Commit d7d41682 authored Feb 25, 2020 by Madhuparna Bhowmik Committed by Marcel Holtmann Feb 28, 2020

Bluetooth: Fix Suspicious RCU usage warnings



The following functions in hci_core are always called with
hdev->lock held. No need to use list_for_each_entry_rcu(), therefore
change the usage of list_for_each_entry_rcu() in these functions
to list_for_each_entry().

hci_link_keys_clear()
hci_smp_ltks_clear()
hci_smp_irks_clear()
hci_blocked_keys_clear()

Warning encountered with CONFIG_PROVE_RCU_LIST:

[   72.213184] =============================
[   72.213188] WARNING: suspicious RCU usage
[   72.213192] 5.6.0-rc1+ #5 Not tainted
[   72.213195] -----------------------------
[   72.213198] net/bluetooth/hci_core.c:2288 RCU-list traversed in non-reader section!!

[   72.213676] =============================
[   72.213679] WARNING: suspicious RCU usage
[   72.213683] 5.6.0-rc1+ #5 Not tainted
[   72.213685] -----------------------------
[   72.213689] net/bluetooth/hci_core.c:2298 RCU-list traversed in non-reader section!!

[   72.214195] =============================
[   72.214198] WARNING: suspicious RCU usage
[   72.214201] 5.6.0-rc1+ #5 Not tainted
[   72.214204] -----------------------------
[   72.214208] net/bluetooth/hci_core.c:2308 RCU-list traversed in non-reader section!!

[  333.456972] =============================
[  333.456979] WARNING: suspicious RCU usage
[  333.457001] 5.6.0-rc1+ #5 Not tainted
[  333.457007] -----------------------------
[  333.457014] net/bluetooth/hci_core.c:2318 RCU-list traversed in non-reader section!!

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

parent a7e45454

net/bluetooth/hci_core.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -2285,7 +2285,7 @@ void hci_link_keys_clear(struct hci_dev *hdev)
		{
		struct link_key *key;

		list_for_each_entry_rcu(key, &hdev->link_keys, list) {
		list_for_each_entry(key, &hdev->link_keys, list) {
		list_del_rcu(&key->list);
		kfree_rcu(key, rcu);
		}
		@@ -2295,7 +2295,7 @@ void hci_smp_ltks_clear(struct hci_dev *hdev)
		{
		struct smp_ltk *k;

		list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
		list_for_each_entry(k, &hdev->long_term_keys, list) {
		list_del_rcu(&k->list);
		kfree_rcu(k, rcu);
		}
		@@ -2305,7 +2305,7 @@ void hci_smp_irks_clear(struct hci_dev *hdev)
		{
		struct smp_irk *k;

		list_for_each_entry_rcu(k, &hdev->identity_resolving_keys, list) {
		list_for_each_entry(k, &hdev->identity_resolving_keys, list) {
		list_del_rcu(&k->list);
		kfree_rcu(k, rcu);
		}
		@@ -2315,7 +2315,7 @@ void hci_blocked_keys_clear(struct hci_dev *hdev)
		{
		struct blocked_key *b;

		list_for_each_entry_rcu(b, &hdev->blocked_keys, list) {
		list_for_each_entry(b, &hdev->blocked_keys, list) {
		list_del_rcu(&b->list);
		kfree_rcu(b, rcu);
		}

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