From owner-freebsd-net Tue Jul 4 11:29:38 2000 Delivered-To: freebsd-net@freebsd.org Received: from khavrinen.lcs.mit.edu (khavrinen.lcs.mit.edu [18.24.4.193]) by hub.freebsd.org (Postfix) with ESMTP id 85A2D37B59B for ; Tue, 4 Jul 2000 11:29:34 -0700 (PDT) (envelope-from wollman@khavrinen.lcs.mit.edu) Received: (from wollman@localhost) by khavrinen.lcs.mit.edu (8.9.3/8.9.3) id OAA22401; Tue, 4 Jul 2000 14:29:20 -0400 (EDT) (envelope-from wollman) Date: Tue, 4 Jul 2000 14:29:20 -0400 (EDT) From: Garrett Wollman Message-Id: <200007041829.OAA22401@khavrinen.lcs.mit.edu> To: Kevin Bracey Cc: freebsd-net@FreeBSD.ORG Subject: Race condition in TCP connection drops? In-Reply-To: <282ed4d849%kbracey@kbracey.cam.pace.co.uk> References: <282ed4d849%kbracey@kbracey.cam.pace.co.uk> Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org < said: > This is totally reliable on our system, because the psignal mechanism is > synchronous. Are there interlocks to prevent this happening on FreeBSD, or is > it a race condition? On all BSD systems since time immemorial (and probably Bell Labs Unix before that), signal delivery is asynchronous, and the kernel is non-preemptible, so this is not possible. (There are no explicit interlocks /per se/; it's merely the consequence of a design choice made many years ago.) -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message