On 03/21/17 at 10:18pm, Eric W. Biederman wrote: > Dave Young <dyo...@redhat.com> writes: > > > On 03/20/17 at 10:33pm, Eric W. Biederman wrote: > >> Xunlei Pang <xlp...@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.
Yes, need careful review from s390 and maybe ppc64 especially about patch 2/3, better to have comments from IBM about s390 dump tool and ppc fadump. Added more cc. Thanks Dave
