Re: [PATCH v2 3/3] tpm: in tpm2_del_space check if ops pointer is still valid
From: Jarkko Sakkinen <jarkko@kernel.org>
Date: 2021-02-03 01:18:13
Also in:
lkml
On Tue, Feb 02, 2021 at 11:09:03PM +0100, Lino Sanfilippo wrote:
From: Lino Sanfilippo <redacted> In tpm2_del_space() the sessions are flushed by means of the tpm_chip operations. However the concerning operations pointer my already be NULL at
~~
may
What is "concerniog operations"? Unfamiliar term. Maybe just consistently
se chip->ops? Now you have also "tpm_chip operations" and chip->ops, in
addition to "concerning operations" in one paragraph commit message.
this time in case that the chip has been unregistered (see tpm_chip_unregister() which calls tpm_del_char_device() which sets chip->ops to NULL). Before accessing chip->ops check if it is still valid. Skip flushing the sessions in this case. Signed-off-by: Lino Sanfilippo <redacted>
Instead of cross referencing please describe the scenario (i.e. the sequence of operations) of failure. Fixes tag is also missing.
quoted hunk ↗ jump to hunk
--- drivers/char/tpm/tpm2-space.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c index 784b8b3..9a29a40 100644 --- a/drivers/char/tpm/tpm2-space.c +++ b/drivers/char/tpm/tpm2-space.c@@ -58,12 +58,17 @@ int tpm2_init_space(struct tpm_space *space, unsigned int buf_size) void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space) { - mutex_lock(&chip->tpm_mutex); - if (!tpm_chip_start(chip)) { - tpm2_flush_sessions(chip, space); - tpm_chip_stop(chip); + down_read(&chip->ops_sem); + if (chip->ops) { + mutex_lock(&chip->tpm_mutex); + if (!tpm_chip_start(chip)) { + tpm2_flush_sessions(chip, space); + tpm_chip_stop(chip); + } + mutex_unlock(&chip->tpm_mutex); } - mutex_unlock(&chip->tpm_mutex); + up_read(&chip->ops_sem); + kfree(space->context_buf); kfree(space->session_buf); }-- 2.7.4
/Jarkko