* [PATCH v2 1/2] usb: typec: ucsi: displayport: Fix deadlock
[not found] <20250424084429.3220757-1-akuchynski@chromium.org>
@ 2025-04-24 8:44 ` Andrei Kuchynski
2025-04-28 13:23 ` Heikki Krogerus
2025-04-24 8:44 ` [PATCH v2 2/2] usb: typec: ucsi: displayport: Fix NULL pointer access Andrei Kuchynski
1 sibling, 1 reply; 4+ messages in thread
From: Andrei Kuchynski @ 2025-04-24 8:44 UTC (permalink / raw)
To: Heikki Krogerus, Greg Kroah-Hartman, Jameson Thies,
Abhishek Pandit-Subedi, Benson Leung, Dmitry Baryshkov, Diogo Ivo,
Pooja Katiyar, Madhu M
Cc: linux-usb, linux-kernel, Andrei Kuchynski, stable
This patch introduces the ucsi_con_mutex_lock / ucsi_con_mutex_unlock
functions to the UCSI driver. ucsi_con_mutex_lock ensures the connector
mutex is only locked if a connection is established and the partner pointer
is valid. This resolves a deadlock scenario where
ucsi_displayport_remove_partner holds con->mutex waiting for
dp_altmode_work to complete while dp_altmode_work attempts to acquire it.
Cc: stable@vger.kernel.org
Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
---
drivers/usb/typec/ucsi/displayport.c | 19 +++++++++-------
drivers/usb/typec/ucsi/ucsi.c | 34 ++++++++++++++++++++++++++++
drivers/usb/typec/ucsi/ucsi.h | 2 ++
3 files changed, 47 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index 420af5139c70..acd053d4e38c 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -54,7 +54,8 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo)
u8 cur = 0;
int ret;
- mutex_lock(&dp->con->lock);
+ if (!ucsi_con_mutex_lock(dp->con))
+ return -ENOTCONN;
if (!dp->override && dp->initialized) {
const struct typec_altmode *p = typec_altmode_get_partner(alt);
@@ -100,7 +101,7 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo)
schedule_work(&dp->work);
ret = 0;
err_unlock:
- mutex_unlock(&dp->con->lock);
+ ucsi_con_mutex_unlock(dp->con);
return ret;
}
@@ -112,7 +113,8 @@ static int ucsi_displayport_exit(struct typec_altmode *alt)
u64 command;
int ret = 0;
- mutex_lock(&dp->con->lock);
+ if (!ucsi_con_mutex_lock(dp->con))
+ return -ENOTCONN;
if (!dp->override) {
const struct typec_altmode *p = typec_altmode_get_partner(alt);
@@ -144,7 +146,7 @@ static int ucsi_displayport_exit(struct typec_altmode *alt)
schedule_work(&dp->work);
out_unlock:
- mutex_unlock(&dp->con->lock);
+ ucsi_con_mutex_unlock(dp->con);
return ret;
}
@@ -202,20 +204,21 @@ static int ucsi_displayport_vdm(struct typec_altmode *alt,
int cmd = PD_VDO_CMD(header);
int svdm_version;
- mutex_lock(&dp->con->lock);
+ if (!ucsi_con_mutex_lock(dp->con))
+ return -ENOTCONN;
if (!dp->override && dp->initialized) {
const struct typec_altmode *p = typec_altmode_get_partner(alt);
dev_warn(&p->dev,
"firmware doesn't support alternate mode overriding\n");
- mutex_unlock(&dp->con->lock);
+ ucsi_con_mutex_unlock(dp->con);
return -EOPNOTSUPP;
}
svdm_version = typec_altmode_get_svdm_version(alt);
if (svdm_version < 0) {
- mutex_unlock(&dp->con->lock);
+ ucsi_con_mutex_unlock(dp->con);
return svdm_version;
}
@@ -259,7 +262,7 @@ static int ucsi_displayport_vdm(struct typec_altmode *alt,
break;
}
- mutex_unlock(&dp->con->lock);
+ ucsi_con_mutex_unlock(dp->con);
return 0;
}
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index e8c7e9dc4930..01ce858a1a2b 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1922,6 +1922,40 @@ void ucsi_set_drvdata(struct ucsi *ucsi, void *data)
}
EXPORT_SYMBOL_GPL(ucsi_set_drvdata);
+/**
+ * ucsi_con_mutex_lock - Acquire the connector mutex
+ * @con: The connector interface to lock
