linux-kernel - [PATCH] PM: runtime: Return -EINPROGRESS from rpm_resume() in the RPM

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: <12079576.O9o76ZdvQC@kreacher>
Date:   Thu, 22 Sep 2022 20:04:40 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     Douglas Anderson <dianders@...omium.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH] PM: runtime: Return -EINPROGRESS from rpm_resume() in the RPM_NOWAIT case

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

The prospective callers of rpm_resume() passing RPM_NOWAIT to it may
be confused when it returns 0 without actually resuming the device
which may happen if the device is suspending at the given time and it
will only resume when the suspend in progress has completed.  To avoid
that confusion, return -EINPROGRESS from rpm_resume() in that case.

Since none of the current callers passing RPM_NOWAIT to rpm_resume()
check its return value, this change has no functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/base/power/runtime.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/base/power/runtime.c
===================================================================
--- linux-pm.orig/drivers/base/power/runtime.c
+++ linux-pm/drivers/base/power/runtime.c
@@ -792,10 +792,13 @@ static int rpm_resume(struct device *dev
 		DEFINE_WAIT(wait);
 
 		if (rpmflags & (RPM_ASYNC | RPM_NOWAIT)) {
-			if (dev->power.runtime_status == RPM_SUSPENDING)
+			if (dev->power.runtime_status == RPM_SUSPENDING) {
 				dev->power.deferred_resume = true;
-			else
+				if (rpmflags & RPM_NOWAIT)
+					retval = -EINPROGRESS;
+			} else {
 				retval = -EINPROGRESS;
+			}
 			goto out;
 		}