From owner-freebsd-toolchain@freebsd.org Sat Jun 8 22:57:43 2019 Return-Path: Delivered-To: freebsd-toolchain@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8F0F815B5EE4 for ; Sat, 8 Jun 2019 22:57:43 +0000 (UTC) (envelope-from marklmi@yahoo.com) Received: from sonic308-55.consmr.mail.gq1.yahoo.com (sonic308-55.consmr.mail.gq1.yahoo.com [98.137.68.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 8942876D2A for ; Sat, 8 Jun 2019 22:57:41 +0000 (UTC) (envelope-from marklmi@yahoo.com) X-YMail-OSG: 4YUs_PEVM1mkICEVBTlWkmvkBnGSClKatR0wmAjoFslvHAQZ8vafRCyPLf8yPZG yGxchp3L5TKSr_7Oh3r1pBBcc1kK0WHkl1bEp0V80iSLV64ilWWyZzNhCcjsHkbMWvEG5DfZKsK. YLIRh6PBvypvBLozsxEYYPlA8qCyT3Foj1Cvx8t8jzzPK2j66aK3Fg91eqcSpxNZZwOyE.e0cQ5y .z0zfLt.wrjz2bgCBWrqHaRvQDiD89nrImmzIuJbwtSZG_Eati9zv._4kJX8vNMDO4MoRwrf6LHD ZGvBeuMtxbJIPgag795CSY0oJlRShjgapseDfgk17.36CtkvoPhGymX_0sGkEYzB3tOOJxJfACue EjXk.c545sFgzAs5B4t.vQe6QqsngmI2oxhZA.WVlDFHA4wM_oQL8g9PryYdcI_buGyv0UuKHJnJ PYx_OxHWypUG7mfTvf7n8QN7NMi1_OmMOTWpWK38K.BgwvbuZa3qGF_mFrEG.2MKygANMjGOWUj4 1DZ6My4_5Kzs64ZqYhwc8FQm7iNsC9hATAWNLQRNZWpYuGOjekzUQ_b8VZQLbMtxlTWYkbfL9GRp 6eTKQ0mEcNBKb5RotPwjfuG34C44Vo32eK9CzT3nM0u0As4cIm.fAmGCXhRx.DSvYe53f8X5EcMK sF_t2pxLTmALufbClPDNUXcIVtjISDLLRJucnbzsucDybV5Su5l4ULeIgXWI5Gmc_y8OQOtiCysr P4CXJdoV4goNmf6GoDQ9SO5Z5xdOZ8bjLh0R7WA_8nfVgoQtNckEZmQTZHsq9_CqOSlfh3XC4JbK Ba3q9v29qYlzJD3KS9GY4c6F9ZkYsM.6wh5PeGt8TiNzpRyt7O7UOss2KPCVHV6CINfxT3tVKdDh 6lxrgrjcK4qeMX.uxT_9_I.4x73vnauFCacsBXs.oKXMr9X5j9DcIYoVV0eivVGSxIz_Xx7t7U1X zbR12w.Qg6nQ_HdGr1_kxgr36WSN3R2sq5iPalqT6Cg.5tQqewpnwN8IVPXu7Bx8tZSPeA3Cdaql zgdOwlkd6H3KbvVrhushmKgIxZuRe5yj4AGZrVxmKH8aRVklMaVBrSCAd3GbkELkLufJi.HDt0CS fQRNF2o7Xy0xVQq7mtEadNthg8Af5X4LcgEnDEEFhwDx2saAAbEk5w6M7oDZyLseJ_HPAxFucPZB 2Z.vAPaGz7v5WJY0g.FAl2STaFN2vxNT7yxi9zxXqPkrYi0h9LtkeMSZETIJzMwE.IE08g8g- Received: from sonic.gate.mail.ne1.yahoo.com by sonic308.consmr.mail.gq1.yahoo.com with HTTP; Sat, 8 Jun 2019 22:57:39 +0000 Received: from c-67-170-167-181.hsd1.or.comcast.net (EHLO [192.168.1.115]) ([67.170.167.181]) by smtp429.mail.gq1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 306e6b2d3c75727293f2733e49d52872; Sat, 08 Jun 2019 22:37:22 +0000 (UTC) From: Mark Millard Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.11\)) Subject: crash of 32-bit powerpc -r347549 kernel built via system-clang-8, _init_tls is where the initial DIAGNOSTICS-reported SIGSEGV happens Message-Id: <8F272F27-0BC3-402A-810A-4608162F9EEE@yahoo.com> Date: Sat, 8 Jun 2019 15:37:21 -0700 Cc: Alfredo Dal Ava Junior , Justin Hibbits To: FreeBSD Toolchain , FreeBSD PowerPC ML X-Mailer: Apple Mail (2.3445.104.11) X-Rspamd-Queue-Id: 8942876D2A X-Spamd-Bar: ++ X-Spamd-Result: default: False [2.62 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; R_SPF_ALLOW(-0.20)[+ptr:yahoo.com]; MV_CASE(0.50)[]; FREEMAIL_FROM(0.00)[yahoo.com]; RCVD_COUNT_THREE(0.00)[3]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[yahoo.com:+]; MX_GOOD(-0.01)[cached: