Avoid race condition at shutdown by shutting downn the TPM 2.0
devices synchronously. This eliminates the condition when the
shutdown sequence sets chip->ops to NULL leading to the following:
[ 1586.593561][ T8669] tpm2_del_space+0x28/0x73
[ 1586.598718][ T8669] tpmrm_release+0x27/0x33wq
[ 1586.603774][ T8669] __fput+0x109/0x1d
[ 1586.608380][ T8669] task_work_run+0x7c/0x90
[ 1586.613414][ T8669] prepare_exit_to_usermode+0xb8/0x128
[ 1586.619522][ T8669] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1586.626068][ T8669] RIP: 0033:0x4cb4bb
Signed-off-by: Sergey Temerkhanov <[email protected]>
---
drivers/char/tpm/tpm-chip.c | 2 ++
drivers/char/tpm/tpm-dev.c | 20 +++++++++++++-------
drivers/char/tpm/tpmrm-dev.c | 3 +++
include/linux/tpm.h | 6 ++++--
4 files changed, 22 insertions(+), 9 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index ddaeceb7e109..e94148b8e180 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -295,6 +295,7 @@ static int tpm_class_shutdown(struct device *dev)
{
struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
+ wait_event_idle(chip->waitq, !atomic_read(&chip->refcount));
down_write(&chip->ops_sem);
if (chip->flags & TPM_CHIP_FLAG_TPM2) {
if (!tpm_chip_start(chip)) {
@@ -330,6 +331,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
mutex_init(&chip->tpm_mutex);
init_rwsem(&chip->ops_sem);
+ init_waitqueue_head(&chip->waitq);
chip->ops = ops;
diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
index e2c0baa69fef..8558f0f7382c 100644
--- a/drivers/char/tpm/tpm-dev.c
+++ b/drivers/char/tpm/tpm-dev.c
@@ -19,27 +19,32 @@ static int tpm_open(struct inode *inode, struct file *file)
{
struct tpm_chip *chip;
struct file_priv *priv;
+ int ret = 0;
chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
/* It's assured that the chip will be opened just once,
- * by the check of is_open variable, which is protected
- * by driver_lock. */
- if (test_and_set_bit(0, &chip->is_open)) {
+ * by the check of the chip reference count.
+ */
+ if (atomic_fetch_inc(&chip->refcount)) {
dev_dbg(&chip->dev, "Another process owns this TPM\n");
- return -EBUSY;
+ ret = -EBUSY;
+ goto out;
}
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (priv == NULL)
+ if (priv == NULL) {
+ ret = -ENOMEM;
goto out;
+ }
tpm_common_open(file, chip, priv, NULL);
return 0;
out:
- clear_bit(0, &chip->is_open);
+ atomic_dec(&chip->refcount);
+ wake_up_all(&chip->waitq);
return -ENOMEM;
}
@@ -51,7 +56,8 @@ static int tpm_release(struct inode *inode, struct file *file)
struct file_priv *priv = file->private_data;
tpm_common_release(file, priv);
- clear_bit(0, &priv->chip->is_open);
+ atomic_dec(&priv->chip->refcount);
+ wake_up_all(&priv->chip->waitq);
kfree(priv);
return 0;
diff --git a/drivers/char/tpm/tpmrm-dev.c b/drivers/char/tpm/tpmrm-dev.c
index eef0fb06ea83..fb3cb7b03814 100644
--- a/drivers/char/tpm/tpmrm-dev.c
+++ b/drivers/char/tpm/tpmrm-dev.c
@@ -28,6 +28,7 @@ static int tpmrm_open(struct inode *inode, struct file *file)
}
tpm_common_open(file, chip, &priv->priv, &priv->space);
+ atomic_inc(&chip->refcount);
return 0;
}
@@ -39,6 +40,8 @@ static int tpmrm_release(struct inode *inode, struct file *file)
tpm_common_release(file, fpriv);
tpm2_del_space(fpriv->chip, &priv->space);
+ atomic_dec(&fpriv->chip->refcount);
+ wake_up_all(&fpriv->chip->waitq);
kfree(priv);
return 0;
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 8f4ff39f51e7..0c8842783823 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -22,6 +22,7 @@
#include <linux/cdev.h>
#include <linux/fs.h>
#include <linux/highmem.h>
+#include <linux/atomic.h>
#include <crypto/hash_info.h>
#define TPM_DIGEST_SIZE 20 /* Max TPM v1.2 PCR size */
@@ -128,8 +129,9 @@ struct tpm_chip {
unsigned int flags;
- int dev_num; /* /dev/tpm# */
- unsigned long is_open; /* only one allowed */
+ int dev_num; /* /dev/tpm# */
+ atomic_t refcount; /* /dev/tmp# can only be opened once */
+ wait_queue_head_t waitq; /* Wait queue for synchronous ops */
