Re: [PATCH] tpm: Fix kexec crash due to access to ops NULL pointer (powerpc)
From: Jason Gunthorpe <jgg@ziepe.ca>
Date: 2021-12-21 01:13:25
Also in:
linux-integrity, linuxppc-dev, lkml
On Mon, Dec 20, 2021 at 08:05:58PM -0500, Stefan Berger wrote:
quoted hunk ↗ jump to hunk
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