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: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
index 8c798ef..bbb03e6 100644
--- a/drivers/base/firmware_class.c
+++ b/drivers/base/firmware_class.c
@@ -521,6 +521,11 @@
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",
diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 6efd7a7..7f3dbcb 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -111,7 +111,12 @@
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__ */
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 9cd0591..9ab513b 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -301,6 +301,15 @@
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);