char hwrng_name[64];
struct hwrng hwrng;
--
2.25.1
Hi Sergey,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on char-misc/char-misc-testing]
[also build test WARNING on linux/master linus/master v5.10 next-20201215]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Sergey-Temerkhanov/tpm-Rework-open-close-shutdown-to-avoid-races/20201215-214304
base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git 93f998879cd95b3e4f2836e7b17d6d5ae035cf90
config: m68k-randconfig-r012-20201215 (attached as .config)
compiler: m68k-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/b1f6f05f320b6b609ff70567a701e12504783b02
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Sergey-Temerkhanov/tpm-Rework-open-close-shutdown-to-avoid-races/20201215-214304
git checkout b1f6f05f320b6b609ff70567a701e12504783b02
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
drivers/char/tpm/tpm-dev.c: In function 'tpm_open':
>> drivers/char/tpm/tpm-dev.c:22:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
22 | int ret = 0;
| ^~~
vim +/ret +22 drivers/char/tpm/tpm-dev.c
17
18 static int tpm_open(struct inode *inode, struct file *file)
19 {
20 struct tpm_chip *chip;
21 struct file_priv *priv;
> 22 int ret = 0;
23
24 chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
25
26 /* It's assured that the chip will be opened just once,
27 * by the check of the chip reference count.
28 */
29 if (atomic_fetch_inc(&chip->refcount)) {
30 dev_dbg(&chip->dev, "Another process owns this TPM\n");
31 ret = -EBUSY;
32 goto out;
33 }
34
35 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
36 if (priv == NULL) {
37 ret = -ENOMEM;
38 goto out;
39 }
40
41 tpm_common_open(file, chip, priv, NULL);
42
43 return 0;
44
45 out:
46 atomic_dec(&chip->refcount);
47 wake_up_all(&chip->waitq);
48 return -ENOMEM;
49 }
50
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]
On Tue, Dec 15, 2020 at 04:38:01PM +0300, Sergey Temerkhanov wrote:
> Avoid race condition at shutdown by shutting downn the TPM 2.0
> devices synchronously. This eliminates the condition when the
> shutdown sequence sets chip->ops to NULL leading to the following:
>
> [ 1586.593561][ T8669] tpm2_del_space+0x28/0x73
> [ 1586.598718][ T8669] tpmrm_release+0x27/0x33wq
> [ 1586.603774][ T8669] __fput+0x109/0x1d
> [ 1586.608380][ T8669] task_work_run+0x7c/0x90
> [ 1586.613414][ T8669] prepare_exit_to_usermode+0xb8/0x128
> [ 1586.619522][ T8669] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 1586.626068][ T8669] RIP: 0033:0x4cb4bb
>
> Signed-off-by: Sergey Temerkhanov <[email protected]>
> drivers/char/tpm/tpm-chip.c | 2 ++
> drivers/char/tpm/tpm-dev.c | 20 +++++++++++++-------
> drivers/char/tpm/tpmrm-dev.c | 3 +++
> include/linux/tpm.h | 6 ++++--
> 4 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb7e109..e94148b8e180 100644
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -295,6 +295,7 @@ static int tpm_class_shutdown(struct device *dev)
> {
> struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
>
> + wait_event_idle(chip->waitq, !atomic_read(&chip->refcount));
> down_write(&chip->ops_sem);
> if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> if (!tpm_chip_start(chip)) {
> @@ -330,6 +331,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>
> mutex_init(&chip->tpm_mutex);
> init_rwsem(&chip->ops_sem);
> + init_waitqueue_head(&chip->waitq);
>
> chip->ops = ops;
>
> diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
> index e2c0baa69fef..8558f0f7382c 100644
> +++ b/drivers/char/tpm/tpm-dev.c
> @@ -19,27 +19,32 @@ static int tpm_open(struct inode *inode, struct file *file)
> {
> struct tpm_chip *chip;
> struct file_priv *priv;
> + int ret = 0;
>
> chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
>
> /* It's assured that the chip will be opened just once,
> - * by the check of is_open variable, which is protected
> - * by driver_lock. */
> - if (test_and_set_bit(0, &chip->is_open)) {
> + * by the check of the chip reference count.
