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On 2020/9/30 18:47, Cyril Hrubis wrote:
<blockquote cite="mid:20200930104709.GC6611@yuki.lan" type="cite">
<pre wrap="">Hi!
</pre>
<blockquote type="cite">
<pre wrap="">When we write '0-' to cpuset.cpus/cpuset.mems, new bitmap_parselist()
in kernel(e.g. newer than v4.2) treats it as an invalid value and old
one treats it as a valid '0':
-------------------------------------------
on v5.8.0:
# echo 0- > cpuset.cpus
-bash: echo: write error: Invalid argument
# echo 0- > cpuset.mems
-bash: echo: write error: Invalid argument
on v4.0.0:
# echo '0-' >cpuset.cpus
# cat cpuset.cpus
0
# echo '0-' >cpuset.mems
# cat cpuset.cpus
0
-------------------------------------------
Note: commit d9282cb66353b changes the behavior.
Drop the check of kernel version and accept either 0 or -EINVAL
because the change of behavior can be backported into old kernel.
</pre>
</blockquote>
<pre wrap="">
Why can't we just simply adjust the kernel check, it looks like the
commit you mentioned was added to 4.3 so it should be fixed by changing
the line to:
if tst_kvcmp -lt "4.3 RHEL6:2.6.32"; then
We want to at least keep the check for kernels newer than 4.3 just to
make sure that kernel keeps rejecting the '0-' invalid value.
</pre>
</blockquote>
Hi Cyril,<br>
<br>
Thanks for your reply. <span class="moz-smiley-s1"><span> :-) </span></span><br>
1) I still got '0' value instead of -EINVAL on Centos
6.10(2.6.32-754) so not sure why we have the wrong kernel check
before.<br>
Perhaps, is there anothe older kernel commit to change the
behavior as well?<br>
2) I don't think that kernel check is enough because the change of
behavior may be backported into old kernel.<br>
<br>
How about removing the combination directly as Richard suggested on
#695.<br>
<br>
Best Regards,<br>
Xiao Yang<br>
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