[PATCH ath-next] wifi: ath12k: fix OF node refcount imbalance in WSI graph traversal
Aaradhana Sahu
aaradhana.sahu at oss.qualcomm.com
Fri Apr 10 00:13:00 PDT 2026
ath12k_core_get_wsi_info() traverses the WSI (Wired Serial Interface)
device graph starting from dev->of_node. The current code uses
dev->of_node directly as the local traversal pointer and calls
of_node_put() on error.
Since the driver does not own a reference to dev->of_node, dropping it
during traversal results in the following OF refcount underflow:
OF: ERROR: of_node_release() detected bad of_node_put() on /soc at 0/wifi at c000000
CPU: 1 UID: 0 PID: 210 Comm: insmod Not tainted 6.19.0-rc4-next-20260109-00023-g797dd36dc178 #26 PREEMPT
Hardware name: Qualcomm Technologies, Inc. IPQ5332 MI01.2 (DT)
Call trace:
show_stack+0x18/0x24 (C)
dump_stack_lvl+0x60/0x80
dump_stack+0x18/0x24
of_node_release+0x164/0x1a0
kobject_put+0xb4/0x278
of_node_put+0x18/0x28
ath12k_core_init+0x29c/0x5d4 [ath12k]
ath12k_ahb_probe+0x950/0xc14 [ath12k]
platform_probe+0x5c/0xa4
really_probe+0xc0/0x3ec
__driver_probe_device+0x80/0x170
driver_probe_device+0x3c/0x120
__driver_attach+0xc4/0x218
OF: ERROR: next of_node_put() on this node will result in a kobject warning 'refcount_t: underflow; use-after-free.'
Fix this by explicitly acquiring a reference to the starting node
using of_node_get() and attaching automatic cleanup via
__free(device_node).
Each discovered WSI node is stored in ag->wsi_node[] with its own
of_node_get() reference. These references are later released in
ath12k_core_free_wsi_info() during driver teardown.
Also remove unnecessary memset() of wsi_node array since cleanup now
explicitly sets pointers to NULL.
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.6-01243-QCAHKSWPL_SILICONZ-1
Tested-on: IPQ5332 hw1.0 AHB WLAN.WBE.1.6-01275-QCAHKSWPL_SILICONZ-1
Fixes: 908c10c860e0 ("wifi: ath12k: parse multiple device information from Device Tree")
Signed-off-by: Aaradhana Sahu <aaradhana.sahu at oss.qualcomm.com>
---
drivers/net/wireless/ath/ath12k/core.c | 77 ++++++++++++++++----------
1 file changed, 48 insertions(+), 29 deletions(-)
diff --git a/drivers/net/wireless/ath/ath12k/core.c b/drivers/net/wireless/ath/ath12k/core.c
index 2519e2400d58..980a12fb2c6e 100644
--- a/drivers/net/wireless/ath/ath12k/core.c
+++ b/drivers/net/wireless/ath/ath12k/core.c
@@ -1838,10 +1838,22 @@ static struct ath12k_hw_group *ath12k_core_hw_group_alloc(struct ath12k_base *ab
return ag;
}
+static void ath12k_core_free_wsi_info(struct ath12k_hw_group *ag)
+{
+ int i;
+
+ for (i = 0; i < ag->num_devices; i++) {
+ of_node_put(ag->wsi_node[i]);
+ ag->wsi_node[i] = NULL;
+ }
+ ag->num_devices = 0;
+}
+
static void ath12k_core_hw_group_free(struct ath12k_hw_group *ag)
{
mutex_lock(&ath12k_hw_group_mutex);
+ ath12k_core_free_wsi_info(ag);
list_del(&ag->list);
kfree(ag);
@@ -1867,52 +1879,59 @@ static struct ath12k_hw_group *ath12k_core_hw_group_find_by_dt(struct ath12k_bas
static int ath12k_core_get_wsi_info(struct ath12k_hw_group *ag,
struct ath12k_base *ab)
{
- struct device_node *wsi_dev = ab->dev->of_node, *next_wsi_dev;
- struct device_node *tx_endpoint, *next_rx_endpoint;
- int device_count = 0;
-
- next_wsi_dev = wsi_dev;
+ struct device_node *next_wsi_dev;
+ int device_count = 0, ret = 0;
+ struct device_node *wsi_dev;
- if (!next_wsi_dev)
+ wsi_dev = of_node_get(ab->dev->of_node);
+ if (!wsi_dev)
return -ENODEV;
do {
- ag->wsi_node[device_count] = next_wsi_dev;
+ if (device_count >= ATH12K_MAX_DEVICES) {
+ ath12k_warn(ab, "device count in DT %d is more than limit %d\n",
+ device_count, ATH12K_MAX_DEVICES);
+ ret = -EINVAL;
+ break;
+ }
+
+ ag->wsi_node[device_count++] = of_node_get(wsi_dev);
- tx_endpoint = of_graph_get_endpoint_by_regs(next_wsi_dev, 0, -1);
+ struct device_node *tx_endpoint __free(device_node) =
+ of_graph_get_endpoint_by_regs(wsi_dev, 0, -1);
if (!tx_endpoint) {
- of_node_put(next_wsi_dev);
- return -ENODEV;
+ ret = -ENODEV;
+ break;
}
- next_rx_endpoint = of_graph_get_remote_endpoint(tx_endpoint);
+ struct device_node *next_rx_endpoint __free(device_node) =
+ of_graph_get_remote_endpoint(tx_endpoint);
if (!next_rx_endpoint) {
- of_node_put(next_wsi_dev);
- of_node_put(tx_endpoint);
- return -ENODEV;
+ ret = -ENODEV;
+ break;
}
- of_node_put(tx_endpoint);
- of_node_put(next_wsi_dev);
-
next_wsi_dev = of_graph_get_port_parent(next_rx_endpoint);
if (!next_wsi_dev) {
- of_node_put(next_rx_endpoint);
- return -ENODEV;
+ ret = -ENODEV;
+ break;
}
- of_node_put(next_rx_endpoint);
+ of_node_put(wsi_dev);
+ wsi_dev = next_wsi_dev;
+ } while (ab->dev->of_node != wsi_dev);
- device_count++;
- if (device_count > ATH12K_MAX_DEVICES) {
- ath12k_warn(ab, "device count in DT %d is more than limit %d\n",
- device_count, ATH12K_MAX_DEVICES);
- of_node_put(next_wsi_dev);
- return -EINVAL;
+ if (ret) {
+ while (--device_count >= 0) {
+ of_node_put(ag->wsi_node[device_count]);
+ ag->wsi_node[device_count] = NULL;
}
- } while (wsi_dev != next_wsi_dev);
- of_node_put(next_wsi_dev);
+ of_node_put(wsi_dev);
+ return ret;
+ }
+
+ of_node_put(wsi_dev);
ag->num_devices = device_count;
return 0;
@@ -1983,9 +2002,9 @@ static struct ath12k_hw_group *ath12k_core_hw_group_assign(struct ath12k_base *a
ath12k_core_get_wsi_index(ag, ab)) {
ath12k_dbg(ab, ATH12K_DBG_BOOT,
"unable to get wsi info from dt, grouping single device");
+ ath12k_core_free_wsi_info(ag);
ag->id = ATH12K_INVALID_GROUP_ID;
ag->num_devices = 1;
- memset(ag->wsi_node, 0, sizeof(ag->wsi_node));
wsi->index = 0;
}
base-commit: ae530e0b135102c5fc08e64c39e7a18564a52b3e
--
2.34.1
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