> + */
> + if (atomic_fetch_inc(&chip->refcount)) {
Use a refcount_t for all this
> @@ -39,6 +40,8 @@ static int tpmrm_release(struct inode *inode, struct file *file)
>
> tpm_common_release(file, fpriv);
> tpm2_del_space(fpriv->chip, &priv->space);
> + atomic_dec(&fpriv->chip->refcount);
> + wake_up_all(&fpriv->chip->waitq);
The usual pattern is
if (refcount_dec_and_test(&fpriv->chip->refcount))
wake_up_all(&fpriv->chip->waitq);
But this seems like madness, this blocks tpm_class_shutdown until
userspace closes a file descriptor, can't do it.
You need to have tpm_class_shutdown() remove the ops from the still
open FD and have that FD start returning -EIO when the ops are gone,
which is what the ops lock is already for.
Jason
On Tue, 2020-12-15 at 16:38 +0300, Sergey Temerkhanov wrote:
> Avoid race condition at shutdown by shutting downn the TPM 2.0
> devices synchronously. This eliminates the condition when the
> shutdown sequence sets chip->ops to NULL leading to the following:
>
> [ 1586.593561][ T8669] tpm2_del_space+0x28/0x73
> [ 1586.598718][ T8669] tpmrm_release+0x27/0x33wq
> [ 1586.603774][ T8669] __fput+0x109/0x1d
> [ 1586.608380][ T8669] task_work_run+0x7c/0x90
> [ 1586.613414][ T8669] prepare_exit_to_usermode+0xb8/0x128
> [ 1586.619522][ T8669] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 1586.626068][ T8669] RIP: 0033:0x4cb4bb
An actual bug report would have been helpful. However, from this trace
it's easy to deduce that tpm2_del_space() didn't get converted to the
get/put of the chip ops ... it's still trying to do its own half arsed
thing with tpm_chip_start() and the mutex. So isn't a much simpler fix
simply to convert it as below? compile tested only, but if you can
test it out I'll send a proper patch.
James
---
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 784b8b3cb903..0c0cd225046f 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -58,12 +58,12 @@ 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)) {
+
+ if (tpm_try_get_ops(chip) == 0) {
tpm2_flush_sessions(chip, space);
- tpm_chip_stop(chip);
+ tpm_put_ops(chip);
}
- mutex_unlock(&chip->tpm_mutex);
+
kfree(space->context_buf);
kfree(space->session_buf);
}
On Tue, 2020-12-15 at 10:51 -0800, James Bottomley wrote:
> On Tue, 2020-12-15 at 16:38 +0300, Sergey Temerkhanov wrote:
> > Avoid race condition at shutdown by shutting downn the TPM 2.0
> > devices synchronously. This eliminates the condition when the
> > shutdown sequence sets chip->ops to NULL leading to the following:
> >
> > [ 1586.593561][ T8669] tpm2_del_space+0x28/0x73
> > [ 1586.598718][ T8669] tpmrm_release+0x27/0x33wq
> > [ 1586.603774][ T8669] __fput+0x109/0x1d
> > [ 1586.608380][ T8669] task_work_run+0x7c/0x90
> > [ 1586.613414][ T8669] prepare_exit_to_usermode+0xb8/0x128
> > [ 1586.619522][ T8669] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [ 1586.626068][ T8669] RIP: 0033:0x4cb4bb
>
> An actual bug report would have been helpful. However, from this
> trace it's easy to deduce that tpm2_del_space() didn't get converted
> to the get/put of the chip ops ... it's still trying to do its own
> half arsed thing with tpm_chip_start() and the mutex. So isn't a
> much simpler fix simply to convert it as below? compile tested only,
> but if you can test it out I'll send a proper patch.
I got this booted and running here, so I know it works. What I still
need to know is does it fix your problem?
James
On Mon, 2022-03-07 at 17:41 +0200, Jarkko Sakkinen wrote:
[...]
> James, would it possible for you to construct a proper patch from
> this and send it so we could include it to the next PR (use my tree
> as baseline)?
