linux-kernel - [PATCH] PM-runtime: fix denying of auto suspend in pm_suspend_timer

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: <20250515064125.1211561-1-quic_charante@quicinc.com>
Date: Thu, 15 May 2025 12:11:25 +0530
From: Charan Teja Kalla <quic_charante@...cinc.com>
To: <rafael@...nel.org>, <len.brown@...el.com>, <pavel@...nel.org>,
        <gregkh@...uxfoundation.org>, <dakr@...nel.org>
CC: <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Charan Teja
 Kalla" <quic_charante@...cinc.com>,
        Patrick Daly <quic_pdaly@...cinc.com>
Subject: [PATCH] PM-runtime: fix denying of auto suspend in pm_suspend_timer_fn

pm_runtime_put_autosuspend() schedules a hrtimer to expire at
"dev->power.timer_expires". If the hrtimer's callback -
pm_suspend_timer_fn - observes that the current time equals
"dev->power.timer_expires", it unexpectedly bails out instead of
proceeding with runtime suspend.

pm_suspend_timer_fn():
if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
	dev->power.timer_expires = 0;
	rpm_suspend(..)
}

Additionally, as ->timer_expires is not cleared, all the future auto
suspend requests will not schedule hrtimer to perform auto suspend.

rpm_suspend():
if ((rpmflags & RPM_AUTO) &&...) {
     if (!(dev->power.timer_expires && ...) { <-- this will fail.
	hrtimer_start_range_ns(&dev->power.suspend_timer,...);
  }
}

Fix this by aswell checking if current time reaches the set expiration.

Co-developed-by: Patrick Daly <quic_pdaly@...cinc.com>
Signed-off-by: Patrick Daly <quic_pdaly@...cinc.com>
Signed-off-by: Charan Teja Kalla <quic_charante@...cinc.com>
---
 drivers/base/power/runtime.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 205a4f8828b0..c55a7c70bc1a 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1011,7 +1011,7 @@ static enum hrtimer_restart  pm_suspend_timer_fn(struct hrtimer *timer)
 	 * If 'expires' is after the current time, we've been called
 	 * too early.
 	 */
-	if (expires > 0 && expires < ktime_get_mono_fast_ns()) {
+	if (expires > 0 && expires <= ktime_get_mono_fast_ns()) {
 		dev->power.timer_expires = 0;
 		rpm_suspend(dev, dev->power.timer_autosuspends ?
 		    (RPM_ASYNC | RPM_AUTO) : RPM_ASYNC);
-- 
2.34.1