As part of the registration of a new 'struct usb_phy' with the USB PHY core via either usb_add_phy(struct usb_phy *x, ...) or usb_add_phy_dev(struct usb_phy *x) these functions call list_add_tail(&x->head, phy_list) in order for the new instance x to be stored in phy_list, a static list kept internally by the core.

After 7d21114dc6a2 ("usb: phy: Introduce one extcon device into usb phy") when executing either of the registration functions above it is possible that usb_add_extcon() fails, leading to either function returning before the call to list_add_tail(), leaving x->head uninitialized.

Then, when a driver tries to undo the failed registration by calling usb_remove_phy(struct usb_phy *x) there will be an unconditional call to list_del(&x->head) acting on an uninitialized variable, and thus a possible NULL pointer dereference.

Fix this by initializing x->head before usb_add_extcon() has a chance to fail. Note that this was not needed before 7d21114dc6a2 since list_add_phy() was executed unconditionally and it guaranteed that x->head was initialized.

Fixes: 7d21114dc6a2 ("usb: phy: Introduce one extcon device into usb phy") Cc: stable@vger.kernel.org Signed-off-by: Diogo Ivo diogo.ivo@tecnico.ulisboa.pt --- Changes in v2: - Adjust Fixes: sha1 to 12 digits - Reword commit message to clarify the need to introduce INIT_LIST_HEAD() - Link to v1: https://lore.kernel.org/r/20251113-diogo-smaug_typec-v1-1-f1aa3b48620d@tecni... --- drivers/usb/phy/phy.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/phy/phy.c b/drivers/usb/phy/phy.c index e1435bc59662..5a9b9353f343 100644 --- a/drivers/usb/phy/phy.c +++ b/drivers/usb/phy/phy.c @@ -646,6 +646,8 @@ int usb_add_phy(struct usb_phy *x, enum usb_phy_type type) return -EINVAL; }

+ INIT_LIST_HEAD(&x->head); + usb_charger_init(x); ret = usb_add_extcon(x); if (ret) @@ -696,6 +698,8 @@ int usb_add_phy_dev(struct usb_phy *x) return -EINVAL; }

+ INIT_LIST_HEAD(&x->head); + usb_charger_init(x); ret = usb_add_extcon(x); if (ret)

--- base-commit: b612b9a01026a268af6a191180e846ad121d1eab change-id: 20251113-diogo-smaug_typec-56b2059b892b

Best regards,