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-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20230807171148.210181-3-robdclark@gmail.com>
Date:   Mon,  7 Aug 2023 10:11:36 -0700
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...omium.org>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        linux-pm@...r.kernel.org (open list:DEVICE FREQUENCY (DEVFREQ)),
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v4 2/9] PM / devfreq: Teach lockdep about locking order

From: Rob Clark <robdclark@...omium.org>

This will make it easier to catch places doing allocations that can
trigger reclaim under devfreq->lock.

Because devfreq->lock is held over various devfreq_dev_profile
callbacks, there might be some fallout if those callbacks do allocations
that can trigger reclaim, but I've looked through the various callback
implementations and don't see anything obvious.  If it does trigger any
lockdep splats, those should be fixed.

Signed-off-by: Rob Clark <robdclark@...omium.org>
---
 drivers/devfreq/devfreq.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index e5558ec68ce8..81add6064406 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -817,6 +817,12 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	}
 
 	mutex_init(&devfreq->lock);
+
+	/* Teach lockdep about lock ordering wrt. shrinker: */
+	fs_reclaim_acquire(GFP_KERNEL);
+	might_lock(&devfreq->lock);
+	fs_reclaim_release(GFP_KERNEL);
+
 	devfreq->dev.parent = dev;
 	devfreq->dev.class = devfreq_class;
 	devfreq->dev.release = devfreq_dev_release;
-- 
2.41.0

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