Hi Eric,
On Fri, 16 Apr 2021 at 23:27, Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
>
> On Thu, 15 Apr 2021 10:37:53 -0700 Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@xxxxxxxxxx>
> >
> > Calling two copy_to_user() for very small regions has very high overhead.
> >
> > Switch to inlined unsafe_put_user() to save one stac/clac sequence,
> > and avoid copy_to_user().
> >
> > Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> > Cc: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
>
> Hi Eric!
>
> This appears to break boot on my systems.
I have been noticing this problem.
>
> IDK how exactly, looks like systemd gets stuck waiting for nondescript
> services to start in initramfs. I have lots of debug enabled and didn't
> spot anything of note in kernel logs.
We (LKFT) are still seeing this problem only on arm architecture on
next-20210416 tag onwards. our bisect script points to this commit.
Steps to reproduce:
- build linux next latest next-20210423 tag with below config
- kernel-config:
https://builds.tuxbuild.com/1reqrnNLnHEX9uEZFngRfaoJa9E/config
- boot qemu-arm with below command
- /usr/bin/qemu-system-aarch64 -cpu host,aarch64=off -machine
virt-2.10,accel=kvm -nographic -net
nic,model=virtio,macaddr=BA:DD:AD:CC:09:04 -net tap -m 2048 -monitor
none -kernel zImage --append "console=ttyAMA0 root=/dev/vda rw" -hda
rpb-console-image-lkft-am57xx-evm-20201022181203-3085.rootfs.ext4 -m
4096 -smp 2 -nographic
- After the mount rootfs - the systemd gets stuck
>
> I'll try to poke at this more, but LMK if you have any ideas. The
> commit looks "obviously correct" :S
May I request to investigate this on arm architecture.
The qemu_arm boot failed link,
https://lkft.validation.linaro.org/scheduler/job/2565371#L540
The qemu_arm boot pass after the reverting this patch,
commit 38ebcf5096a86762b82262e96b2c8b170fe79040
scm: optimize put_cmsg()
on the latest linux next tags i have to revert two commits.
"scm: fix a typo in put_cmsg()"
"scm: optimize put_cmsg()"
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
--
Linaro LKFT
https://lkft.linaro.org
