm_del_char_device(struct tpm_chip *chip) /* Make the driver uncallable. */ down_write(&chip->ops_sem); - if (chip->flags & TPM_CHIP_FLAG_TPM2) { + if (chip->ops && chip->flags & TPM_CHIP_FLAG_TPM2) { if (!tpm_chip_start(chip)) { tpm2_shutdown(chip, TPM2_SU_CLEAR); tpm_chip_stop(chip); Stefan > > Jason
next prev parent reply other threads:[~2021-12-21 1:31 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 2021-12-21 1:13 ` Jason Gunthorpe 2021-12-21 1:31 ` Stefan Berger [this message] 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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