From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55978) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fTjgI-0001Ug-Db for qemu-devel@nongnu.org; Fri, 15 Jun 2018 04:02:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fTjgD-0001J1-E9 for qemu-devel@nongnu.org; Fri, 15 Jun 2018 04:02:02 -0400 Received: from 16.mo7.mail-out.ovh.net ([46.105.72.216]:56248) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fTjgD-0001IE-4G for qemu-devel@nongnu.org; Fri, 15 Jun 2018 04:01:57 -0400 Received: from player797.ha.ovh.net (unknown [10.109.105.38]) by mo7.mail-out.ovh.net (Postfix) with ESMTP id 72E92B18D5 for ; Fri, 15 Jun 2018 10:01:55 +0200 (CEST) Date: Fri, 15 Jun 2018 10:01:47 +0200 From: Greg Kurz Message-ID: <20180615100147.0acfa6f2@bahia.lan> In-Reply-To: <20180615090724.6755df6f@bahia.lan> References: <152901299450.252222.14219708016930421485.stgit@bahia.lan> <152901304242.252222.9947658955703347553.stgit@bahia.lan> <20180615000225.GC4129@umbus.fritz.box> <20180615001431.GF4129@umbus.fritz.box> <20180615075805.1213ed06@bahia.lan> <20180615062915.GU4129@umbus.fritz.box> <20180615090724.6755df6f@bahia.lan> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/b3c6DoRnuD26qtmPVPv=FOv"; protocol="application/pgp-signature" Subject: Re: [Qemu-devel] [PATCH 3/5] spapr_cpu_core: add missing rollback on realization path List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson Cc: qemu-devel@nongnu.org, qemu-ppc@nongnu.org, =?UTF-8?B?Q8OpZHJpYw==?= Le Goater --Sig_/b3c6DoRnuD26qtmPVPv=FOv Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 15 Jun 2018 09:07:24 +0200 Greg Kurz wrote: > On Fri, 15 Jun 2018 16:29:15 +1000 > David Gibson wrote: >=20 > > On Fri, Jun 15, 2018 at 07:58:05AM +0200, Greg Kurz wrote: =20 > > > On Fri, 15 Jun 2018 10:14:31 +1000 > > > David Gibson wrote: > > > =20 > > > > On Fri, Jun 15, 2018 at 10:02:25AM +1000, David Gibson wrote: =20 > > > > > On Thu, Jun 14, 2018 at 11:50:42PM +0200, Greg Kurz wrote: =20 > > > > > > The spapr_realize_vcpu() function doesn't rollback in case of e= rror. > > > > > > This isn't a problem with coldplugged CPUs because the machine = won't > > > > > > start and QEMU will exit. Hotplug is a different story though: = the > > > > > > CPU thread is started under object_property_set_bool() and it a= ssumes > > > > > > it can access the CPU object. > > > > > >=20 > > > > > > If icp_create() fails, we return an error without unregistering= the > > > > > > reset handler for this CPU, and we let the underlying QEMU thre= ad for > > > > > > this CPU alive. Since spapr_cpu_core_realize() doesn't care to = unrealize > > > > > > already realized CPUs either, but happily frees all of them any= way, the > > > > > > CPU thread crashes instantly: > > > > > >=20 > > > > > > (qemu) device_add host-spapr-cpu-core,core-id=3D1,id=3Dgku > > > > > > GKU: failing icp_create (cpu 0x11497fd0) > > > > > > ^^^^^^^^^^ > > > > > > Program received signal SIGSEGV, Segmentation