From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
"security@kernel.org" <security@kernel.org>,
X86 ML <x86@kernel.org>, Borislav Petkov <bp@alien8.de>,
Sasha Levin <sasha.levin@oracle.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
xen-devel <xen-devel@lists.xen.org>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH v5 2/4] x86/ldt: Make modify_ldt synchronous
Date: Fri, 31 Jul 2015 12:51:17 -0400 [thread overview]
Message-ID: <55BBA785.2000704@oracle.com> (raw)
In-Reply-To: <CALCETrX7ppxZ5_9hbGwFx7fxe_60t8xVamg62f1Xghi8a68urg@mail.gmail.com>
On 07/30/2015 03:25 PM, Andy Lutomirski wrote:
> On Thu, Jul 30, 2015 at 11:35 AM, Boris Ostrovsky
> <boris.ostrovsky@oracle.com> wrote:
>> [OK] LDT entry 0 has AR 0x0040F200 and limit 0x00000000
>> [OK] LDT entry 0 is invalid
>> [RUN] Cross-CPU LDT invalidation
>> Segmentation fault (core dumped)
> That's not good.
>
> Can you backtrace it? (I.e. compite ldt_gdt_32 with -g and load the
> core dumb in gdb?) My best guesses are either a signal delivery
> failure (although that shouldn't be a problem for 32-bit userspace on
> any kernel) or an actual LDT access fault, and the latter would be
> interesting.
>
> I haven't been able to reproduce this.
This looks like a userspace bug. Breaks on F18, works fine in F22.
Possibly something about signal handling --- I noticed on F18 I'd get
two SEGV's in a row whereas we should only get one.
Anyway, this is not an issue as far as this thread is concerned.
-boris
next prev parent reply other threads:[~2015-07-31 16:52 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-28 5:29 [PATCH v5 0/4] x86: modify_ldt improvement, test, and config option Andy Lutomirski
2015-07-28 5:29 ` Andy Lutomirski
2015-07-28 5:29 ` [PATCH v5 1/4] x86/xen: Unmap aliases in xen_alloc_ldt and xen_free_ldt Andy Lutomirski
2015-07-28 5:29 ` Andy Lutomirski
2015-07-28 5:29 ` [PATCH v5 2/4] x86/ldt: Make modify_ldt synchronous Andy Lutomirski
2015-07-30 7:49 ` Borislav Petkov
2015-07-30 7:49 ` Borislav Petkov
2015-07-30 17:56 ` Boris Ostrovsky
2015-07-30 17:56 ` Boris Ostrovsky
2015-07-30 18:14 ` Andy Lutomirski
2015-07-30 18:14 ` Andy Lutomirski
2015-07-30 18:35 ` Boris Ostrovsky
2015-07-30 18:35 ` Boris Ostrovsky
2015-07-30 19:25 ` Andy Lutomirski
2015-07-31 16:51 ` Boris Ostrovsky [this message]
2015-07-31 16:51 ` Boris Ostrovsky
2015-07-30 19:25 ` Andy Lutomirski
2015-08-13 21:05 ` H. Peter Anvin
2015-08-13 21:05 ` H. Peter Anvin
2015-07-28 5:29 ` Andy Lutomirski
2015-07-28 5:29 ` [PATCH v5 3/4] selftests/x86, x86/ldt: Add a selftest for modify_ldt Andy Lutomirski
2015-07-28 16:53 ` Kees Cook
2015-07-28 16:53 ` Kees Cook
2015-07-28 5:29 ` Andy Lutomirski
2015-07-28 5:29 ` [PATCH v5 4/4] x86/ldt: Make modify_ldt optional Andy Lutomirski
2015-07-28 16:56 ` Kees Cook
2015-07-28 20:03 ` Willy Tarreau
2015-07-28 20:03 ` Willy Tarreau
2015-07-28 20:42 ` Kees Cook
2015-07-28 20:51 ` Willy Tarreau
2015-07-28 20:51 ` Willy Tarreau
2015-07-28 20:42 ` Kees Cook
2015-07-28 16:56 ` Kees Cook
2015-07-28 5:29 ` Andy Lutomirski
2015-07-30 15:53 ` [PATCH v5 0/4] x86: modify_ldt improvement, test, and config option Boris Ostrovsky
2015-07-30 16:05 ` Borislav Petkov
2015-07-30 16:12 ` [Xen-devel] " Andrew Cooper
2015-07-30 16:12 ` Andrew Cooper
2015-07-30 16:31 ` [Xen-devel] " Boris Ostrovsky
2015-07-30 17:06 ` Andrew Cooper
2015-07-30 17:18 ` Boris Ostrovsky
2015-07-30 17:18 ` [Xen-devel] " Boris Ostrovsky
2015-07-31 8:43 ` Borislav Petkov
2015-07-31 8:43 ` [Xen-devel] " Borislav Petkov
2015-07-31 13:42 ` Boris Ostrovsky
2015-07-31 13:42 ` Boris Ostrovsky
2015-07-30 17:06 ` Andrew Cooper
2015-07-30 16:31 ` Boris Ostrovsky
2015-07-30 16:05 ` Borislav Petkov
2015-07-30 15:53 ` Boris Ostrovsky
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