From owner-freebsd-hackers@freebsd.org Fri Apr 16 23:51:15 2021 Return-Path: Delivered-To: freebsd-hackers@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D30AD5E5874 for ; Fri, 16 Apr 2021 23:51:15 +0000 (UTC) (envelope-from freebsd-hackers@m.gmane-mx.org) Received: from ciao.gmane.io (ciao.gmane.io [116.202.254.214]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4FMXzQ2cYgz3GwP for ; Fri, 16 Apr 2021 23:51:13 +0000 (UTC) (envelope-from freebsd-hackers@m.gmane-mx.org) Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lXYEs-00037N-Hd for freebsd-hackers@freebsd.org; Sat, 17 Apr 2021 01:51:06 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-hackers@freebsd.org From: Johannes Totz Subject: Debugging signal 11 Date: Sat, 17 Apr 2021 00:51:01 +0100 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 X-Mozilla-News-Host: news://news.gmame.org:119 Content-Language: en-GB X-Rspamd-Queue-Id: 4FMXzQ2cYgz3GwP X-Spamd-Bar: ++++ Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=jo-t.de (policy=none); spf=pass (mx1.freebsd.org: domain of freebsd-hackers@m.gmane-mx.org designates 116.202.254.214 as permitted sender) smtp.mailfrom=freebsd-hackers@m.gmane-mx.org X-Spamd-Result: default: False [4.10 / 15.00]; RCVD_TLS_LAST(0.00)[]; ARC_NA(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; RBL_SENDERSCORE_FAIL(0.00)[116.202.254.214:server fail]; FROM_HAS_DN(0.00)[]; RBL_DBL_DONT_QUERY_IPS(0.00)[116.202.254.214:from]; MV_CASE(0.50)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_SPAM_MEDIUM(1.00)[1.000]; RCPT_COUNT_ONE(0.00)[1]; SPAMHAUS_ZRD(0.00)[116.202.254.214:from:127.0.2.255]; DMARC_POLICY_SOFTFAIL(0.10)[jo-t.de : SPF not aligned (relaxed), No valid DKIM,none]; R_SPF_ALLOW(-0.20)[+mx]; NEURAL_SPAM_SHORT(1.00)[0.998]; FORGED_SENDER(0.30)[johannes@jo-t.de,freebsd-hackers@m.gmane-mx.org]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:24940, ipnet:116.202.0.0/16, country:DE]; FORGED_MUA_THUNDERBIRD_MSGID_UNKNOWN(2.50)[]; FROM_NEQ_ENVFROM(0.00)[johannes@jo-t.de,freebsd-hackers@m.gmane-mx.org]; MAILMAN_DEST(0.00)[freebsd-hackers] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Technical discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Apr 2021 23:51:15 -0000 Hi there, My init(8) is crashing with a signal 11. I've added a breakpoint() in kern_sig.c: static int issignal(struct thread *td) { // [snip] case (intptr_t)SIG_DFL: /* * Don't take default actions on system processes. */ if (p->p_pid <= 1) { #ifdef DIAGNOSTIC /* * Are you sure you want to ignore SIGSEGV * in init? XXX */ printf("Process (pid %lu) got signal %d\n", (u_long)p->p_pid, sig); breakpoint(); // added by me #endif break; /* == ignore */ } // [snip] } That breaks to DDB where I can call dump. So far so good. But how do I get back to the stack(trace) and instruction that caused the segv? Either in DDB or KGDB? Thanks, Johannes