[PATCH] net/9p/usbg: dont call usb9pfs_clear_tx if client is not connected

[PATCH] net/9p/usbg: dont call usb9pfs_clear_tx if client is not connected

[Michael Grzeschik]

When the client is not Connected it is not valid to call
usb9pfs_clear_tx since the endpoints are not even allocated. By running
into p9_usbg_close in that case we would dereference the in_req which is
NULL when the client->status is Disconnected. Fix that by leaving
usb9pfs_clear_tx immediately if the state is wrong.

We also update the client->status after the for usb9pfs_clear_tx to
check for the actual state when running from p9_usbg_close.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 net/9p/trans_usbg.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c
index 975b76839dca1..64a5209943dbc 100644
--- a/net/9p/trans_usbg.c
+++ b/net/9p/trans_usbg.c
@@ -417,6 +417,10 @@ static void usb9pfs_clear_tx(struct f_usb9pfs *usb9pfs)
 {
 	struct p9_req_t *req;
 
+	/* we are not allocated - return */
+	if (usb9pfs->client->status != Connected)
+		return;
+
 	guard(spinlock_irqsave)(&usb9pfs->lock);
 
 	req = usb9pfs->in_req->context;
@@ -442,10 +446,10 @@ static void p9_usbg_close(struct p9_client *client)
 	if (!usb9pfs)
 		return;
 
-	client->status = Disconnected;
-
 	usb9pfs_clear_tx(usb9pfs);
 
+	client->status = Disconnected;
+
 	opts = container_of(usb9pfs->function.fi,
 			    struct f_usb9pfs_opts, func_inst);
 

---
base-commit: 68d4209158f43a558c5553ea95ab0c8975eab18c
change-id: 20240929-fixes9p-5d618bbe6d6b

Best regards,
-- 
Michael Grzeschik <m.grzeschik@pengutronix.de>

Re: [PATCH] net/9p/usbg: dont call usb9pfs_clear_tx if client is not connected

[Michael Grzeschik]

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Please drop this patch for now. I will have to do some more testing
regarding the prompt connect mount and disconnect state changes
and will come back with a proper solution.

On Sun, Sep 29, 2024 at 09:22:55PM +0200, Michael Grzeschik wrote:
>When the client is not Connected it is not valid to call
>usb9pfs_clear_tx since the endpoints are not even allocated. By running
>into p9_usbg_close in that case we would dereference the in_req which is
>NULL when the client->status is Disconnected. Fix that by leaving
>usb9pfs_clear_tx immediately if the state is wrong.
>
>We also update the client->status after the for usb9pfs_clear_tx to
>check for the actual state when running from p9_usbg_close.
>
>Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
>---
> net/9p/trans_usbg.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c
>index 975b76839dca1..64a5209943dbc 100644
>--- a/net/9p/trans_usbg.c
>+++ b/net/9p/trans_usbg.c
>@@ -417,6 +417,10 @@ static void usb9pfs_clear_tx(struct f_usb9pfs *usb9pfs)
> {
> 	struct p9_req_t *req;
>
>+	/* we are not allocated - return */
>+	if (usb9pfs->client->status != Connected)
>+		return;
>+
> 	guard(spinlock_irqsave)(&usb9pfs->lock);
>
> 	req = usb9pfs->in_req->context;
>@@ -442,10 +446,10 @@ static void p9_usbg_close(struct p9_client *client)
> 	if (!usb9pfs)
> 		return;
>
>-	client->status = Disconnected;
>-
> 	usb9pfs_clear_tx(usb9pfs);
>
>+	client->status = Disconnected;
>+
> 	opts = container_of(usb9pfs->function.fi,
> 			    struct f_usb9pfs_opts, func_inst);
>
>
>---
>base-commit: 68d4209158f43a558c5553ea95ab0c8975eab18c
>change-id: 20240929-fixes9p-5d618bbe6d6b
>
>Best regards,
>-- 
>Michael Grzeschik <m.grzeschik@pengutronix.de>
>
>

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