ath10k: fix ath10k_debug_start() locking

ath10k_debug_start() was not called with conf_mutex, fix that. Also there was a
deadlock in ath10k_debug_stop(), rename it to ath10k_debug_destroy() and call
it only when the device is destroyed.

Reported-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/net/wireless/ath/ath10k/debug.c b/drivers/net/wireless/ath/ath10k/debug.c
index 59615c7f217e..760ff2289e3c 100644
--- a/drivers/net/wireless/ath/ath10k/debug.c
+++ b/drivers/net/wireless/ath/ath10k/debug.c
@@ -618,6 +618,8 @@ int ath10k_debug_start(struct ath10k *ar)
 {
         int ret;
 
+        lockdep_assert_held(&ar->conf_mutex);
+
         ret = ath10k_debug_htt_stats_req(ar);
         if (ret)
                 /* continue normally anyway, this isn't serious */
@@ -628,7 +630,13 @@ int ath10k_debug_start(struct ath10k *ar)
 
 void ath10k_debug_stop(struct ath10k *ar)
 {
-        cancel_delayed_work_sync(&ar->debug.htt_stats_dwork);
+        lockdep_assert_held(&ar->conf_mutex);
+
+        /* Must not use _sync to avoid deadlock, we do that in
+         * ath10k_debug_destroy(). The check for htt_stats_mask is to avoid
+         * warning from del_timer(). */
+        if (ar->debug.htt_stats_mask != 0)
+                cancel_delayed_work(&ar->debug.htt_stats_dwork);
 }
 
 int ath10k_debug_create(struct ath10k *ar)
@@ -662,6 +670,11 @@ int ath10k_debug_create(struct ath10k *ar)
         return 0;
 }
 
+void ath10k_debug_destroy(struct ath10k *ar)
+{
+        cancel_delayed_work_sync(&ar->debug.htt_stats_dwork);
+}
+
 #endif /* CONFIG_ATH10K_DEBUGFS */
 
 #ifdef CONFIG_ATH10K_DEBUG