>>> On 15.12.12 at 19:35, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Sat, Dec 15, 2012 at 8:33 AM, Markus Trippelsdorf > <mar...@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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/