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usb: typec: class: fix typec_altmode_put_partner to put plugs

PATCH In review RD Babiera 3 participants 3 messages Jan 3, 2024 – Jan 4, 2024

Subsystems (3)
Stable branch USB USB Type-C class
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RD Babiera

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#0 lore raw

PATCH v4 1/1 usb: typec: class: fix typec_altmode_put_partner to put plugs

When typec_altmode_put_partner is called by a plug altmode upon release, the port altmode the plug belongs to will not remove its reference to the plug. The check to see if the altmode being released is a plug evaluates against the released altmode's partner instead of the calling altmode, so change adev in typec_altmode_put_partner to properly refer to the altmode being released.

Because typec_altmode_set_partner calls get_device() on the port altmode, add partner_adev that points to the port altmode in typec_put_partner to call put_device() on. typec_altmode_set_partner is not called for port altmodes, so add a check in typec_altmode_release to prevent typec_altmode_put_partner() calls on port altmode release.

Fixes 8a37d87d72f0 ("usb: typec: Bus type for alternate modes")
Cc [email protected]
Co-developed-by Christian A. Ehrhardt <[email protected]>
Signed-off-by Christian A. Ehrhardt <[email protected]>
Signed-off-by RD Babiera <[email protected]>

---
Changes since v3:
* added partner_adev to properly put_device() on port altmode.

---
 drivers/usb/typec/class.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
drivers/usb/typec/class.c +6 -3
index 4d11f2b536fa..015aa9253353 100644
@@ -263,11 +263,13 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 {
 	struct altmode *partner = altmode->partner;
 	struct typec_altmode *adev;
+	struct typec_altmode *partner_adev;
 
 	if (!partner)
 		return;
 
-	adev = &partner->adev;
+	adev = &altmode->adev;
+	partner_adev = &partner->adev;
 
 	if (is_typec_plug(adev->dev.parent)) {
 		struct typec_plug *plug = to_typec_plug(adev->dev.parent);

@@ -276,7 +278,7 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 	} else {
 		partner->partner = NULL;
 	}
-	put_device(&adev->dev);
+	put_device(&partner_adev->dev);
 }
 
 /**

@@ -497,7 +499,8 @@ static void typec_altmode_release(struct device *dev)
 {
 	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 
-	typec_altmode_put_partner(alt);
+	if (!is_typec_port(dev->parent))
+		typec_altmode_put_partner(alt);
 
 	altmode_id_remove(alt->adev.dev.parent, alt->id);
 	kfree(alt);

base-commit: e7d3b9f28654dbfce7e09f8028210489adaf6a33

Signature · 1 line
2.43.0.472.g3155946c3a-goog
Tested-by on v4 1/1
#1 lore raw
Quoted 13 lines · RD Babiera

When typec_altmode_put_partner is called by a plug altmode upon release, the port altmode the plug belongs to will not remove its reference to the plug. The check to see if the altmode being released is a plug evaluates against the released altmode's partner instead of the calling altmode, so change adev in typec_altmode_put_partner to properly refer to the altmode being released.

Because typec_altmode_set_partner calls get_device() on the port altmode, add partner_adev that points to the port altmode in typec_put_partner to call put_device() on. typec_altmode_set_partner is not called for port altmodes, so add a check in typec_altmode_release to prevent typec_altmode_put_partner() calls on port altmode release.

Quoted 5 lines
Fixes 8a37d87d72f0 ("usb: typec: Bus type for alternate modes")
Cc [email protected]
Co-developed-by Christian A. Ehrhardt <[email protected]>
Signed-off-by Christian A. Ehrhardt <[email protected]>
Signed-off-by RD Babiera <[email protected]>

I was able to reproduce the bug of the original report from here

https://lore.kernel.org/all/CAP-bSRb3SXpgo_BEdqZB-p1K5625fMegRZ17ZkPE1J8ZYgEHDg@mail.gmail.com/

(with some hacks) and verified that this change on top of a revert of b17b7fe6dd (already in linux-usb) fixes the original bug. The test does not excercise the code that deals with cable plugs, though. Thus:

Tested-by Christian A. Ehrhardt <[email protected]>

Given that this is otherwise a 6.7 regression it might be a good idea to consider this for 6.7?

