PM: hibernate: Restrict GFP mask in power_down()

JIRA: https://issues.redhat.com/browse/RHEL-109250

commit 6f4c6f9
Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date:   Fri Sep 26 18:40:25 2025 +0200

Commit 12ffc3b ("PM: Restrict swap use to later in the
suspend sequence") caused hibernation_platform_enter() to call
pm_restore_gfp_mask() via dpm_resume_end(), so when power_down()
returns after aborting hibernation_platform_enter(), it needs
to match the pm_restore_gfp_mask() call in hibernate() that will
occur subsequently.

Address this by adding a pm_restrict_gfp_mask() call to the relevant
error path in power_down().

Fixes: 12ffc3b ("PM: Restrict swap use to later in the suspend sequence")
Cc: 6.16+ <stable@vger.kernel.org> # 6.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Mark Langsdorf <mlangsdo@redhat.com>

Author: mlangsdorf

kernel/power/hibernate.c

@@ -685,6 +685,8 @@ static void power_down(void)
 	case HIBERNATION_PLATFORM:
 		error = hibernation_platform_enter();
 		if (error == -EAGAIN || error == -EBUSY) {
+			/* Match pm_restore_gfp_mask() in hibernate(). */
+			pm_restrict_gfp_mask();
 			swsusp_unmark();
 			events_check_enabled = false;
 			pr_info("Wakeup event detected during hibernation, rolling back.\n");