On 10/19/2023 3:42 AM, Johan Hovold wrote:
The ath11k active pdevs are protected by RCU but the temperature event
handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a
read-side critical section as reported by RCU lockdep:
How do I enable this? Just enable CONFIG_PROVE_RCU?
Of course I'd also need to exercise the code path...
=============================
WARNING: suspicious RCU usage
6.6.0-rc6 #7 Not tainted
-----------------------------
drivers/net/wireless/ath/ath11k/mac.c:638 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
no locks held by swapper/0/0.
...
Call trace:
...
lockdep_rcu_suspicious+0x16c/0x22c
ath11k_mac_get_ar_by_pdev_id+0x194/0x1b0 [ath11k]
ath11k_wmi_tlv_op_rx+0xa84/0x2c1c [ath11k]
ath11k_htc_rx_completion_handler+0x388/0x510 [ath11k]
Mark the code in question as an RCU read-side critical section to avoid
any potential use-after-free issues.
Fixes: a41d10348b01 ("ath11k: add thermal sensor device support")
Cc: stable@xxxxxxxxxxxxxxx # 5.7
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
---
drivers/net/wireless/ath/ath11k/wmi.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c
index 23ad6825e5be..980ff588325d 100644
--- a/drivers/net/wireless/ath/ath11k/wmi.c
+++ b/drivers/net/wireless/ath/ath11k/wmi.c
@@ -8383,6 +8383,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab,
ath11k_dbg(ab, ATH11K_DBG_WMI, "event pdev temperature ev temp %d pdev_id %d\n",
ev->temp, ev->pdev_id);
+ rcu_read_lock();
+
ar = ath11k_mac_get_ar_by_pdev_id(ab, ev->pdev_id);
if (!ar) {
ath11k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev->pdev_id);
aren't you missing an unlock() in this error path?
perhaps have a goto cleanup that does both the unlock() and the kfree()?
@@ -8392,6 +8394,8 @@ ath11k_wmi_pdev_temperature_event(struct ath11k_base *ab,
ath11k_thermal_event_temperature(ar, ev->temp);
+ rcu_read_unlock();
+
kfree(tb);
}