mta6.am0.yahoodns.net]; DMARC_POLICY_ALLOW(-0.50)[yahoo.com,reject]; FROM_EQ_ENVFROM(0.00)[]; RCVD_TLS_LAST(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[yahoo.com]; ASN(0.00)[asn:36647, ipnet:98.137.64.0/21, country:US]; MID_RHS_MATCH_FROM(0.00)[]; DWL_DNSWL_NONE(0.00)[yahoo.com.dwl.dnswl.org : 127.0.5.0]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[yahoo.com:s=s2048]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; NEURAL_SPAM_SHORT(0.18)[0.175,0]; MIME_GOOD(-0.10)[text/plain]; IP_SCORE(1.59)[ip: (6.28), ipnet: 98.137.64.0/21(0.95), asn: 36647(0.76), country: US(-0.06)]; NEURAL_SPAM_MEDIUM(0.85)[0.850,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_SPAM_LONG(0.51)[0.514,0]; RCVD_IN_DNSWL_NONE(0.00)[31.68.137.98.list.dnswl.org : 127.0.5.0] X-BeenThere: freebsd-toolchain@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Maintenance of FreeBSD's integrated toolchain List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 08 Jun 2019 22:57:43 -0000 The failure is related to *sp++ in the below source code from lib/libc/gen/tls.c . extern char **environ; =20 void _init_tls(void) { #ifndef PIC Elf_Addr *sp; Elf_Auxinfo *aux, *auxp; Elf_Phdr *phdr; size_t phent, phnum; int i; void *tls; sp =3D (Elf_Addr *) environ; while (*sp++ !=3D 0) ; . . . system-clang-8 produced the following code in /sbin/init : 01812f50 <_init_tls> mflr r0 01812f54 <_init_tls+0x4> stw r0,4(r1) 01812f58 <_init_tls+0x8> stwu r1,-16(r1) 01812f5c <_init_tls+0xc> stw r31,12(r1) 01812f60 <_init_tls+0x10> mr r31,r1 01812f64 <_init_tls+0x14> lis r3,404 01812f68 <_init_tls+0x18> lwz r4,-28276(r3) #### Note: r4=3D*environ 01812f6c <_init_tls+0x1c> li r5,0 01812f70 <_init_tls+0x20> addi r3,r4,-4 01812f74 <_init_tls+0x24> lwzu r7,4(r3) #### fails here 01812f78 <_init_tls+0x28> mr r6,r5 01812f7c <_init_tls+0x2c> addi r5,r5,1 01812f80 <_init_tls+0x30> cmplwi r7,0 01812f84 <_init_tls+0x34> bne+ 01812f74 <_init_tls+0x24> . . . readelf -asW shows environ as: 2652: 000000000193918c 4 OBJECT GLOBAL DEFAULT 17 environ MAJOR CONCLUSION (so far): It appears that the values found by the sp++ are strange so *sp++ gets the SIGSEGV. The: 01812f64 <_init_tls+0x14> lis r3,404 01812f68 <_init_tls+0x18> lwz r4,-28276(r3) does match up: 0x193918c=3D=3D(404<<16)-28276 . It looks like the Elf_Addr value itself is strange when the SIGSEGV's happen. The evidence for where the failure point is was: KDB: enter p_pid 1 got signal 11 [ thread pid 1 tid 100002 ] Stopped at kdb_enter+0x74: addi r3,r0,0x0 db> bt Tracing pid 1 tid 100002 td 0x1506ae0 0xd6b7c950: at cursig+0x55c 0xd6b7ca10: at ast+0x508 0xd6b7ca40: user DSI read trap @ 0x1c000020 by 0x1812f74: srr1=3D0xd032 r1=3D0xffffde90 cr=3D0x20000000 xer=3D0 ctr=3D0 sr=3D0x40000000= frame=3D0xd6b7ca48 db> The "trap @" value can vary, such as instead being 0xfa5005af . =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)