From owner-freebsd-bugs@freebsd.org Wed Jan 4 16:11:27 2017 Return-Path: Delivered-To: freebsd-bugs@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 C5C56C9E9DE for ; Wed, 4 Jan 2017 16:11:27 +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 B56B21AD2 for ; Wed, 4 Jan 2017 16:11:27 +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 v04GBR86042154 for ; Wed, 4 Jan 2017 16:11:27 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 215715] cond_test:cond_timedwait_race crashes with SIGSEGV periodically when calling binuptime Date: Wed, 04 Jan 2017 16:11:27 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: bin X-Bugzilla-Version: CURRENT X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: commit-hook@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: freebsd-bugs@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: 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-bugs@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Jan 2017 16:11:27 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D215715 --- Comment #7 from commit-hook@freebsd.org --- A commit references this bug: Author: kib Date: Wed Jan 4 16:10:52 UTC 2017 New revision: 311287 URL: https://svnweb.freebsd.org/changeset/base/311287 Log: __vdso_gettc(): be extra careful with /dev/hpet mappings, never unmap the mapping which might be accessed by other threads. If a pointer to the /dev/hpet register page mapping was stored into the hpet_dev_map, other threads might access the page at any time. Never unmap it, instead, keep track of mappings for all hpet units in smal array. Store pointer to the newly mapped registers page using CAS, to detect parallel mappings. It appeared relatively easy to demonstrate the problem by arranging two threads which perform gettimeofday(2) concurently, first time in the process address space, when HPET is used for timecounter. PR: 215715 Sponsored by: The FreeBSD Foundation MFC after: 1 week Changes: head/lib/libc/x86/sys/__vdso_gettc.c --=20 You are receiving this mail because: You are the assignee for the bug.=