linux-kernel - [RFC PATCH] PM: wakeup: set device_set_wakeup

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20250129112056.3051949-1-d-gole@ti.com>
Date: Wed, 29 Jan 2025 16:50:56 +0530
From: Dhruva Gole <d-gole@...com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Markus
 Schneider-Pargmann <msp@...libre.com>,
        Kevin Hilman <khilman@...libre.com>, Dhruva Gole <d-gole@...com>,
        Joe Hattori <joe@...is.s.u-tokyo.ac.jp>
Subject: [RFC PATCH] PM: wakeup: set device_set_wakeup_capable to false in case of error

In device_init_wakeup enable, we first set device_set_wakeup_capable to
true. However in case the device_wakeup_enable fails for whatever reason,
there was no error handling being done.
Consequenty, there was no cleanup being done to device_set_wakeup_capable.

If a certain API is enabling something, it should take care of disabling it
in error scenarios. In this case device_init_wakeup should on it's own
check for errors and clean up accordingly.

Cc: Joe Hattori <joe@...is.s.u-tokyo.ac.jp>
Signed-off-by: Dhruva Gole <d-gole@...com>
---

This patch was briefly proposed in a related thread [1], where this discussion
was taking place.
That probably got missed due to some confusion around the device_init_wakeup
return value.

There is infact error returning being done in drivers/base/power/wakeup.c, and
ideally we should be using that info as done in this patch.

If this patch get accepted, it might even bring forth few hidden bugs
due to missing error handling, and it will also change the patch for
devm_device_init_wakeup() helper slightly[2].

[1] https://lore.kernel.org/linux-pm/20241218064335.c72gmw56ogtp36a2@lcpd911/
[2] https://lore.kernel.org/linux-pm/20241214021652.3432500-1-joe@pf.is.s.u-tokyo.ac.jp/

---
 include/linux/pm_wakeup.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/include/linux/pm_wakeup.h b/include/linux/pm_wakeup.h
index d501c09c60cd..ed62a7055a54 100644
--- a/include/linux/pm_wakeup.h
+++ b/include/linux/pm_wakeup.h
@@ -231,9 +231,13 @@ static inline void pm_wakeup_hard_event(struct device *dev)
  */
 static inline int device_init_wakeup(struct device *dev, bool enable)
 {
+	int err;
 	if (enable) {
 		device_set_wakeup_capable(dev, true);
-		return device_wakeup_enable(dev);
+		err = device_wakeup_enable(dev);
+		if (err)
+			device_set_wakeup_capable(dev, false);
+		return err;
 	}
 	device_wakeup_disable(dev);
 	device_set_wakeup_capable(dev, false);
-- 
2.34.1