[PATCH 5.10 60/80] usb: gadget: rndis: add spinlock for rndis response list

Greg Kroah-Hartman
2022-02-28T17:46:45Z

From: Daehwan Jung <dh10.jung@samsung.com>

commit aaaba1c86d04dac8e49bf508b492f81506257da3 upstream.

There's no lock for rndis response list. It could cause list corruption
if there're two different list_add at the same time like below.
It's better to add in rndis_add_response / rndis_free_response
/ rndis_get_next_response to prevent any race condition on response list.

[ 361.894299] [1: irq/191-dwc3:16979] list_add corruption.
next->prev should be prev (ffffff80651764d0),
but was ffffff883dc36f80. (next=ffffff80651764d0).

[ 361.904380] [1: irq/191-dwc3:16979] Call trace:
[ 361.904391] [1: irq/191-dwc3:16979] __list_add_valid+0x74/0x90
[ 361.904401] [1: irq/191-dwc3:16979] rndis_msg_parser+0x168/0x8c0
[ 361.904409] [1: irq/191-dwc3:16979] rndis_command_complete+0x24/0x84
[ 361.904417] [1: irq/191-dwc3:16979] usb_gadget_giveback_request+0x20/0xe4
[ 361.904426] [1: irq/191-dwc3:16979] dwc3_gadget_giveback+0x44/0x60
[ 361.904434] [1: irq/191-dwc3:16979] dwc3_ep0_complete_data+0x1e8/0x3a0
[ 361.904442] [1: irq/191-dwc3:16979] dwc3_ep0_interrupt+0x29c/0x3dc
[ 361.904450] [1: irq/191-dwc3:16979] dwc3_process_event_entry+0x78/0x6cc
[ 361.904457] [1: irq/191-dwc3:16979] dwc3_process_event_buf+0xa0/0x1ec
[ 361.904465] [1: irq/191-dwc3:16979] dwc3_thread_interrupt+0x34/0x5c

Fixes: f6281af9d62e ("usb: gadget: rndis: use list_for_each_entry_safe")
Cc: stable <stable@kernel.org>
Signed-off-by: Daehwan Jung <dh10.jung@samsung.com>
Link: https://lore.kernel.org/r/1645507768-77687-1-git-send-email-dh10.jung@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/gadget/function/rndis.c | 8 ++++++++
drivers/usb/gadget/function/rndis.h | 1 +
2 files changed, 9 insertions(+)

--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -922,6 +922,7 @@ struct rndis_params *rndis_register(void
params->resp_avail = resp_avail;
params->v = v;
INIT_LIST_HEAD(&params->resp_queue);
+ spin_lock_init(&params->resp_lock);
pr_debug("%s: configNr = %d\n", __func__, i);

return params;
@@ -1015,12 +1016,14 @@ void rndis_free_response(struct rndis_pa
{
rndis_resp_t *r, *n;

+ spin_lock(&params->resp_lock);
list_for_each_entry_safe(r, n, &params->resp_queue, list) {
if (r->buf == buf) {
list_del(&r->list);
kfree(r);
}
}
+ spin_unlock(&params->resp_lock);
}
EXPORT_SYMBOL_GPL(rndis_free_response);

@@ -1030,14 +1033,17 @@ u8 *rndis_get_next_response(struct rndis

if (!length) return NULL;

+ spin_lock(&params->resp_lock);
list_for_each_entry_safe(r, n, &params->resp_queue, list) {
if (!r->send) {
r->send = 1;
*length = r->length;
+ spin_unlock(&params->resp_lock);
return r->buf;
}
}

+ spin_unlock(&params->resp_lock);
return NULL;
}
EXPORT_SYMBOL_GPL(rndis_get_next_response);
@@ -1054,7 +1060,9 @@ static rndis_resp_t *rndis_add_response(
r->length = length;
r->send = 0;

+ spin_lock(&params->resp_lock);
list_add_tail(&r->list, &params->resp_queue);
+ spin_unlock(&params->resp_lock);
return r;
}

--- a/drivers/usb/gadget/function/rndis.h
+++ b/drivers/usb/gadget/function/rndis.h
@@ -174,6 +174,7 @@ typedef struct rndis_params {
void (*resp_avail)(void *v);
void *v;
struct list_head resp_queue;
+ spinlock_t resp_lock;
} rndis_params;

/* RNDIS Message parser and other useless functions */