Hi Sasha,

On Thu, Jan 9, 2020 at 9:38 PM Sasha Levin sashal@kernel.org wrote:

This is a note to let you know that I've just added the patch titled

ARM: shmobile: defconfig: Restore debugfs support

to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: arm-shmobile-defconfig-restore-debugfs-support.patch and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

commit b56e3b1467eba2ba55bca05e3c8697b23304f12b Author: Geert Uytterhoeven geert+renesas@glider.be Date: Mon Dec 9 11:13:27 2019 +0100

ARM: shmobile: defconfig: Restore debugfs support

[ Upstream commit fa2cdb1762d15f701b83efa60b04f0d04e71bf89 ]

Since commit 0e4a459f56c32d3e ("tracing: Remove unnecessary DEBUG_FS
dependency"), CONFIG_DEBUG_FS is no longer auto-enabled.  This breaks

AFAIK, that commit is not present in v5.4, and hasn't been backported yet. So I don't think there is a need to backport this and all other fixes restoring debugfs support in post-v5.4 kernels.

BTW, I noticed you plan to backport this "fix" not just to v5.4, but also to v4.19?

booting Debian 9, as systemd needs debugfs:

    [FAILED] Failed to mount /sys/kernel/debug.
    See 'systemctl status sys-kernel-debug.mount' for details.
    [DEPEND] Dependency failed for Local File Systems.
    ...
    You are in emergGive root password for maintenance
    (or press Control-D to continue):

Fix this by enabling CONFIG_DEBUG_FS explicitly.

See also commit 18977008f44c66bd ("ARM: multi_v7_defconfig: Restore
debugfs support").

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20191209101327.26571-1-geert+renesas@glider.be
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/arm/configs/shmobile_defconfig b/arch/arm/configs/shmobile_defconfig index c6c70355141c..7e7b678ae153 100644 --- a/arch/arm/configs/shmobile_defconfig +++ b/arch/arm/configs/shmobile_defconfig @@ -215,4 +215,5 @@ CONFIG_DMA_CMA=y CONFIG_CMA_SIZE_MBYTES=64 CONFIG_PRINTK_TIME=y # CONFIG_ENABLE_MUST_CHECK is not set +CONFIG_DEBUG_FS=y CONFIG_DEBUG_KERNEL=y

Gr{oetje,eeting}s,

Geert