<div dir="ltr">Got it! thx!</div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, May 28, 2015 at 11:43 AM,  <span dir="ltr">&lt;<a href="mailto:Valdis.Kletnieks@vt.edu" target="_blank">Valdis.Kletnieks@vt.edu</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Thu, 28 May 2015 11:26:02 +0800, Gao Peng said:<br>
&gt;<br>
&gt; I am not sure if I boot from the old kernel,will the old kernel load the<br>
</span>&gt; new-installed modules or keep it&#39;s own modules.<br>
<br>
If you did it properly, then you should have 2 kernels, each with a<br>
distinct value for uname -r, and 2 directories under /lib/modules, one<br>
for each kernel.  Each kernel then proceeds to load modules from<br>
/lib/modules/`uname -r`.<br>
<br>
So if you have a 3.19.0 kernel, and a 4.0.1 kernel, they&#39;ll both be<br>
sitting in /boot (each with its own initramfs, probably), and<br>
the 3.19.0 will load from /lib/modules/3.19.0 and the 4.0.1 will load<br>
from /lib/modules/4.0.1<br>
<br>
And, of course, you hopefully have grub/grub2/whatever configured to allow<br>
you to select a kernel by having multiple definition stanzas, one per<br>
kernel...<br>
<br>
Extreme example (I keep a *lot* of kernels around because I keep breaking them):<br>
<br>
[~] ls /boot/vmlinuz-[34]*<br>
/boot/vmlinuz-3.17.0-0.rc6.git2.1.fc22.x86_64  /boot/vmlinuz-4.0.0-rc3-next-20150310-dirty<br>
/boot/vmlinuz-3.18.0-0.rc3.git0.1.fc22.x86_64  /boot/vmlinuz-4.0.0-rc5-next-20150324<br>
/boot/vmlinuz-3.19.0-0.rc3.git2.1.fc22.x86_64  /boot/vmlinuz-4.0.0-rc6-next-20150331<br>
/boot/vmlinuz-4.0.0-next-20150421              /boot/vmlinuz-4.1.0-rc1-next-20150428<br>
/boot/vmlinuz-4.0.0-rc1-next-20150224          /boot/vmlinuz-4.1.0-rc2-next-20150506<br>
/boot/vmlinuz-4.0.0-rc1-next-20150226-dirty    /boot/vmlinuz-4.1.0-rc4-next-20150521<br>
/boot/vmlinuz-4.0.0-rc1-next-20150303-dirty    /boot/vmlinuz-4.1.0-rc5-next-20150526<br>
/boot/vmlinuz-4.0.0-rc2-next-20150306-dirty<br>
[~] ls /boot/initramfs-[34]*<br>
/boot/initramfs-3.17.0-0.rc6.git2.1.fc22.x86_64.img  /boot/initramfs-4.0.0-rc3-next-20150310-dirty.img<br>
/boot/initramfs-3.18.0-0.rc3.git0.1.fc22.x86_64.img  /boot/initramfs-4.0.0-rc5-next-20150324.img<br>
/boot/initramfs-3.19.0-0.rc3.git2.1.fc22.x86_64.img  /boot/initramfs-4.0.0-rc6-next-20150331.img<br>
/boot/initramfs-4.0.0-next-20150421.img              /boot/initramfs-4.1.0-rc1-next-20150428.img<br>
/boot/initramfs-4.0.0-rc1-next-20150224.img          /boot/initramfs-4.1.0-rc2-next-20150506.img<br>
/boot/initramfs-4.0.0-rc1-next-20150226-dirty.img    /boot/initramfs-4.1.0-rc4-next-20150521.img<br>
/boot/initramfs-4.0.0-rc1-next-20150303-dirty.img    /boot/initramfs-4.1.0-rc5-next-20150526.img<br>
/boot/initramfs-4.0.0-rc2-next-20150306-dirty.img<br>
[~] ls /lib/modules<br>
3.17.0-0.rc6.git2.1.fc22.x86_64  4.0.0-rc1-next-20150224        4.0.0-rc3-next-20150310-dirty  4.1.0-rc2-next-20150506<br>
3.18.0-0.rc3.git0.1.fc22.x86_64  4.0.0-rc1-next-20150226-dirty  4.0.0-rc5-next-20150324        4.1.0-rc4-next-20150521<br>
3.19.0-0.rc3.git2.1.fc22.x86_64  4.0.0-rc1-next-20150303-dirty  4.0.0-rc6-next-20150331        4.1.0-rc5-next-20150526<br>
4.0.0-next-20150421              4.0.0-rc2-next-20150306-dirty  4.1.0-rc1-next-20150428<br>
<br>
Hope that helps it make sense...<br>
</blockquote></div><br></div>