+ *
+ * Returns true on success, false if the connector is disconnected
+ */
+bool ucsi_con_mutex_lock(struct ucsi_connector *con)
+{
+ bool mutex_locked = false;
+ bool connected = true;
+
+ while (connected && !mutex_locked) {
+ mutex_locked = mutex_trylock(&con->lock) != 0;
+ connected = UCSI_CONSTAT(con, CONNECTED);
+ if (connected && !mutex_locked)
+ msleep(20);
+ }
+
+ connected = connected && con->partner;
+ if (!connected && mutex_locked)
+ mutex_unlock(&con->lock);
+
+ return connected;
+}
+
+/**
+ * ucsi_con_mutex_unlock - Release the connector mutex
+ * @con: The connector interface to unlock
+ */
+void ucsi_con_mutex_unlock(struct ucsi_connector *con)
+{
+ mutex_unlock(&con->lock);
+}
+
/**
* ucsi_create - Allocate UCSI instance
* @dev: Device interface to the PPM (Platform Policy Manager)
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index 3a2c1762bec1..9c5278a0c5d4 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -94,6 +94,8 @@ int ucsi_register(struct ucsi *ucsi);
void ucsi_unregister(struct ucsi *ucsi);
void *ucsi_get_drvdata(struct ucsi *ucsi);
void ucsi_set_drvdata(struct ucsi *ucsi, void *data);
+bool ucsi_con_mutex_lock(struct ucsi_connector *con);
+void ucsi_con_mutex_unlock(struct ucsi_connector *con);
void ucsi_connector_change(struct ucsi *ucsi, u8 num);
--
2.49.0.805.g082f7c87e0-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v2 2/2] usb: typec: ucsi: displayport: Fix NULL pointer access
[not found] <20250424084429.3220757-1-akuchynski@chromium.org>
2025-04-24 8:44 ` [PATCH v2 1/2] usb: typec: ucsi: displayport: Fix deadlock Andrei Kuchynski
@ 2025-04-24 8:44 ` Andrei Kuchynski
2025-04-24 16:20 ` Benson Leung
1 sibling, 1 reply; 4+ messages in thread
From: Andrei Kuchynski @ 2025-04-24 8:44 UTC (permalink / raw)
To: Heikki Krogerus, Greg Kroah-Hartman, Jameson Thies,
Abhishek Pandit-Subedi, Benson Leung, Dmitry Baryshkov, Diogo Ivo,
Pooja Katiyar, Madhu M
Cc: linux-usb, linux-kernel, Andrei Kuchynski, stable
This patch ensures that the UCSI driver waits for all pending tasks in the
ucsi_displayport_work workqueue to finish executing before proceeding with
the partner removal.
Cc: stable@vger.kernel.org
Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
drivers/usb/typec/ucsi/displayport.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
index acd053d4e38c..8aae80b457d7 100644
--- a/drivers/usb/typec/ucsi/displayport.c
+++ b/drivers/usb/typec/ucsi/displayport.c
@@ -299,6 +299,8 @@ void ucsi_displayport_remove_partner(struct typec_altmode *alt)
if (!dp)
return;
+ cancel_work_sync(&dp->work);
+
dp->data.conf = 0;
dp->data.status = 0;
dp->initialized = false;
--
2.49.0.805.g082f7c87e0-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2 2/2] usb: typec: ucsi: displayport: Fix NULL pointer access
2025-04-24 8:44 ` [PATCH v2 2/2] usb: typec: ucsi: displayport: Fix NULL pointer access Andrei Kuchynski
@ 2025-04-24 16:20 ` Benson Leung
0 siblings, 0 replies; 4+ messages in thread
From: Benson Leung @ 2025-04-24 16:20 UTC (permalink / raw)
To: Andrei Kuchynski
Cc: Heikki Krogerus, Greg Kroah-Hartman, Jameson Thies,
Abhishek Pandit-Subedi, Benson Leung, Dmitry Baryshkov, Diogo Ivo,
Pooja Katiyar, Madhu M, linux-usb, linux-kernel, stable
[-- Attachment #1: Type: text/plain, Size: 1142 bytes --]
On Thu, Apr 24, 2025 at 08:44:29AM +0000, Andrei Kuchynski wrote:
> This patch ensures that the UCSI driver waits for all pending tasks in the
> ucsi_displayport_work workqueue to finish executing before proceeding with
> the partner removal.
