media: cec: core: avoid recursive cec_claim_log_addrs

Keep track if cec_claim_log_addrs() is running, and return -EBUSY
if it is when calling CEC_ADAP_S_LOG_ADDRS.

This prevents a case where cec_claim_log_addrs() could be called
while it was still in progress.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Reported-by: Yang, Chenyuan <cy54@illinois.edu>
Closes: https://lore.kernel.org/linux-media/PH7PR11MB57688E64ADE4FE82E658D86DA09EA@PH7PR11MB5768.namprd11.prod.outlook.com/
Fixes: ca68438 ("[media] cec: add HDMI CEC framework (api)")
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Author: Hans Verkuil

drivers/media/cec/core/cec-adap.c

@@ -1574,9 +1574,12 @@ static int cec_config_thread_func(void *arg)
  */
 static void cec_claim_log_addrs(struct cec_adapter *adap, bool block)
 {
-	if (WARN_ON(adap->is_configuring || adap->is_configured))
+	if (WARN_ON(adap->is_claiming_log_addrs ||
+		    adap->is_configuring || adap->is_configured))
 		return;
 
+	adap->is_claiming_log_addrs = true;
+
 	init_completion(&adap->config_completion);
 
 	/* Ready to kick off the thread */
@@ -1591,6 +1594,7 @@ static void cec_claim_log_addrs(struct cec_adapter *adap, bool block)
 		wait_for_completion(&adap->config_completion);
 		mutex_lock(&adap->lock);
 	}
+	adap->is_claiming_log_addrs = false;
 }
 
 /*

drivers/media/cec/core/cec-api.c

@@ -178,7 +178,7 @@ static long cec_adap_s_log_addrs(struct cec_adapter *adap, struct cec_fh *fh,
 			   CEC_LOG_ADDRS_FL_ALLOW_RC_PASSTHRU |
 			   CEC_LOG_ADDRS_FL_CDC_ONLY;
 	mutex_lock(&adap->lock);
-	if (!adap->is_configuring &&
+	if (!adap->is_claiming_log_addrs && !adap->is_configuring &&
 	    (!log_addrs.num_log_addrs || !adap->is_configured) &&
 	    !cec_is_busy(adap, fh)) {
 		err = __cec_s_log_addrs(adap, &log_addrs, block);

include/media/cec.h

@@ -258,6 +258,7 @@ struct cec_adapter {
 	u16 phys_addr;
 	bool needs_hpd;
 	bool is_enabled;
+	bool is_claiming_log_addrs;
 	bool is_configuring;
 	bool must_reconfigure;
 	bool is_configured;