fault. > > > > > > [Switching to Thread 0x7fffee3feaa0 (LWP 24725)] > > > > > > 0x00000000104c8374 in object_dynamic_cast_assert (obj=3D0x11497= fd0, > > > > > > ^^^^^^^^^^^^^^ > > > > > > pointer to the CPU= object > > > > > > 623 trace_object_dynamic_cast_assert(obj ? obj->class->= type->name > > > > > > (gdb) p obj->class->type > > > > > > $1 =3D (Type) 0x0 > > > > > > (gdb) p * obj > > > > > > $2 =3D {class =3D 0x10ea9c10, free =3D 0x11244620, > > > > > > ^^^^^^^^^^ > > > > > > should be g_free > > > > > > (gdb) p g_free > > > > > > $3 =3D {} 0x7ffff282bef0 > > > > > >=20 > > > > > > obj is a dangling pointer to the CPU that was just destroyed in > > > > > > spapr_cpu_core_realize(). > > > > > >=20 > > > > > > This patch adds proper rollback to both spapr_realize_vcpu() and > > > > > > spapr_cpu_core_realize(). > > > > > >=20 > > > > > > Signed-off-by: Greg Kurz =20 > > > > >=20 > > > > > Applied to ppc-for-3.0, since it definitely looks to fix some > > > > > problems. =20 > > > >=20 > > > > Uh.. actually it has a definite bug - the first exit point will call > > > > g_free() on an uninitialized spapr_cpu. I fixed it up with a NULL > > > > initialization in my tree. =20 > > >=20 > > > Ah... as said in the cover letter, all the series is based on machine= _data > > > being set before the call to object_property_set_bool()... Maybe I sh= ould > > > have made that explicit with a preparatory patch... Sorry. =20 > >=20 > > Ah, that makes sense. > >=20 > > So, I ended up having to rework a little differently, after I yanked > > by intc -> machine_data patch because it broke things for clg. I > > think I've fixed it up correctly now - if you can check the latest > > ppc-for-3.0 I pushed out, that would be great. > > =20 >=20 > I'll do this ASAP. Oops, I've just spotted a nit in my original patch, that causes QEMU to crash if threads > 1... but I had only tested with single threaded cores :) > +err_unrealize: > + while (--j >=3D 0) { > + spapr_unrealize_vcpu(sc->threads[i]); ^^^ should be j Appart from that, it looks good. --Sig_/b3c6DoRnuD26qtmPVPv=FOv Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEtIKLr5QxQM7yo0kQcdTV5YIvc9YFAlsjcmsACgkQcdTV5YIv c9YOtw//cr2QFFdk4ShML73uyVahVsGcuVHsuoRwDTEV00Td63l4UO019WBnTJck F0W0hCuBMSKR4l//A3uq1KKRU3gljpp2bbhTnnP+2r6bajCXQulwpRcRRqbNHCR8 Hf83tyvm7DjBKpt3Na3PjP1fmHVvzvFLkijwbQjeirmgh6ete2W/ae+LJQnDNYEO uGBbRtnQg8Hu6l4KILzqyXxa7v74dYGwAQgfQYZ8eC5Vd/gZoRuPodQi3/y2Gbb2 CMHHuKlzGKJH8NK0KmQw/UkfySpfEUky5F7zemPGWOEdwRbzu0zWGIpp4baPBs9a aVXsQjQDZma/ut/ZYZ3wqzYYNF2sQ12AkKZNAtSKdo9F5+wvYLfoKacnSEYW/ny/ wOPIDcpjlB83R3Ogkoc1OXoXHqPKmw1JByGPfC8f+vNZl/VTOF3SQAbMYpyzZowq TA1XGqlUkvlPXlIbhRyQJL78G2CkkZ2G/pqy4UhUPVWj/CNCQlYRGxWQo1kdudOy rr7WTsjrwki3z3K7LXv0hEtrcrlOpgbYO6J/s41Hhof6xeacxrBXVRpG1QqEvS4S /pmx7WrFU+C2ngMlXVrEWbBlR8e+Pw2IRrdIb0sPW/L3kraczer2LmhOeu5OF9/g rRkUXqFghdrb95i+lRhUBirX/5qnn5Us4rGzZi1uzL5V2s/f22Q= =cq0V -----END PGP SIGNATURE----- --Sig_/b3c6DoRnuD26qtmPVPv=FOv--