Messages in this thread | | | Date | Mon, 17 Dec 2012 09:04:35 +0000 | From | "Jan Beulich" <> | Subject | Re: [GIT PULL] x86/uapi for 3.8 |
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>>> On 15.12.12 at 19:35, Linus Torvalds <torvalds@linux-foundation.org> wrote: > On Sat, Dec 15, 2012 at 8:33 AM, Markus Trippelsdorf > <markus@trippelsdorf.de> wrote: >> On 2012.12.14 at 17:47 -0800, Linus Torvalds wrote: >>> >>> Ho humm. Anybody else see anything strange? >> >> Yes. I'm seeing a BUG early during boot on my machine (RIP=NULL): >> >> BUG: unable to handle kernel NULL pointer dereference at (null) >> >> This is caused by commit 53b87cf088e2 ("x86, mm: Include the >> entire kernel memory map in trampoline_pgd") > > Hmm. That reverts cleanly, and the result boots fine for me. And the > commit looks like exactly the kind of thing that could result in > problems with exactly the right memory layout, so it could explain why > the bisect failed and some kernels randomly worked for me and others > didn't. > > So this at least looks like a very possible candidate. > > Does anybody have an explanation for the problem?
How about this being caused by using the same lower level page table entries that swapper_pg_dir uses, namely including the _PAGE_GLOBAL bits? efi_call_virt_{pre,epi}log() only write CR3 (see 185034e72d591f9465e5e18f937ed642e7ea0070), but would need to also flip CR4.PGE afaict.
Jan
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