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Groups > linux.kernel > #1259975
| From | Stas Sergeev <stsp@list.ru> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: 4.3 regression: task_work corruption in vm86 mode? |
| Date | 2015-10-31 13:00 +0100 |
| Message-ID | <qpCZb-2lV-1@gated-at.bofh.it> (permalink) |
| References | <qptsR-4Wn-3@gated-at.bofh.it> <qpxd7-7ms-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
31.10.2015 08:43, Andy Lutomirski пишет: > On Fri, Oct 30, 2015 at 6:44 PM, Andy Lutomirski <luto@amacapital.net> wrote: >> Hi all- >> >> In 4.3-rc7, running dosemu2 (https://github.com/stsp/dosemu2/) oopses >> the system very quickly, as long as CONFIG_VM86=y. It blows up >> because snd_seq_delete_port walks ports_list_head, finds two valid >> ports, and then starts finding obviously invalid pointers in the list. >> >> git bisect blames: >> >> commit 5ed92a8ab71f8865ba07811429c988c72299b315 >> Author: Brian Gerst <brgerst@gmail.com> >> Date: Wed Jul 29 01:41:19 2015 -0400 >> >> x86/vm86: Use the normal pt_regs area for vm86 >> >> I haven't spotted the problem yet. It seems to happen when >> task_work_run fires in get_signal, which happens before >> save_v86_state. I'm not entirely sure what causes task work to be >> scheduled at all while in v86 land. Could we somehow be processing >> task_work later than we should? >> > Nope, the bug has nothing to do with task_work. Patches sent. Andy, thanks for finally fixing this attack surface! So after all, the comments you put into Kconfig, were justified. Now I can seriously consider the dosemu2-specific vm86-light. Having the machine to crash, was not a good starting point for the clean-ups. Also there is an interesting thread here: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1499089 I wonder if they are affected now by that bug or not... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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4.3 regression: task_work corruption in vm86 mode? Andy Lutomirski <luto@amacapital.net> - 2015-10-31 02:50 +0100
Re: 4.3 regression: task_work corruption in vm86 mode? Andy Lutomirski <luto@amacapital.net> - 2015-10-31 06:50 +0100
Re: 4.3 regression: task_work corruption in vm86 mode? Stas Sergeev <stsp@list.ru> - 2015-10-31 13:00 +0100
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