Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751946AbaBLLJt (ORCPT ); Wed, 12 Feb 2014 06:09:49 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45491 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750916AbaBLLJs (ORCPT ); Wed, 12 Feb 2014 06:09:48 -0500 Message-ID: <52FB5669.7090506@canonical.com> Date: Wed, 12 Feb 2014 12:09:29 +0100 From: Stefan Bader User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Borislav Petkov , Peter Zijlstra CC: Paolo Bonzini , Linux Kernel Mailing List , kvm@vger.kernel.org, Marcelo Tosatti , MASAO TAKAHASHI , Joerg Roedel Subject: Re: Another preempt folding issue? References: <52FA6D4B.7020709@canonical.com> <20140211194553.GZ9987@twins.programming.kicks-ass.net> <52FB2EC8.4080602@canonical.com> <20140212103713.GE3545@laptop.programming.kicks-ass.net> <20140212104017.GA5121@pd.tnic> In-Reply-To: <20140212104017.GA5121@pd.tnic> X-Enigmail-Version: 1.5.2 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Nd88WwcH8QdC3vsQgfCHI1Nc4vRtrunmO" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Nd88WwcH8QdC3vsQgfCHI1Nc4vRtrunmO Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 12.02.2014 11:40, Borislav Petkov wrote: > On Wed, Feb 12, 2014 at 11:37:13AM +0100, Peter Zijlstra wrote: >>> Another reporter also saw this on an AMD and said it could not be rep= roduced on >>> the same hardware and the same software versions when using 64bit ins= tead of 32. >>> >>> In my case on a 32bit installation I will see this on every invocatio= n of >> >> Curious.. so its both AMD and Intel. >> >> That makes funny hardware less likely... but how can the vmexit loose = an >> interrupt like this. >=20 > Also what I'm wondering about and what's not clear from Stefan's reply > is whether this is purely a 32-bit issue, i.e. a 32-bit host running a > 64-bit qemu running a 32-bit iso or what is it? >=20 > Or do we have reports for both 32-bit and 64-bit hosts? Only for 32bit hosts. I have not tested a 64bit kernel plus 32bit userspa= ce, though. But 64bit kernel and 64bit user-space seemed ok. And one detail I= should add is that while the reproduction is possible in all attempts, the timin= g can vary. In some of the cases this was even before running a Linux kernel in= the guest. Something else here I run a kernel with CONFIG_PREEMPT not set and NR_CPU= S limited to 8 (for the 32bit kernel). So the default apic driver is used. = Since default_send_IPI_mask_logical is only used from there, I assume the trace= you got does the same. Maybe something there is wrong which would explain why= we only see it on 32bit hosts. >=20 > Thanks. >=20 --Nd88WwcH8QdC3vsQgfCHI1Nc4vRtrunmO Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCgAGBQJS+1ZpAAoJEOhnXe7L7s6jXRkP/20KwL982Gr7iICGkEQOMt3L wfxjpeQmn7hUTE3HAtcESbFxNeyrSlv5D3vY0gQniItRYeP5z7xKLCkE68SYMSv3 z6QUha4PaOApOTzjr+j/YcmxdqVex/qVQNOYhsn/F1WCFLY+XfBWigJWOs7+LZ3I x3tfim2G+uYoAwLNl1rdTnW1DuJkAmqq22M5GnPvEA3xHC96KuKyAilcigP+/LPZ kA+wVjpKkFeFic2fX2NWotZhqwU4CoP6+Ae4HyTj7rnibPl5g3BQsdYzwsADdgIF MMdCOh/nSDmJRaor6bbvVbxbBHw0Qx+ZGCxhPRtEgv440pbRuEIN0oYJrMe/N32Z 9SMZTzGpQcSUd6bGmYA/rf7VR2pgdjqitTLUTKhbHNsAoxnTWc8SIeiDlHjzLqvJ KoogE4vV79rnu5gwzIEqXIYmiIpYFMX+1zFZkmjRD3ZCO1gKfLrSSLW89LjrULvD r7ewfC4n5wcZS7P3vOdcJOpxxeznBiUwxPtkmYSCNIZqKTyF9RTDwDWgCI1RDzwB 7S+MEu8Y7Gjtv5HXAijxzO6lKLGMqk4Z0dzrnzdu8ZvZq8MsLPaMXH1f5nPI+XZu zBls8GNaC0bQ0xHjXzVxtdLxxIZyH4RKho1oXXEeP+QIxh0Q/sSa2TIKZP8/1qDj JK14tT+EdCDQutJT5oud =ZnxX -----END PGP SIGNATURE----- --Nd88WwcH8QdC3vsQgfCHI1Nc4vRtrunmO-- -- 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/