4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: zhangyi (F) <yi.zhang@xxxxxxxxxx> commit 3df6f61fff49632492490fb6e42646b803a9958a upstream. Commit ea0212f40c6 (power: auto select CONFIG_SRCU) made the code in drivers/base/power/wakeup.c use SRCU instead of RCU, but it forgot to select CONFIG_SRCU in Kconfig, which leads to the following build error if CONFIG_SRCU is not selected somewhere else: drivers/built-in.o: In function `wakeup_source_remove': (.text+0x3c6fc): undefined reference to `synchronize_srcu' drivers/built-in.o: In function `pm_print_active_wakeup_sources': (.text+0x3c7a8): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `pm_print_active_wakeup_sources': (.text+0x3c84c): undefined reference to `__srcu_read_unlock' drivers/built-in.o: In function `device_wakeup_arm_wake_irqs': (.text+0x3d1d8): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `device_wakeup_arm_wake_irqs': (.text+0x3d228): undefined reference to `__srcu_read_unlock' drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs': (.text+0x3d24c): undefined reference to `__srcu_read_lock' drivers/built-in.o: In function `device_wakeup_disarm_wake_irqs': (.text+0x3d29c): undefined reference to `__srcu_read_unlock' drivers/built-in.o:(.data+0x4158): undefined reference to `process_srcu' Fix this error by selecting CONFIG_SRCU when PM_SLEEP is enabled. Fixes: ea0212f40c6 (power: auto select CONFIG_SRCU) Cc: 4.2+ <stable@xxxxxxxxxxxxxxx> # 4.2+ Signed-off-by: zhangyi (F) <yi.zhang@xxxxxxxxxx> [ rjw: Minor subject/changelog fixups ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/power/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -105,6 +105,7 @@ config PM_SLEEP def_bool y depends on SUSPEND || HIBERNATE_CALLBACKS select PM + select SRCU config PM_SLEEP_SMP def_bool y