This option was removed by "make savedefconfig" in commit c5054a98bce4 ("ARM: imx_v6_v7_defconfig: Select SMSC_PHY")
This happened because CONFIG_DEBUG_FS was implicitly selected by CONFIG_TREE_RCU_TRACE which defaulted to true because CONFIG_RCU_TRACE was enabled by default by commit 961518259b3b ("rcu: Enable RCU tracepoints by default to aid in debugging") Recently however CONFIG_RCU_TRACE was completely removed by commit 6e74c237c410 ("rcu: Remove debugfs tracing") The result is that imx_v6_v7_defconfig no longer includes DEBUG_FS on linux-next since next-20170517. This is bad, DEBUG_FS is extremely useful for kernel introspection and testing. Signed-off-by: Leonard Crestez <leonard.cres...@nxp.com> --- Patch is against next-20170526. Applying it to shawnguo/imx/defconfig and cycling via savedefconfig makes this diff go away. Alternatively maybe DEBUG_FS itself could be made "default y if DEBUG_KERNEL" or similar? arch/arm/configs/imx_v6_v7_defconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig index bf1e7e3..51ca814 100644 --- a/arch/arm/configs/imx_v6_v7_defconfig +++ b/arch/arm/configs/imx_v6_v7_defconfig @@ -381,6 +381,7 @@ CONFIG_NLS_ISO8859_1=y CONFIG_NLS_ISO8859_15=m CONFIG_NLS_UTF8=y CONFIG_PRINTK_TIME=y +CONFIG_DEBUG_FS=y CONFIG_MAGIC_SYSRQ=y # CONFIG_SCHED_DEBUG is not set CONFIG_PROVE_LOCKING=y -- 2.7.4