Quoted 46 lines

---
Changes since v3:
* added partner_adev to properly put_device() on port altmode.

---
 drivers/usb/typec/class.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
drivers/usb/typec/class.c +6 -3
index 4d11f2b536fa..015aa9253353 100644
@@ -263,11 +263,13 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 {
 	struct altmode *partner = altmode->partner;
 	struct typec_altmode *adev;
+	struct typec_altmode *partner_adev;
 
 	if (!partner)
 		return;
 
-	adev = &partner->adev;
+	adev = &altmode->adev;
+	partner_adev = &partner->adev;
 
 	if (is_typec_plug(adev->dev.parent)) {
 		struct typec_plug *plug = to_typec_plug(adev->dev.parent);

@@ -276,7 +278,7 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 	} else {
 		partner->partner = NULL;
 	}
-	put_device(&adev->dev);
+	put_device(&partner_adev->dev);
 }
 
 /**

@@ -497,7 +499,8 @@ static void typec_altmode_release(struct device *dev)
 {
 	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 
-	typec_altmode_put_partner(alt);
+	if (!is_typec_port(dev->parent))
+		typec_altmode_put_partner(alt);
 
 	altmode_id_remove(alt->adev.dev.parent, alt->id);
 	kfree(alt);
Quoted 5 lines

base-commit: e7d3b9f28654dbfce7e09f8028210489adaf6a33

Signature · 1 line
2.43.0.472.g3155946c3a-goog

regards Christian

maintainer Acked-by on v4 1/1
#2 lore raw
In reply to RD Babiera
Quoted 13 lines · RD Babiera

When typec_altmode_put_partner is called by a plug altmode upon release, the port altmode the plug belongs to will not remove its reference to the plug. The check to see if the altmode being released is a plug evaluates against the released altmode's partner instead of the calling altmode, so change adev in typec_altmode_put_partner to properly refer to the altmode being released.

Because typec_altmode_set_partner calls get_device() on the port altmode, add partner_adev that points to the port altmode in typec_put_partner to call put_device() on. typec_altmode_set_partner is not called for port altmodes, so add a check in typec_altmode_release to prevent typec_altmode_put_partner() calls on port altmode release.

Quoted 5 lines
Fixes 8a37d87d72f0 ("usb: typec: Bus type for alternate modes")
Cc [email protected]
Co-developed-by Christian A. Ehrhardt <[email protected]>
Signed-off-by Christian A. Ehrhardt <[email protected]>
Signed-off-by RD Babiera <[email protected]>
Acked-by Heikki Krogerus <[email protected]>
Quoted 49 lines

---
Changes since v3:
* added partner_adev to properly put_device() on port altmode.

---
 drivers/usb/typec/class.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)
drivers/usb/typec/class.c +6 -3
index 4d11f2b536fa..015aa9253353 100644
@@ -263,11 +263,13 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 {
 	struct altmode *partner = altmode->partner;
 	struct typec_altmode *adev;
+	struct typec_altmode *partner_adev;
 
 	if (!partner)
 		return;
 
-	adev = &partner->adev;
+	adev = &altmode->adev;
+	partner_adev = &partner->adev;
 
 	if (is_typec_plug(adev->dev.parent)) {
 		struct typec_plug *plug = to_typec_plug(adev->dev.parent);

@@ -276,7 +278,7 @@ static void typec_altmode_put_partner(struct altmode *altmode)
 	} else {
 		partner->partner = NULL;
 	}
-	put_device(&adev->dev);
+	put_device(&partner_adev->dev);
 }
 
 /**

@@ -497,7 +499,8 @@ static void typec_altmode_release(struct device *dev)
 {
 	struct altmode *alt = to_altmode(to_typec_altmode(dev));
 
-	typec_altmode_put_partner(alt);
+	if (!is_typec_port(dev->parent))
+		typec_altmode_put_partner(alt);
 
 	altmode_id_remove(alt->adev.dev.parent, alt->id);
 	kfree(alt);

base-commit: e7d3b9f28654dbfce7e09f8028210489adaf6a33

Signature · 1 line
2.43.0.472.g3155946c3a-goog
Signature · 1 line
heikki