Hi Ondřej,
On 5/7/24 09:19, Ondřej Jirman wrote:
On Wed, Apr 24, 2024 at 03:32:16PM GMT, Amit Sunil Dhamne wrote:
Check and unregister existing source caps in tcpm_register_source_caps
function before registering new ones. This change fixes following
warning when port partner resends source caps after negotiating PD contract
for the purpose of re-negotiation.
[ 343.135030][ T151] sysfs: cannot create duplicate filename '/devices/virtual/usb_power_delivery/pd1/source-capabilities'
[ 343.135071][ T151] Call trace:
[ 343.135076][ T151] dump_backtrace+0xe8/0x108
[ 343.135099][ T151] show_stack+0x18/0x24
[ 343.135106][ T151] dump_stack_lvl+0x50/0x6c
[ 343.135119][ T151] dump_stack+0x18/0x24
[ 343.135126][ T151] sysfs_create_dir_ns+0xe0/0x140
[ 343.135137][ T151] kobject_add_internal+0x228/0x424
[ 343.135146][ T151] kobject_add+0x94/0x10c
[ 343.135152][ T151] device_add+0x1b0/0x4c0
[ 343.135187][ T151] device_register+0x20/0x34
[ 343.135195][ T151] usb_power_delivery_register_capabilities+0x90/0x20c
[ 343.135209][ T151] tcpm_pd_rx_handler+0x9f0/0x15b8
[ 343.135216][ T151] kthread_worker_fn+0x11c/0x260
[ 343.135227][ T151] kthread+0x114/0x1bc
[ 343.135235][ T151] ret_from_fork+0x10/0x20
[ 343.135265][ T151] kobject: kobject_add_internal failed for source-capabilities with -EEXIST, don't try to register things with the same name in the same directory.
Fixes: 8203d26905ee ("usb: typec: tcpm: Register USB Power Delivery Capabilities")
Cc: linux-usb@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Amit Sunil Dhamne <amitsd@xxxxxxxxxx>
---
drivers/usb/typec/tcpm/tcpm.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index ab6ed6111ed0..d8eb89f4f0c3 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -2996,7 +2996,7 @@ static int tcpm_register_source_caps(struct tcpm_port *port)
{
struct usb_power_delivery_desc desc = { port->negotiated_rev };
struct usb_power_delivery_capabilities_desc caps = { };
- struct usb_power_delivery_capabilities *cap;
+ struct usb_power_delivery_capabilities *cap = port->partner_source_caps;
if (!port->partner_pd)
port->partner_pd = usb_power_delivery_register(NULL, &desc);
@@ -3006,6 +3006,9 @@ static int tcpm_register_source_caps(struct tcpm_port *port)
memcpy(caps.pdo, port->source_caps, sizeof(u32) * port->nr_source_caps);
caps.role = TYPEC_SOURCE;
+ if (cap)
+ usb_power_delivery_unregister_capabilities(cap);
This certainly looks like it's asking for use after free on port->partner_source_caps
later on, since you're not clearing the pointer for the data that you just freed.
+
cap = usb_power_delivery_register_capabilities(port->partner_pd, &caps);
if (IS_ERR(cap))
return PTR_ERR(cap);
This can easily fail if caps contain invalid PDOs, resulting in keeping pointer
to freed memory in port->partner_source_caps.
Makes sense. I will send a fix for this. Thanks for the review.
Thanks,
Amit
Kind regards,
o.
base-commit: 0d31ea587709216d88183fe4ca0c8aba5e0205b8
--
2.44.0.769.g3c40516874-goog
