From owner-freebsd-bugs@freebsd.org Mon Aug 27 16:11:39 2018 Return-Path: Delivered-To: freebsd-bugs@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 D209A108F243 for ; Mon, 27 Aug 2018 16:11:39 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 6EE367783D for ; Mon, 27 Aug 2018 16:11:39 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id 34886108F242; Mon, 27 Aug 2018 16:11:39 +0000 (UTC) Delivered-To: bugs@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 2340F108F241 for ; Mon, 27 Aug 2018 16:11:39 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id B89E077839 for ; Mon, 27 Aug 2018 16:11:38 +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 mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id 1310F1655C for ; Mon, 27 Aug 2018 16:11:38 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id w7RGBb2o043101 for ; Mon, 27 Aug 2018 16:11:37 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id w7RGBbj7043100 for bugs@FreeBSD.org; Mon, 27 Aug 2018 16:11:37 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 230856] tail -f fails unexpectedly with EINTR if truss is run against it. Date: Mon, 27 Aug 2018 16:11:38 +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: jhb@FreeBSD.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: 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: 2.1.27 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Aug 2018 16:11:40 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D230856 --- Comment #3 from John Baldwin --- This is a known longstanding issue with ptrace() and not trivially fixable.= =20 (It's also documented in truss's manpage I think, or perhaps only in gcore's manpage.) I have been trying to work on a possible solution for several months, but it won't be ready any time soon. (In particular, the issue is = that ptrace() doesn't pass the signal to the debugger which then discards it unt= il after it has awakened the sleeping thread and forced it out to the user/ker= nel boundary. The fix I'm working on aims to keep the thread asleep while lett= ing the debugger intercept the signal and only interrupting the thread if the debugger passes the signal. The current WIP can be found here, but it's not really tested at all yet and I think it still panics when trying to use ptrace(): https://github.com/freebsd/freebsd/compare/master...bsdjhb:spurious_EINTR ) --=20 You are receiving this mail because: You are the assignee for the bug.=