From owner-freebsd-current@FreeBSD.ORG Mon Aug 12 16:01:55 2013 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 9C2E218B; Mon, 12 Aug 2013 16:01:55 +0000 (UTC) (envelope-from david@catwhisker.org) Received: from albert.catwhisker.org (mx.catwhisker.org [198.144.209.73]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 4836F293B; Mon, 12 Aug 2013 16:01:54 +0000 (UTC) Received: from albert.catwhisker.org (localhost [127.0.0.1]) by albert.catwhisker.org (8.14.7/8.14.7) with ESMTP id r7CG1sbB007938; Mon, 12 Aug 2013 09:01:54 -0700 (PDT) (envelope-from david@albert.catwhisker.org) Received: (from david@localhost) by albert.catwhisker.org (8.14.7/8.14.7/Submit) id r7CG1sGl007937; Mon, 12 Aug 2013 09:01:54 -0700 (PDT) (envelope-from david) Date: Mon, 12 Aug 2013 09:01:54 -0700 From: David Wolfskill To: Davide Italiano Subject: Re: Early drop to debugger with DEBUG_MEMGUARD Message-ID: <20130812160154.GF1570@albert.catwhisker.org> References: <20130812151314.GE1570@albert.catwhisker.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="XIiC+We3v3zHqZ6Z" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Cc: current@freebsd.org X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Aug 2013 16:01:55 -0000 --XIiC+We3v3zHqZ6Z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Aug 12, 2013 at 08:30:15AM -0700, Davide Italiano wrote: > ... > > Booting... > > GDB: no debug ports present > > KDB: debugger backends: ddb > > KDB: current backend: ddb > > Copyright (c) 1992-2013 The FreeBSD Project. > > Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 > > The Regents of the University of California. All rights reserve= d. > > FreeBSD is a registered trademark of The FreeBSD Foundation. > > FreeBSD 10.0-CURRENT #0 r254245M/254246:1000042: Mon Aug 12 07:20:47 P= DT 2013 > > root@freebeast.catwhisker.org:/common/S3/obj/usr/src/sys/MEMGUARD i= 386 > > FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610 > > WARNING: WITNESS option enabled, expect reduced performance. > > panic: Assertion strat =3D=3D M_BESTFIT || strat =3D=3D M_FIRSTFIT fail= ed at /usr/src/sys/kern/subr_vmem.c:1050 > > cpuid =3D 0 > > KDB: stack backtrace: > > db_trace_self_wrapper(c116fcdc,73752f20,72732f72,79732f63,656b2f73,...)= at db_trace_self_wrapper+0x2d/frame 0xc1820ba0 > > kdb_backtrace(c11c4b23,0,c0f8a835,c1820c74,c0f8a835,...) at kdb_backtra= ce+0x30/frame 0xc1820c08 > > vpanic(c12eea08,100,c0f8a835,c1820c74,c1820c74,...) at vpanic+0x11f/fra= me 0xc1820c44 > > kassert_panic(c0f8a835,c1172e98,c1172e39,41a,8,...) at kassert_panic+0x= ea/frame 0xc1820c68 > > vmem_alloc(c130d680,6681000,2,c1820cc0,3b5,...) at vmem_alloc+0x53/fram= e 0xc1820ca0 > > memguard_init(c130d680,c0a9fa50,c6800000,20281000,1000,10000,0) at memg= uard_init+0x29/frame 0xc1820cc4 > > kmeminit(c14b9fd4,c10efc89,0,0,c1820d30,...) at kmeminit+0x171/frame 0x= c1820cf0 > > mallocinit(0,0,2,0,c11d3728,...) at mallocinit+0x32/frame 0xc1820d30 > > mi_startup() at mi_startup+0xf7/frame 0xc1820d58 > > begin() at begin+0x2c > > KDB: enter: panic > > [ thread pid 0 tid 0 ] > > Stopped at kdb_enter+0x3d: movl $0,kdb_why > > db> > > > > As you can see, this is well before any device probes or much of > > anything else. Thus, I suspect that it's fairly possible that the > > assertion may well be OK after a certain point in the boot sequence, > > but decidedly *not* OK in this specific instance. Or perhaps the > > assertion just doesn't play well with DEBUG_MEMGUARD. > ... > vmem_alloc() KPI needs the consumer to specify exactly a strategy for > allocation, which is one of two between: M_FIRSTFIT/M_BESTFIT (fast > allocation vs low fragmentation), and that's the assertion that's not > respected within the code. >=20 > 1050 MPASS(strat =3D=3D M_BESTFIT || strat =3D=3D M_FIRSTFIT); >=20 > It looks like memguard_init() doesn't specify none of these two strategie= s. >=20 > 209 vmem_alloc(parent, memguard_mapsize, M_WAITOK, &base); >=20 > My guess is that you need to OR one between M_BESTFIT/M_FIRSTFIT with > M_WAITOK to have your kernel booting. What's better between the two > probably will need some measurements but this should at least make > your kernel booting. Thank you for the insight & suggestion. My first attempt was to make the following change: Index: sys/vm/memguard.