From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18686 invoked by alias); 13 Jan 2015 14:39:44 -0000 Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org Received: (qmail 18657 invoked by uid 89); 13 Jan 2015 14:39:42 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.7 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.3.2 X-HELO: rock.gnat.com Received: from rock.gnat.com (HELO rock.gnat.com) (205.232.38.15) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Tue, 13 Jan 2015 14:39:41 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id 27FE4116431; Tue, 13 Jan 2015 09:39:40 -0500 (EST) Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id ytVjc38bv-3T; Tue, 13 Jan 2015 09:39:40 -0500 (EST) Received: from joel.gnat.com (localhost.localdomain [127.0.0.1]) by rock.gnat.com (Postfix) with ESMTP id AE95F116291; Tue, 13 Jan 2015 09:39:39 -0500 (EST) Received: by joel.gnat.com (Postfix, from userid 1000) id 205B148E8B; Tue, 13 Jan 2015 18:39:35 +0400 (RET) Date: Tue, 13 Jan 2015 14:39:00 -0000 From: Joel Brobecker To: Jan Kiszka Cc: gdb@sourceware.org, Pedro Alves Subject: Re: python-injected silent breakpoints broken since 1a853c52 Message-ID: <20150113143935.GI8139@adacore.com> References: <54B52A1B.1090409@siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54B52A1B.1090409@siemens.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-SW-Source: 2015-01/txt/msg00019.txt.bz2 Jan, > I've stumbled over a regression of gdb since commit 1a853c52 (make > "permanent breakpoints" per location and disableable). My gdb python > scripts [1] that load Linux kernel module symbols as the target loads > the modules now fail. > > The involved command is lx-symbols [2]. It installs a silent breakpoint > on a kernel function that is called when a module is loaded. Before > 1a853c52, the python callback was normally invoked and the target > continued to run. Since af48d08f (1a853c52 is not testable), the int3 > instruction (I'm testing with x86) is left in the target, and garbage > instructions are executed, causing a kernel oops. The breakpoint is > apparently not properly skipped (remove, single-step, re-insert) when > resuming the target on return from LoadModuleBreakpoint.stop(). > > I can provide more details on how to set up a reproduction case but I > would only gather them when desired as that is not straightforward. > > Jan > > [1] https://lkml.org/lkml/2014/11/20/531 > [2] > http://git.kiszka.org/?p=linux.git;a=blob;f=scripts/gdb/linux/symbols.py;h=bf05e451c58666add299061046bf1ceb9e82f4ef;hb=d92098e7cf60d31ccd025e56d20c23917ccd0819 Thanks for the report! Can you please open a PR at the following URL? https://sourceware.org/bugzilla/ There is a chance that we might consider this regression as release blocking for GDB 7.9 (planned for the near future), and having PR makes things a lot easier to track. Thank you! -- Joel