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Commit a144c6a6 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

PM: Print a warning if firmware is requested when tasks are frozen 



Some drivers erroneously use request_firmware() from their ->resume()
(or ->thaw(), or ->restore()) callbacks, which is not going to work
unless the firmware has been built in.  This causes system resume to
stall until the firmware-loading timeout expires, which makes users
think that the resume has failed and reboot their machines
unnecessarily.  For this reason, make _request_firmware() print a
warning and return immediately with error code if it has been called
when tasks are frozen and it's impossible to start any new usermode
helpers.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: default avatarValdis Kletnieks <valdis.kletnieks@vt.edu>
parent e1866b33

drivers/base/firmware_class.c

+5 −0
Original line number Diff line number Diff line
@@ -521,6 +521,11 @@ static int _request_firmware(const struct firmware **firmware_p, 
	if (!firmware_p)

		return -EINVAL;



	if (WARN_ON(usermodehelper_is_disabled())) {

		dev_err(device, "firmware: %s will not be loaded\n", name);

		return -EBUSY;

	}



	*firmware_p = firmware = kzalloc(sizeof(*firmware), GFP_KERNEL);

	if (!firmware) {

		dev_err(device, "%s: kmalloc(struct firmware) failed\n",

include/linux/kmod.h

+5 −0
Original line number Diff line number Diff line
@@ -111,7 +111,12 @@ call_usermodehelper(char *path, char **argv, char **envp, enum umh_wait wait) 


extern void usermodehelper_init(void);



#ifdef CONFIG_PM_SLEEP

extern int usermodehelper_disable(void);

extern void usermodehelper_enable(void);

extern bool usermodehelper_is_disabled(void);

#else

static inline bool usermodehelper_is_disabled(void) { return false; }

#endif



#endif /* __LINUX_KMOD_H__ */

kernel/kmod.c

+9 −0
Original line number Diff line number Diff line
@@ -301,6 +301,15 @@ void usermodehelper_enable(void) 
	usermodehelper_disabled = 0;

}



/**

 * usermodehelper_is_disabled - check if new helpers are allowed to be started

 */

bool usermodehelper_is_disabled(void)

{

	return usermodehelper_disabled;

}

EXPORT_SYMBOL_GPL(usermodehelper_is_disabled);



static void helper_lock(void)

{

	atomic_inc(&running_helpers);