From owner-freebsd-stable@freebsd.org Sat Aug 12 20:38:05 2017 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 120C7DC833E for ; Sat, 12 Aug 2017 20:38:05 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F410370844 for ; Sat, 12 Aug 2017 20:38:04 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from bugs.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id v7CKc4dk086605 for ; Sat, 12 Aug 2017 20:38:04 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-stable@FreeBSD.org Subject: [Bug 213903] Kernel crashes from turnstile_broadcast (/usr/src/sys/kern/subr_turnstile.c:837) Date: Sat, 12 Aug 2017 20:38:05 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: crash, needs-qa, patch X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: markmi@dsl-only.net X-Bugzilla-Status: In Progress X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: mjg@FreeBSD.org X-Bugzilla-Flags: mfc-stable10+ mfc-stable11+ X-Bugzilla-Changed-Fields: cc Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Aug 2017 20:38:05 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D213903 Mark Millard changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |markmi@dsl-only.net --- Comment #55 from Mark Millard --- (In reply to muxx.dev from comment #54)\ Looks to me like ts=3D=3D0x0 was the starting value given to turnstile_broadcast in each backtrace listed in this buzilla bug (213903), for example: (kgdb) list *0xffffffff80b3a89c 0xffffffff80b3a89c is in turnstile_broadcast (/usr/src/sys/kern/subr_turnstile.c:837). 832 833 /* 834 * Transfer the blocked list to the pending list. 835 */ 836 mtx_lock_spin(&td_contested_lock); 837 TAILQ_CONCAT(&ts->ts_pending, &ts->ts_blocked[queue], td_lockq); 838 mtx_unlock_spin(&td_contested_lock); 839 840 /* 841 * Give a turnstile to each thread. The last thread gets Current language: auto; currently minimal (kgdb) backtrace . . . #8 0xffffffff80b3a89c in turnstile_broadcast (ts=3D0x0, queue=3D1) at /usr/src/sys/kern/subr_turnstile.c:837 #9 0xffffffff80ad48cf in __rw_wunlock_hard (c=3D0xfffff800437de858, tid=3D= , file=3D, line=3D)= at /usr/src/sys/kern/kern_rwlock.c:1027 . . . Note that ts=3D=3D0x0 would be a problem for: TAILQ_CONCAT(&ts->ts_pending, &ts->ts_blocked[queue], td_lockq); So I wonder if __rw_wunlock_hard is providing a bad ts value. If yes: the problem then occurs before the turnstile_broadcast call is made. --=20 You are receiving this mail because: You are on the CC list for the bug.=