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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 206E6C432BE for ; Mon, 30 Aug 2021 19:39:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00EB860F9E for ; Mon, 30 Aug 2021 19:39:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233573AbhH3Tkv (ORCPT ); Mon, 30 Aug 2021 15:40:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230114AbhH3Tku (ORCPT ); Mon, 30 Aug 2021 15:40:50 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57646C061575 for ; Mon, 30 Aug 2021 12:39:56 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1630352395; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=us4dmtVLXOhNn9SThCdMpJkgWctajJqeNbWFhIv2Wjk=; b=w1DGI5f3GsQ5XJ4Hm8f9cflw12YQjjmpsvX0ed2lhb0M7tTFoEyH2/2Hs9sBdRtbbmhpcB iDsdIjacnqAFk/myKXsTWj+/pe5Q1dZKZMG2b/o5wRrK3sBI840xaL7cuaGwEiJgnY9hLU R8qRzE2U0utTpkAxQYQivlc7ShFFK5H35iOEuOnpJ6cafIO1S7CiUMKnuJqDbBersk10U4 09Mbf8yJ+se23hb61zmwMCTKPMWoQtpO+4HyTUsWlXpNREgxpnHLURRdUBq4EnikMFrBUq 6VnpPIf8DdWK1/0WbT+xa9vas1mzTEQWTN6V8+TaWAWlOpUiREzLmNoo+RM50w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1630352395; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=us4dmtVLXOhNn9SThCdMpJkgWctajJqeNbWFhIv2Wjk=; b=9WN9YKp4fJ5C8PXIMkn5twBtFlDcUVE7xXBV3yA81osDU+vL+ir3Ds1nObgWp3Ur4duKLP 7BSzMfnmIC9mifCQ== To: paulmck@kernel.org Cc: syzbot , bp@alien8.de, dwmw@amazon.co.uk, hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@redhat.com, syzkaller-bugs@googlegroups.com, x86@kernel.org Subject: Re: [syzbot] WARNING in rcu_core In-Reply-To: <20210830170647.GT4156@paulmck-ThinkPad-P17-Gen-1> References: <000000000000d4ba6405cac3b065@google.com> <87eeabgq84.ffs@tglx> <20210830170647.GT4156@paulmck-ThinkPad-P17-Gen-1> Date: Mon, 30 Aug 2021 21:39:54 +0200 Message-ID: <875yvmhgc5.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 30 2021 at 10:06, Paul E. McKenney wrote: > On Mon, Aug 30, 2021 at 12:51:39PM +0200, Thomas Gleixner wrote: > > This looks like a use-after-free in a structure that unions the rcu_head > structure with something else. > > Would adding a mem_dump_obj() somewhere in the debug-object code be > helpful? At least for the case where the object is not available in the debug objects tracking. > (Or propagate a return value out, similar to that of > debug_object_activate()?) That might be useful for some callers as well. Thanks, tglx