linux-kernel - [PATCH RFC v1 2/3] Fix hibernation restore hang in freeze

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]

Date:	Tue, 18 Feb 2014 17:52:08 -0800
From:	Sebastian Capella <sebastian.capella@...aro.org>
To:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	linaro-kernel@...ts.linaro.org,
	linux-arm-kernel@...ts.infradead.org
Cc:	Sebastian Capella <sebastian.capella@...aro.org>,
	Russ Dill <Russ.Dill@...com>,
	Ming Lei <ming.lei@...onical.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: [PATCH RFC v1 2/3] Fix hibernation restore hang in freeze_processes

During restore, pm_notifier chain are called with
PM_RESTORE_PREPARE.  The firmware_class driver handler
fw_pm_notify does not have a handler for this.  As a result,
it keeps a reader on the kmod.c umhelper_sem.  During
freeze_processes, the call to __usermodehelper_disable tries to
take a write lock on this semaphore and hangs waiting.

Signed-off-by: Sebastian Capella <sebastian.capella@...aro.org>
Cc: Russ Dill <Russ.Dill@...com>
Cc: Ming Lei <ming.lei@...onical.com>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/base/firmware_class.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index eb8fb94..e2b51f8 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -1541,6 +1541,7 @@ static int fw_pm_notify(struct notifier_block *notify_block,
 	switch (mode) {
 	case PM_HIBERNATION_PREPARE:
 	case PM_SUSPEND_PREPARE:
+	case PM_RESTORE_PREPARE:
 		kill_requests_without_uevent();
 		device_cache_fw_images();
 		break;
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/