From owner-freebsd-bugs@freebsd.org Tue May 9 07:40:33 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 BD948D65145 for ; Tue, 9 May 2017 07:40:33 +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 1BBEA1365 for ; Tue, 9 May 2017 07:40:33 +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 v497eWOa022756 for ; Tue, 9 May 2017 07:40:32 GMT (envelope-from bugzilla-noreply@freebsd.org) From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 219159] sendmsg hangs (or EWOULDBLOCK) forever with ancillary data. Date: Tue, 09 May 2017 07:40:33 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 10.3-STABLE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: parakleta@darkreality.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: bug_id short_desc product version rep_platform op_sys bug_status bug_severity priority component assigned_to reporter Message-ID: 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: Tue, 09 May 2017 07:40:33 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D219159 Bug ID: 219159 Summary: sendmsg hangs (or EWOULDBLOCK) forever with ancillary data. Product: Base System Version: 10.3-STABLE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: parakleta@darkreality.org When sending a message over a SOCK_DGRAM that has control data `sosend_generic()` in `sys/kern/uipc_socket.c` checks `if ((atomic && resid= > so->so_snd.sb_hiwat) ...` to return `ESMSGSIZE` but then next checks `if (s= pace < resid + clen && (atomic || ...` and either returns `EWOULDBLOCK` or waits= in `sbwait()` and then restarts. `space` is calculated from `sbspace(&so->so_snd)` which is calculated to be= the minimum of `sb_hiwat - sb_cc` and another value, and so strictly less or eq= ual to `so->so_snd.sb_hiwat`. This means then that if it is the case that `resid <=3D so->so_snd.sb_hiwat= ` but `resid + clen > so->so_snd.sb_hiwat` the code will always pass the first te= st and always fail the second and so will loop forever via the `goto restart` instruction. I believe the it should be the case that `if ((atomic && resid + clen > so->so_snd.sb_hiwat) ...` the error `ESMSGSIZE` will be returned. This may be related to 181092. --=20 You are receiving this mail because: You are the assignee for the bug.=