>
> Cc: stable@vger.kernel.org
> Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
> Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
> ---
> drivers/usb/typec/ucsi/displayport.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
> index acd053d4e38c..8aae80b457d7 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -299,6 +299,8 @@ void ucsi_displayport_remove_partner(struct typec_altmode *alt)
> if (!dp)
> return;
>
> + cancel_work_sync(&dp->work);
> +
> dp->data.conf = 0;
> dp->data.status = 0;
> dp->initialized = false;
> --
> 2.49.0.805.g082f7c87e0-goog
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2 1/2] usb: typec: ucsi: displayport: Fix deadlock
2025-04-24 8:44 ` [PATCH v2 1/2] usb: typec: ucsi: displayport: Fix deadlock Andrei Kuchynski
@ 2025-04-28 13:23 ` Heikki Krogerus
0 siblings, 0 replies; 4+ messages in thread
From: Heikki Krogerus @ 2025-04-28 13:23 UTC (permalink / raw)
To: Andrei Kuchynski
Cc: Greg Kroah-Hartman, Jameson Thies, Abhishek Pandit-Subedi,
Benson Leung, Dmitry Baryshkov, Diogo Ivo, Pooja Katiyar, Madhu M,
linux-usb, linux-kernel, stable
On Thu, Apr 24, 2025 at 08:44:28AM +0000, Andrei Kuchynski wrote:
> This patch introduces the ucsi_con_mutex_lock / ucsi_con_mutex_unlock
> functions to the UCSI driver. ucsi_con_mutex_lock ensures the connector
> mutex is only locked if a connection is established and the partner pointer
> is valid. This resolves a deadlock scenario where
> ucsi_displayport_remove_partner holds con->mutex waiting for
> dp_altmode_work to complete while dp_altmode_work attempts to acquire it.
>
> Cc: stable@vger.kernel.org
> Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode")
> Signed-off-by: Andrei Kuchynski <akuchynski@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
> drivers/usb/typec/ucsi/displayport.c | 19 +++++++++-------
> drivers/usb/typec/ucsi/ucsi.c | 34 ++++++++++++++++++++++++++++
> drivers/usb/typec/ucsi/ucsi.h | 2 ++
> 3 files changed, 47 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
> index 420af5139c70..acd053d4e38c 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -54,7 +54,8 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo)
> u8 cur = 0;
> int ret;
>
> - mutex_lock(&dp->con->lock);
> + if (!ucsi_con_mutex_lock(dp->con))
> + return -ENOTCONN;
>
> if (!dp->override && dp->initialized) {
> const struct typec_altmode *p = typec_altmode_get_partner(alt);
> @@ -100,7 +101,7 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo)
> schedule_work(&dp->work);
> ret = 0;
> err_unlock:
> - mutex_unlock(&dp->con->lock);
> + ucsi_con_mutex_unlock(dp->con);
>
> return ret;
> }
> @@ -112,7 +113,8 @@ static int ucsi_displayport_exit(struct typec_altmode *alt)
> u64 command;
> int ret = 0;
>
> - mutex_lock(&dp->con->lock);
> + if (!ucsi_con_mutex_lock(dp->con))
> + return -ENOTCONN;
>
> if (!dp->override) {
> const struct typec_altmode *p = typec_altmode_get_partner(alt);
> @@ -144,7 +146,7 @@ static int ucsi_displayport_exit(struct typec_altmode *alt)
> schedule_work(&dp->work);
>
> out_unlock:
> - mutex_unlock(&dp->con->lock);
> + ucsi_con_mutex_unlock(dp->con);
>
> return ret;
> }
> @@ -202,20 +204,21 @@ static int ucsi_displayport_vdm(struct typec_altmode *alt,