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- sys/vm/memguard.c (revision 254246) +++ sys/vm/memguard.c (working copy) @@ -206,9 +206,9 @@ { vm_offset_t base; =20 - vmem_alloc(parent, memguard_mapsize, M_WAITOK, &base); + vmem_alloc(parent, memguard_mapsize, M_WAITOK | M_FIRSTFIT, &base); memguard_map =3D vmem_create("memguard arena", base, memguard_mapsize, - PAGE_SIZE, 0, M_WAITOK); + PAGE_SIZE, 0, M_WAITOK | M_FIRSTFIT); memguard_cursor =3D base; memguard_base =3D base; =20 This built OK; but attempting to boot yielded: Booting... GDB: no debug ports present KDB: debugger backends: ddb KDB: current backend: ddb Copyright (c) 1992-2013 The FreeBSD Project. Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994 The Regents of the University of California. All rights reserved. FreeBSD is a registered trademark of The FreeBSD Foundation. FreeBSD 10.0-CURRENT #1 r254245M/254246:1000042: Mon Aug 12 08:49:12 PDT 2= 013 root@freebeast.catwhisker.org:/common/S3/obj/usr/src/sys/MEMGUARD i386 FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610 WARNING: WITNESS option enabled, expect reduced performance. panic: mti_zone 195 out of range 8 cpuid =3D 0 KDB: stack backtrace: db_trace_self_wrapper(c116fcdc,0,ffffffff,c1167d73,fffffffe,...) at db_trac= e_self_wrapper+0x2d/frame 0xc1820b58 kdb_backtrace(c11c4b23,0,c1167d58,c1820c30,c1820c00,...) at kdb_backtrace+0= x30/frame 0xc1820bc0 vpanic(c12eea08,100,c1167d58,c1820c30,c1820c30,...) at vpanic+0x11f/frame 0= xc1820c00 kassert_panic(c1167d58,c3,8,c130d7e4,c130d7a8,...) at kassert_panic+0xea/fr= ame 0xc1820c24 malloc(380,c1279778,2,0,ffffffff,...) at malloc+0x308/frame 0xc1820c70 vmem_create(c11a7530,c6800000,6681000,1000,0,...) at vmem_create+0x29/frame= 0xc1820ca0 memguard_init(c130d680,c0a9fa50,c6800000,20281000,1000,10000,0) at memguard= _init+0x5e/frame 0xc1820cc4 kmeminit(c14b9fd4,c10efc89,0,0,c1820d30,...) at kmeminit+0x171/frame 0xc182= 0cf0 mallocinit(0,0,2,0,c11d3728,...) at mallocinit+0x32/frame 0xc1820d30 mi_startup() at mi_startup+0xf7/frame 0xc1820d58 begin() at begin+0x2c KDB: enter: panic [ thread pid 0 tid 0 ] Stopped at kdb_enter+0x3d: movl $0,kdb_why db>=20 grepping through the sources indicates to me that I/we have run afoul of: =2E/kern/kern_malloc.c-504- if (size & KMEM_ZMASK) =2E/kern/kern_malloc.c-505- size =3D (size & ~KMEM_ZM= ASK) + KMEM_ZBASE; =2E/kern/kern_malloc.c-506- indx =3D kmemsize[size >> KMEM_ZS= HIFT]; =2E/kern/kern_malloc.c:507: KASSERT(mtip->mti_zone < numzones, =2E/kern/kern_malloc.c:508: ("mti_zone %u out of range %d= ", =2E/kern/kern_malloc.c:509: mtip->mti_zone, numzones)); =2E/kern/kern_malloc.c:510: zone =3D kmemzones[indx].kz_zone[= mtip->mti_zone]; =2E/kern/kern_malloc.c-511-#ifdef MALLOC_PROFILE =2E/kern/kern_malloc.c-512- krequests[size >> KMEM_ZSHIFT]++; =2E/kern/kern_malloc.c-513-#endif Hmm.... Peace, david --=20 David H. Wolfskill david@catwhisker.org Taliban: Evil men with guns afraid of truth from a 14-year old girl. See http://www.catwhisker.org/~david/publickey.gpg for my public key. --XIiC+We3v3zHqZ6Z Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.20 (FreeBSD) iEYEARECAAYFAlIJBvEACgkQmprOCmdXAD0WqQCbBL7CdQvKDG8gWwmDjEXMqgV0 B0AAn2xZD22CxdHLChwQfr351NyGONFh =nDTz -----END PGP SIGNATURE----- --XIiC+We3v3zHqZ6Z--