linux-kernel - [PATCH v1] opp: Release current OPP properly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 12 Aug 2021 13:13:53 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Viresh Kumar <vireshk@...nel.org>, Stephen Boyd <sboyd@...nel.org>,
        Nishanth Menon <nm@...com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH v1] opp: Release current OPP properly

The current_opp is released only when whole OPP table is released,
otherwise it's only marked as removed by dev_pm_opp_remove_table().
Functions like dev_pm_opp_put_clkname() and dev_pm_opp_put_supported_hw()
are checking whether OPP table is empty and it's not if current_opp is
set since it holds the refcount of OPP, this produces a noisy warning
from these functions about busy OPP table. Release current_opp when
OPP table is removed to fix it.

Cc: stable@...r.kernel.org
Fixes: 81c4d8a3c414 ("opp: Keep track of currently programmed OPP")
Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/opp/core.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index b335c077f215..73da968b5c86 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -1378,9 +1378,6 @@ static void _opp_table_kref_release(struct kref *kref)
 	list_del(&opp_table->node);
 	mutex_unlock(&opp_table_lock);
 
-	if (opp_table->current_opp)
-		dev_pm_opp_put(opp_table->current_opp);
-
 	_of_clear_opp_table(opp_table);
 
 	/* Release clk */
@@ -2901,6 +2898,12 @@ void dev_pm_opp_remove_table(struct device *dev)
 	if (_opp_remove_all_static(opp_table))
 		dev_pm_opp_put_opp_table(opp_table);
 
+	/* Drop reference taken by _find_current_opp() */
+	if (opp_table->current_opp) {
+		dev_pm_opp_put(opp_table->current_opp);
+		opp_table->current_opp = NULL;
+	}
+
 	/* Drop reference taken by _find_opp_table() */
 	dev_pm_opp_put_opp_table(opp_table);
 }
-- 
2.32.0