> int cmd = PD_VDO_CMD(header);
> int svdm_version;
>
> - mutex_lock(&dp->con->lock);
> + if (!ucsi_con_mutex_lock(dp->con))
> + return -ENOTCONN;
>
> if (!dp->override && dp->initialized) {
> const struct typec_altmode *p = typec_altmode_get_partner(alt);
>
> dev_warn(&p->dev,
> "firmware doesn't support alternate mode overriding\n");
> - mutex_unlock(&dp->con->lock);
> + ucsi_con_mutex_unlock(dp->con);
> return -EOPNOTSUPP;
> }
>
> svdm_version = typec_altmode_get_svdm_version(alt);
> if (svdm_version < 0) {
> - mutex_unlock(&dp->con->lock);
> + ucsi_con_mutex_unlock(dp->con);
> return svdm_version;
> }
>
> @@ -259,7 +262,7 @@ static int ucsi_displayport_vdm(struct typec_altmode *alt,
> break;
> }
>
> - mutex_unlock(&dp->con->lock);
> + ucsi_con_mutex_unlock(dp->con);
>
> return 0;
> }
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index e8c7e9dc4930..01ce858a1a2b 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1922,6 +1922,40 @@ void ucsi_set_drvdata(struct ucsi *ucsi, void *data)
> }
> EXPORT_SYMBOL_GPL(ucsi_set_drvdata);
>
> +/**
> + * ucsi_con_mutex_lock - Acquire the connector mutex
> + * @con: The connector interface to lock
> + *
> + * Returns true on success, false if the connector is disconnected
> + */
> +bool ucsi_con_mutex_lock(struct ucsi_connector *con)
> +{
> + bool mutex_locked = false;
> + bool connected = true;
> +
> + while (connected && !mutex_locked) {
> + mutex_locked = mutex_trylock(&con->lock) != 0;
> + connected = UCSI_CONSTAT(con, CONNECTED);
> + if (connected && !mutex_locked)
> + msleep(20);
> + }
> +
> + connected = connected && con->partner;
> + if (!connected && mutex_locked)
> + mutex_unlock(&con->lock);
> +
> + return connected;
> +}
> +
> +/**
> + * ucsi_con_mutex_unlock - Release the connector mutex
> + * @con: The connector interface to unlock
> + */
> +void ucsi_con_mutex_unlock(struct ucsi_connector *con)
> +{
> + mutex_unlock(&con->lock);
> +}
> +
> /**
> * ucsi_create - Allocate UCSI instance
> * @dev: Device interface to the PPM (Platform Policy Manager)
> diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
> index 3a2c1762bec1..9c5278a0c5d4 100644
> --- a/drivers/usb/typec/ucsi/ucsi.h
> +++ b/drivers/usb/typec/ucsi/ucsi.h
> @@ -94,6 +94,8 @@ int ucsi_register(struct ucsi *ucsi);
> void ucsi_unregister(struct ucsi *ucsi);
> void *ucsi_get_drvdata(struct ucsi *ucsi);
> void ucsi_set_drvdata(struct ucsi *ucsi, void *data);
> +bool ucsi_con_mutex_lock(struct ucsi_connector *con);
> +void ucsi_con_mutex_unlock(struct ucsi_connector *con);
>
> void ucsi_connector_change(struct ucsi *ucsi, u8 num);
>
> --
> 2.49.0.805.g082f7c87e0-goog
--
heikki
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-04-28 13:23 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <20250424084429.3220757-1-akuchynski@chromium.org>
2025-04-24 8:44 ` [PATCH v2 1/2] usb: typec: ucsi: displayport: Fix deadlock Andrei Kuchynski
2025-04-28 13:23 ` Heikki Krogerus
2025-04-24 8:44 ` [PATCH v2 2/2] usb: typec: ucsi: displayport: Fix NULL pointer access Andrei Kuchynski
2025-04-24 16:20 ` Benson Leung
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).