Hi Trent,
Il 19/03/2014 07:18, Trent W. Buck ha scritto:
I got it to work, but I had to be evil.
Nice!
sed -i /usr/share/initramfs-tools/init \
-e '\|/run/initramfs$|a/lib/bootchart/bootchart-collector &' \
-e '/^mount.*move.*proc$/ a mount -n -o move /lib/bootchart/tmpfs
${rootmnt}/lib/bootchart/tmpfs'
That is, it starts /lib/bootchart/bootchart-collector *after* /proc
and /dev are mounted (takes about 1s).
This also fixes the problem where bootchart-collector thought it was
"run outside initrd" -- because it does that by reading
/proc/self/mountinfo, so /proc must be mounted first.
Correct
I'm also moving /lib/bootchart/tmpfs inside the pivot.
I'm not sure if that's actually needed.
It should not be needed, if you can test it's not needed it would be helpful
Finally, bootchart-collector --dump needs to the "real" collector process,
so I had to stop banning ptrace with these:
$ cat /etc/sysctl.d/disable-ptrace.conf
kernel/yama/ptrace_scope=3
$ cat /proc/cmdline
[...] security=yama
Yes, ptrace is used to extract collection data from the other process
Attached is my first successful ramdisk trace.
Because I'm waiting for scripts/init to mount proc and dev,
I still lose a full second at the start.
But it works.
I *wasn't* passing rdinit or init at all.
I guess way to clean this up is similar to live-boot's strategy:
boot with "boot=bootchart2 real_boot=local",
where /usr/share/initramfs-tools/bootchart2 goes something like
mountroot() { # -*- shell-script -*-
/lib/bootchart/bootchart-collector &
# FIXME: parse /proc/cmdline here
# Chainload the real mountroot function.
. scripts/${real_boot:-local}
mountroot
# FIXME: is this needed?
mount -omove /lib/bootchart/tmpfs ${rootmnt}/lib/bootchart/tmpfs
}
I don't think the rdinit=/sbin/bootchartd approach will work well,
short of duplicating dozens of lines of code from initramfs-tools'
init.
If you have time to dedicate to that, care to post a patch?
Thanks a lot,
riccardo
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