From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/13536 Path: news.gmane.org!.POSTED!not-for-mail From: Markus Wichmann Newsgroups: gmane.linux.lib.musl.general Subject: Re: aio_cancel segmentation fault for in progress write requests Date: Fri, 7 Dec 2018 21:35:32 +0100 Message-ID: <20181207203532.GA2554@voyager> References: <20181207154419.GD23599@brightrain.aerifal.cx> <20181207165217.GE23599@brightrain.aerifal.cx> <54b4d253-1660-3207-5d59-f23f1c25b2b9@adelielinux.org> <20181207182650.GF23599@brightrain.aerifal.cx> <03a5f237-87cd-5580-4148-a29fa22d3ef0@adelielinux.org> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: blaine.gmane.org 1544214841 6290 195.159.176.226 (7 Dec 2018 20:34:01 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 7 Dec 2018 20:34:01 +0000 (UTC) User-Agent: Mutt/1.10.1 (2018-07-13) To: musl@lists.openwall.com Original-X-From: musl-return-13552-gllmg-musl=m.gmane.org@lists.openwall.com Fri Dec 07 21:33:57 2018 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1gVMou-0001W6-Uu for gllmg-musl@m.gmane.org; Fri, 07 Dec 2018 21:33:57 +0100 Original-Received: (qmail 18217 invoked by uid 550); 7 Dec 2018 20:36:06 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 18199 invoked from network); 7 Dec 2018 20:36:05 -0000 Content-Disposition: inline In-Reply-To: <03a5f237-87cd-5580-4148-a29fa22d3ef0@adelielinux.org> X-Provags-ID: V03:K1:74QXLhrNkIJccXunG/ZCIfrGWkUAx67P27/7sokcSjo3NEjilwb hQb3p24O9bCQMKO4CJfena0+UOYy8Zok//FHvyQs+izideS70ovU6LejwcaCRlkUw8U23uM oy8ONO5KB7Vy+CRZZCz/FEejlZAOv//WsLme8pj6wOnO12M0k2gAR+GswqixbK6RPlT40c6 EAweFXc0bDQuWIqRo5Y5A== X-UI-Out-Filterresults: notjunk:1;V03:K0:q5lIZMyre1E=:FFNd79lDJ7cK9iCZDbkyXu RlCGUsmuYiVTpf1JqdQymWjXbc5Gsshpuk8McQadbtTb+776thAlvALLnrHnPirnMCUO9Idz/ KvvqhEY9FvxXFBL2snyeQiwSYIQKn1oO5UutUupZuj37drMG4UcADORFGyz169nCTWEf/adJV XwhhSUtlRCheUx47Hhl0x5ib67pG4xwWN0OuTutO0gIu8Uq5iP9hgkcYbvS8uftdn7ZzCPEgm ObsAvKbUymFv9BEosS0rJS4dGk6LZN5Aco60g5NrCJDsOrHLgAE3KdjHOL+1E559uUAXHTT2M 5z9V2TiwI3P6wIfCztjCXYIpJgd40d5c2DBh9qZIhGXAuPgoG6By4MGSnPunW2QlL0iVLi9U7 Npn55pdCYA/lEsyscnYReiSUe2OMjD3UB5H9ZI8VmqrKOOd0uhJ9FkwycuaFYtKkvykXNWQ6F +NwyCzeRZ/uS5q5P8Y3kU/hJlntsSwp9iJRsGxbHcic1xYAXs30sSytfizrBVMQJ+zJP7ZdyD yftBbkkXOH6yxkZ3KAy3alfSlsdC4c+tnfwXLA4lzQ8jfC80Ux1x7SrSGi4ZbkqevZDpTlhIk f4jXCf7EAfZGGCQL54Ll3LafvL0ZW8Z+mFjbZF4na+XcjXVedvxdBB9wjdfKr5dt6bXvHem91 2L5XOWrWbu7GR8TQf49idorrHfpwn82v5swUOFrxUdk9bNlg5RRNlcaRGMN4H42r0e+Ta3tg/ KmMPY2yJ/UJ7t0HyR7ay3MNSJ8zG20V2h1VnBqaN53tQAnLFi4LSGt24/J7W/I/a35fP6zKU Xref: news.gmane.org gmane.linux.lib.musl.general:13536 Archived-At: On Fri, Dec 07, 2018 at 01:13:44PM -0600, A. Wilcox wrote: > So, my best theory is that running inside a debugger (gdb, valgrind) > makes it slow enough that it no longer races. Two ideas to investigate further. 1: Produce a coredump ("ulimit -c unlimited"). That won't interfere with timing, but I have no clue if coredumps work with multithreading. 2: Might I suggest installing a SIGSEGV handler? If you have libunwind, you can create a backtrace from inside the handler. And even if not, you can at least print the exception PC, which would help a ton already. Only, don't return from that handler. Either _exit(), or better yet, restore the default handler, then kill yourself with SIGSEGV. Ciao, Markus