Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: KASLR causes intermittent boot failures on some systems | Date | Mon, 10 Apr 2017 15:18:14 -0400 |
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Kees Cook <keescook@chromium.org> writes:
> On Mon, Apr 10, 2017 at 11:22 AM, Jeff Moyer <jmoyer@redhat.com> wrote: >> Kees Cook <keescook@chromium.org> writes: >> >>> On Mon, Apr 10, 2017 at 8:49 AM, Jeff Moyer <jmoyer@redhat.com> wrote: >>>> Kees Cook <keescook@chromium.org> writes: >>>> >>>>> On Fri, Apr 7, 2017 at 7:41 AM, Jeff Moyer <jmoyer@redhat.com> wrote: >>>>>> Hi, >>>>>> >>>>>> commit 021182e52fe01 ("x86/mm: Enable KASLR for physical mapping memory >>>>>> regions") causes some of my systems with persistent memory (whether real >>>>>> or emulated) to fail to boot with a couple of different crash >>>>>> signatures. The first signature is a NMI watchdog lockup of all but 1 >>>>>> cpu, which causes much difficulty in extracting useful information from >>>>>> the console. The second variant is an invalid paging request, listed >>>>>> below. >>>>> >>>>> Just to rule out some of the stuff in the boot path, does booting with >>>>> "nokaslr" solve this? (i.e. I want to figure out if this is from some >>>>> of the rearrangements done that are exposed under that commit, or if >>>>> it is genuinely the randomization that is killing the systems...) >>>> >>>> Adding "nokaslr" to the boot line does indeed make the problem go away. >>> >>> Are you booting with a memmap= flag? >> >> From my first email: >> >> [ 0.000000] Command line: BOOT_IMAGE=/vmlinuz-4.11.0-rc5+ >> root=/dev/mapper/rhel_intel--lizardhead--04-root ro memmap=192G!1024G >> crashkernel=auto rd.lvm.lv=rhel_intel-lizardhead-04/root >> rd.lvm.lv=rhel_intel-lizardhead-04/swap console=ttyS0,115200n81 >> LANG=en_US.UTF-8 >> >> Did you not receive the attachments? > > I see it now, thanks! > > The memmap parsing was added in -rc1 (f28442497b5ca), so I'd expect > that to be handled. Hmmm.
I can also reproduce this on a system with real persistent memory, which does not require the memmap parameter.
Cheers, Jeff
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