Re: [PATCH 7/7] [RFC] APM emulation driver for class batteries

Hi!

+static void (*old_apm_get_power_status)(struct apm_power_info*);
+
+static int __init apm_battery_init(void)
+{
+ printk(KERN_INFO "APM Battery Driver\n");
+
+ old_apm_get_power_status = apm_get_power_status;
+ apm_get_power_status = apm_battery_apm_get_power_status;
+ return 0;
+}
+
+static void __exit apm_battery_exit(void)
+{
+ apm_get_power_status = old_apm_get_power_status;
+ return;
+}

Utterly unsafe. What happens if some other module gets loaded which
does this, and then this module is unloaded followed by the other
module. Result: Oops.

Right. And loading two modules which changing apm_get_power_status
is a race already. Thus, APM interface needs a mutex.

Or pda_power should be marked "bool" in Kconfig, as it is done
in arch/arm/common/sharpsl_pm.c. Sharpsl_pm is safe only because it
can't be a module.

Just mark it bool, when you fix it with mutex, you can go back to
tristate.
Pavel

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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