Dave Young <dyoung at redhat.com> writes: > On 03/20/17 at 10:33pm, Eric W. Biederman wrote: >> Xunlei Pang <xlpang at redhat.com> writes: >> >> > As Eric said, >> > "what we need to do is move the variable vmcoreinfo_note out >> > of the kernel's .bss section. And modify the code to regenerate >> > and keep this information in something like the control page. >> > >> > Definitely something like this needs a page all to itself, and ideally >> > far away from any other kernel data structures. I clearly was not >> > watching closely the data someone decided to keep this silly thing >> > in the kernel's .bss section." >> > >> > This patch allocates extra pages for these vmcoreinfo_XXX variables, >> > one advantage is that it enhances some safety of vmcoreinfo, because >> > vmcoreinfo now is kept far away from other kernel data structures. >> >> Can you preceed this patch with a patch that removes CRASHTIME from >> vmcoreinfo? If someone actually cares we can add a separate note that holds >> a 64bit crashtime in the per cpu notes. > > I think makedumpfile is using it, but I also vote to remove the > CRASHTIME. It is better not to do this while crashing and a makedumpfile > userspace patch is needed to drop the use of it. > >> >> As we are looking at reliability concerns removing CRASHTIME should make >> everything in vmcoreinfo a boot time constant. Which should simplify >> everything considerably. > > It is a nice improvement.. We also need to take a close look at what s390 is doing with vmcoreinfo. As apparently it is reading it in a different kind of crashdump process. Eric
