28.10.2015 03:04, Toshi Kani пишет: > On Wed, 2015-10-28 at 07:37 +0900, Linus Torvalds wrote: >> On Tue, Oct 27, 2015 at 11:05 PM, Stas Sergeev <s...@list.ru> wrote: >>> >>> I can't easily post an Oops: under X it doesn't even appear - >>> machine freezes immediately, and under non-KMS console it is >>> possible to get one, but difficult to screen-shot (using bare >>> metal, not VM). Also the Oops was seemingly unrelated. >>> And if you run "dosemu -s" under non-KMS console, you'll also >>> reproduce this one: >>> https://bugzilla.kernel.org/show_bug.cgi?id=97321 >> >> Hmm. Andrew Morton responded to that initially, but then nothing >> happened, and now it's been another six months. Andrew? >> >> The arch/x86/mm/pat.c error handling does seem to be suspect. This is >> all code several years old, so none of this is new, and I think Suresh >> is gone. Adding a few other people with recent sign-offs to that >> file, in the hope that somebody feels like they own it.. > > In the case of PFNMAP, the range should always be mapped. So, I wonder why > follow_phys() failed with the !pte_present() check. > > Stas, do you have a test program that can reproduce 97321? Get dosemu2 from here: https://github.com/stsp/dosemu2/releases or from git, or get dosemu1. Then boot your kernel with "nomodeset=1" to get a text console. Run
dosemu -s and you'll get the bug. You don't even need to mess with FreeDOS or whatever, because the problem happens on a very start. And since it is WARN_OCNCE, you'll need to reboot to get it again. You will probably need to adjust /etc/sudoers because -s means that dosemu (a wrapper script for dosemu.bin) will try sudo so that dosemu.bin can grab /dev/mem as root. If it is too complicated, let me know and I'll try to code up a reduced test-case (but can't promise to get to that quickly). Thanks to everyone (esp Linus of course :-) who got involved in finally supporting dosemu again - it was rather ill for the last years. -- 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/