Sure, There's not really any identifiable patch for a fixes tag, since
the race really always existed.
How about the below.
James
-------------------8>8>8><8<8<8------------------
From 3e0e640e47e5728b68693c5d45bf3cdd0bff48ca Mon Sep 17 00:00:00 2001
From: James Bottomley <[email protected]>
Date: Mon, 7 Mar 2022 11:16:55 -0500
Subject: [PATCH] tpm: use try_get_ops() in tpm-space.c
As part of the series conversion to remove nested TPM operations:
https://lore.kernel.org/all/[email protected]/
exposure of the chip->tpm_mutex was removed from much of the upper
level code. In this conversion, tpm2_del_space() was missed. This
didn't matter much because it's usually called closely after a
converted operation, so there's only a very tiny race window where the
chip can be removed before the space flushing is done which causes a
NULL deref on the mutex. However, there are reports of this window
being hit in practice, so fix this by converting tpm2_del_space() to
use tpm_try_get_ops(), which performs all the teardown checks before
acquring the mutex.
Signed-off-by: James Bottomley <[email protected]>
---
drivers/char/tpm/tpm2-space.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
index 265ec72b1d81..ffb35f0154c1 100644
--- a/drivers/char/tpm/tpm2-space.c
+++ b/drivers/char/tpm/tpm2-space.c
@@ -58,12 +58,12 @@ 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)) {
+
+ if (tpm_try_get_ops(chip) == 0) {
tpm2_flush_sessions(chip, space);
- tpm_chip_stop(chip);
+ tpm_put_ops(chip);
}
- mutex_unlock(&chip->tpm_mutex);
+
kfree(space->context_buf);
kfree(space->session_buf);
}
--
2.34.1
On Mon, Mar 07, 2022 at 06:44:17PM +0200, Jarkko Sakkinen wrote:
> On Mon, Mar 07, 2022 at 11:22:27AM -0500, James Bottomley wrote:
> > On Mon, 2022-03-07 at 17:41 +0200, Jarkko Sakkinen wrote:
> > [...]
> > > James, would it possible for you to construct a proper patch from
> > > this and send it so we could include it to the next PR (use my tree
> > > as baseline)?
> >
> > Sure, There's not really any identifiable patch for a fixes tag, since
> > the race really always existed.
> >
> > How about the below.
> >
> > James
> >
> > -------------------8>8>8><8<8<8------------------
> >
> > From 3e0e640e47e5728b68693c5d45bf3cdd0bff48ca Mon Sep 17 00:00:00 2001
> > From: James Bottomley <[email protected]>
> > Date: Mon, 7 Mar 2022 11:16:55 -0500
> > Subject: [PATCH] tpm: use try_get_ops() in tpm-space.c
> >
> > As part of the series conversion to remove nested TPM operations:
> >
> > https://lore.kernel.org/all/[email protected]/
> >
> > exposure of the chip->tpm_mutex was removed from much of the upper
> > level code. In this conversion, tpm2_del_space() was missed. This
> > didn't matter much because it's usually called closely after a
> > converted operation, so there's only a very tiny race window where the
> > chip can be removed before the space flushing is done which causes a
> > NULL deref on the mutex. However, there are reports of this window
> > being hit in practice, so fix this by converting tpm2_del_space() to
> > use tpm_try_get_ops(), which performs all the teardown checks before
> > acquring the mutex.
> >
> > Signed-off-by: James Bottomley <[email protected]>
> > ---
> > drivers/char/tpm/tpm2-space.c | 8 ++++----
> > 1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> > index 265ec72b1d81..ffb35f0154c1 100644
> > --- a/drivers/char/tpm/tpm2-space.c
> > +++ b/drivers/char/tpm/tpm2-space.c
> > @@ -58,12 +58,12 @@ 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)) {
> > +
> > + if (tpm_try_get_ops(chip) == 0) {
> > tpm2_flush_sessions(chip, space);
> > - tpm_chip_stop(chip);
> > + tpm_put_ops(chip);
> > }
> > - mutex_unlock(&chip->tpm_mutex);
> > +
> > kfree(space->context_buf);
> > kfree(space->session_buf);
> > }
> > --
> > 2.34.1
> >
> >
>
> Thank you! LGTM.
