Messages in this thread | | | Date | Mon, 1 May 2017 19:32:32 +0800 | From | Baoquan He <> | Subject | Re: KASLR causes intermittent boot failures on some systems |
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Hi,
The root cause has been found out finally. It's caused by code bug in sync_global_pgds which is wrong for loop count calculation.
Will post patch.
Thanks Baoquan
On 04/07/17 at 10:41am, Jeff Moyer 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. > > On some systems, I haven't hit this problem at all. Other systems > experience a failed boot maybe 20-30% of the time. To reproduce it, > configure some emulated pmem on your system. You can find directions > for that here: https://nvdimm.wiki.kernel.org/ > > Install ndctl (https://github.com/pmem/ndctl). > Configure the namespace: > # ndctl create-namespace -f -e namespace0.0 -m memory > > Then just reboot several times (5 should be enough), and hopefully > you'll hit the issue. > > I've attached both my .config and the dmesg output from a successful > boot at the end of this mail. >
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