From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF234C2BB85 for ; Thu, 16 Apr 2020 15:31:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC3DC21D91 for ; Thu, 16 Apr 2020 15:31:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587051095; bh=pKr2ODiezIbXVsIZUlYbDhELk4vhbLO4dwd5JanhVDs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=KMDmA6Zgmhr7gLF5bQX3N4flqjkuGXNA01omfr4ePSFEJQL+muomsiL44osqvevNN wKzJZcCakBh7PNlGqQTLNA+/JMxVudabUSNq5LgGjkoTPLaDum1MAf5VRpSimNoEve XleoLNTpcoRptpw4uRu1NGZB0qobMMZXwlyc6Q5E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2505882AbgDPPbf (ORCPT ); Thu, 16 Apr 2020 11:31:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:56116 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392171AbgDPNm4 (ORCPT ); Thu, 16 Apr 2020 09:42:56 -0400 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5779720732; Thu, 16 Apr 2020 13:42:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044576; bh=pKr2ODiezIbXVsIZUlYbDhELk4vhbLO4dwd5JanhVDs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=DYDoeT+4hlWnZScNJWKzbPVJP6AmaxiEBcN9QaCMwpYR+ioBzx5PL3FhzIHC2+c/+ RtXULmJ+QUoHFlldeF7OO8+NpY0b6xRd4MEh28kb8NOorpCxOltXVb4oSb79+AIqvn UMDWYBszSdyr4a5FPV5Dcb7rjUAOmOj9YorEfYTo= Date: Thu, 16 Apr 2020 22:42:50 +0900 From: Masami Hiramatsu To: Jiri Olsa Cc: Jiri Olsa , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Peter Zijlstra , lkml , "bibo,mao" , "Ziqian SUN (Zamir)" , stable@vger.kernel.org Subject: Re: [PATCH] kretprobe: Prevent triggering kretprobe from within kprobe_flush_task Message-Id: <20200416224250.7a53fb581e50aa32df75a0cf@kernel.org> In-Reply-To: <20200416091320.GA322899@krava> References: <20200408164641.3299633-1-jolsa@kernel.org> <20200409234101.8814f3cbead69337ac5a33fa@kernel.org> <20200409184451.GG3309111@krava> <20200409201336.GH3309111@krava> <20200410093159.0d7000a08fd76c2eaf1398f8@kernel.org> <20200414160338.GE208694@krava> <20200415090507.GG208694@krava> <20200416105506.904b7847a1b621b75463076d@kernel.org> <20200416091320.GA322899@krava> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jiri, On Thu, 16 Apr 2020 11:13:20 +0200 Jiri Olsa wrote: > On Thu, Apr 16, 2020 at 10:55:06AM +0900, Masami Hiramatsu wrote: > > SNIP > > > > trampoline_handler > > > kretprobe_hash_lock(current, &head, &flags); <--- deadlock > > > > > > Adding kprobe_busy_begin/end helpers that mark code with fake > > > probe installed to prevent triggering of another kprobe within > > > this code. > > > > > > Using these helpers in kprobe_flush_task, so the probe recursion > > > protection check is hit and the probe is never set to prevent > > > above lockup. > > > > > > Reported-by: "Ziqian SUN (Zamir)" > > > Signed-off-by: Jiri Olsa > > > > Thanks Jiri and Ziqian! > > > > Looks good to me. > > > > Acked-by: Masami Hiramatsu > > > > BTW, this is a kind of bugfix. So should it add a Fixes tag? > > > > Fixes: ef53d9c5e4da ('kprobes: improve kretprobe scalability with hashed locking') > > Cc: stable@vger.kernel.org > > ah right, do you want me to repost with those? Yeah, if you don't mind. Thank you, > > thanks, > jirka > -- Masami Hiramatsu