>
> Reviewed-by: Jarkko Sakkinen <[email protected]>
>
> BR, Jarkko
If possible, can you send this an identifiable patch (separate email)
with my reviewed-by applied, and I'll take it from there (i.e. it's
then available all trackers such patchwork etc.)?
BR, Jarkko
On Mon, Mar 07, 2022 at 11:22:27AM -0500, James Bottomley wrote:
> On Mon, 2022-03-07 at 17:41 +0200, Jarkko Sakkinen wrote:
> [...]
> > James, would it possible for you to construct a proper patch from
> > this and send it so we could include it to the next PR (use my tree
> > as baseline)?
>
> Sure, There's not really any identifiable patch for a fixes tag, since
> the race really always existed.
>
> How about the below.
>
> James
>
> -------------------8>8>8><8<8<8------------------
>
> From 3e0e640e47e5728b68693c5d45bf3cdd0bff48ca Mon Sep 17 00:00:00 2001
> From: James Bottomley <[email protected]>
> Date: Mon, 7 Mar 2022 11:16:55 -0500
> Subject: [PATCH] tpm: use try_get_ops() in tpm-space.c
>
> As part of the series conversion to remove nested TPM operations:
>
> https://lore.kernel.org/all/[email protected]/
>
> exposure of the chip->tpm_mutex was removed from much of the upper
> level code. In this conversion, tpm2_del_space() was missed. This
> didn't matter much because it's usually called closely after a
> converted operation, so there's only a very tiny race window where the
> chip can be removed before the space flushing is done which causes a
> NULL deref on the mutex. However, there are reports of this window
> being hit in practice, so fix this by converting tpm2_del_space() to
> use tpm_try_get_ops(), which performs all the teardown checks before
> acquring the mutex.
>
> Signed-off-by: James Bottomley <[email protected]>
> ---
> drivers/char/tpm/tpm2-space.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 265ec72b1d81..ffb35f0154c1 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -58,12 +58,12 @@ 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)) {
> +
> + if (tpm_try_get_ops(chip) == 0) {
> tpm2_flush_sessions(chip, space);
> - tpm_chip_stop(chip);
> + tpm_put_ops(chip);
> }
> - mutex_unlock(&chip->tpm_mutex);
> +
> kfree(space->context_buf);
> kfree(space->session_buf);
> }
> --
> 2.34.1
>
>
Thank you! LGTM.
Reviewed-by: Jarkko Sakkinen <[email protected]>
BR, Jarkko
On Tue, Dec 15, 2020 at 10:51:43AM -0800, James Bottomley wrote:
> On Tue, 2020-12-15 at 16:38 +0300, Sergey Temerkhanov wrote:
> > Avoid race condition at shutdown by shutting downn the TPM 2.0
> > devices synchronously. This eliminates the condition when the
> > shutdown sequence sets chip->ops to NULL leading to the following:
> >
> > [ 1586.593561][ T8669] tpm2_del_space+0x28/0x73
> > [ 1586.598718][ T8669] tpmrm_release+0x27/0x33wq
> > [ 1586.603774][ T8669] __fput+0x109/0x1d
> > [ 1586.608380][ T8669] task_work_run+0x7c/0x90
> > [ 1586.613414][ T8669] prepare_exit_to_usermode+0xb8/0x128
> > [ 1586.619522][ T8669] entry_SYSCALL_64_after_hwframe+0x44/0xa9
> > [ 1586.626068][ T8669] RIP: 0033:0x4cb4bb
>
> An actual bug report would have been helpful. However, from this trace
> it's easy to deduce that tpm2_del_space() didn't get converted to the
> get/put of the chip ops ... it's still trying to do its own half arsed
> thing with tpm_chip_start() and the mutex. So isn't a much simpler fix
> simply to convert it as below? compile tested only, but if you can
> test it out I'll send a proper patch.
>
> James
>
> ---
>
> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 784b8b3cb903..0c0cd225046f 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -58,12 +58,12 @@ 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)) {
> +
> + if (tpm_try_get_ops(chip) == 0) {
> tpm2_flush_sessions(chip, space);
> - tpm_chip_stop(chip);
> + tpm_put_ops(chip);
> }
> - mutex_unlock(&chip->tpm_mutex);
> +
> kfree(space->context_buf);
> kfree(space->session_buf);
> }
>
James, would it possible for you to construct a proper patch from this and
send it so we could include it to the next PR (use my tree as baseline)?
BR, Jarkko