PM: hibernate: Add error handling for syscore_suspend()

In hibernation_platform_enter(), the code did not check the
return value of syscore_suspend(), potentially leading to a
situation where syscore_resume() would be called even if
syscore_suspend() failed. This could cause unpredictable
behavior or system instability.

Modify the code sequence in question to properly handle errors returned
by syscore_suspend(). If an error occurs in the suspend path, the code
now jumps to label 'Enable_irqs' skipping the syscore_resume() call and
only enabling interrupts after setting the system state to SYSTEM_RUNNING.

Fixes: 40dc166 ("PM / Core: Introduce struct syscore_ops for core subsystems PM")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Link: https://patch.msgid.link/20250119143205.2103-1-vulab@iscas.ac.cn
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/hibernate.c

@@ -608,7 +608,11 @@ int hibernation_platform_enter(void)
 
 	local_irq_disable();
 	system_state = SYSTEM_SUSPEND;
-	syscore_suspend();
+
+	error = syscore_suspend();
+	if (error)
+		goto Enable_irqs;
+
 	if (pm_wakeup_pending()) {
 		error = -EAGAIN;
 		goto Power_up;
@@ -620,6 +624,7 @@ int hibernation_platform_enter(void)
 
  Power_up:
 	syscore_resume();
+ Enable_irqs:
 	system_state = SYSTEM_RUNNING;
 	local_irq_enable();