linux-kernel - [PATCH 4.14 060/217] PCI: PM: Avoid forcing PCI

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

Message-Id: <20210920163926.662233474@linuxfoundation.org>
Date:   Mon, 20 Sep 2021 18:41:21 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Utkarsh H Patel <utkarsh.h.patel@...el.com>,
        Koba Ko <koba.ko@...onical.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 060/217] PCI: PM: Avoid forcing PCI_D0 for wakeup reasons inconsistently

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

[ Upstream commit da9f2150684ea684a7ddd6d7f0e38b2bdf43dcd8 ]

It is inconsistent to return PCI_D0 from pci_target_state() instead
of the original target state if 'wakeup' is true and the device
cannot signal PME from D0.

This only happens when the device cannot signal PME from the original
target state and any shallower power states (including D0) and that
case is effectively equivalent to the one in which PME singaling is
not supported at all.  Since the original target state is returned in
the latter case, make the function do that in the former one too.

Link: https://lore.kernel.org/linux-pm/3149540.aeNJFYEL58@kreacher/
Fixes: 666ff6f83e1d ("PCI/PM: Avoid using device_may_wakeup() for runtime PM")
Reported-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Reported-by: Utkarsh H Patel <utkarsh.h.patel@...el.com>
Reported-by: Koba Ko <koba.ko@...onical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Reviewed-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pci/pci.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index c847b5554db6..ac2c9d0c02fe 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2054,17 +2054,21 @@ static pci_power_t pci_target_state(struct pci_dev *dev, bool wakeup)
 	if (dev->current_state == PCI_D3cold)
 		target_state = PCI_D3cold;
 
-	if (wakeup) {
+	if (wakeup && dev->pme_support) {
+		pci_power_t state = target_state;
+
 		/*
 		 * Find the deepest state from which the device can generate
 		 * wake-up events, make it the target state and enable device
 		 * to generate PME#.
 		 */
-		if (dev->pme_support) {
-			while (target_state
-			      && !(dev->pme_support & (1 << target_state)))
-				target_state--;
-		}
+		while (state && !(dev->pme_support & (1 << state)))
+			state--;
+
+		if (state)
+			return state;
+		else if (dev->pme_support & 1)
+			return PCI_D0;
 	}
 
 	return target_state;
-- 
2.30.2