From patchwork Fri Jun 19 14:32:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 223628 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 C31EDC433E0 for ; Fri, 19 Jun 2020 16:53:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A04212078D for ; Fri, 19 Jun 2020 16:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592585613; bh=/YRsKm+UuUQSjVNhO4o+amEOfE2Aw0EN2Skl2Q46c+Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=C7L/HtjQO2cthwMVVMLDhWpp+Qv17jyQXk3bJ68m/TNchLu+a72JorzbbTItkKlsm hKnDg84l3RPnAIGIvmJo4+1R3bjiGuSX5CwFHyXRh5z9892yULSa+mHS1ByXixGyOV 7S2WmPJmo7qOSb4R15j0FnFBmjMrHujDv2Lj1zCw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387690AbgFSOhT (ORCPT ); Fri, 19 Jun 2020 10:37:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:53958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387638AbgFSOhK (ORCPT ); Fri, 19 Jun 2020 10:37:10 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 BC13920CC7; Fri, 19 Jun 2020 14:37:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592577430; bh=/YRsKm+UuUQSjVNhO4o+amEOfE2Aw0EN2Skl2Q46c+Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fTFsYguMeFmMkV9HPkqOa3mj2vCldpIqzfcoFWCCWDF8O5e+PH1TC2jMyz24lV5Ng SD9d71GDjfdY2Xuw+YTj2LhLQyfxkcpFfU4ELr+NSEYv0lMvR1aGWs9his26tEr8KU DjdAulv8CErDhopnaPPCoGZc/96WdUifSAeL+Lyg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Douglas Anderson , Daniel Thompson , Sasha Levin Subject: [PATCH 4.4 048/101] kgdb: Prevent infinite recursive entries to the debugger Date: Fri, 19 Jun 2020 16:32:37 +0200 Message-Id: <20200619141616.595392541@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141614.001544111@linuxfoundation.org> References: <20200619141614.001544111@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Douglas Anderson [ Upstream commit 3ca676e4ca60d1834bb77535dafe24169cadacef ] If we detect that we recursively entered the debugger we should hack our I/O ops to NULL so that the panic() in the next line won't actually cause another recursion into the debugger. The first line of kgdb_panic() will check this and return. Signed-off-by: Douglas Anderson Reviewed-by: Daniel Thompson Link: https://lore.kernel.org/r/20200507130644.v4.6.I89de39f68736c9de610e6f241e68d8dbc44bc266@changeid Signed-off-by: Daniel Thompson Signed-off-by: Sasha Levin --- kernel/debug/debug_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 79517e5549f1..9c939c6bf21c 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -443,6 +443,7 @@ static int kgdb_reenter_check(struct kgdb_state *ks) if (exception_level > 1) { dump_stack(); + kgdb_io_module_registered = false; panic("Recursive entry to debugger"); }