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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 79010C4332F for ; Mon, 12 Dec 2022 07:32:01 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4NVtcH5vVhz3bZx for ; Mon, 12 Dec 2022 18:31:59 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Yc0SnRZO; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=2604:1380:40e1:4800::1; helo=sin.source.kernel.org; envelope-from=bugzilla-daemon@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=Yc0SnRZO; dkim-atps=neutral Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4NVtbC4pCwz3bZh for ; Mon, 12 Dec 2022 18:31:03 +1100 (AEDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 0A70FCE0E03 for ; Mon, 12 Dec 2022 07:31:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPS id 46EA7C433EF for ; Mon, 12 Dec 2022 07:30:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670830259; bh=2NDast8UQOlkNy6yCucanqKI0+EsHyBhu+k9qFjXEKY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=Yc0SnRZOEq7F1f+149w1R6CWaMkyT/BnlsSX2FGqUC2jrrGNWNOlg/UNRccEh4Wo8 nvPXhTGIi7OtLWj7xxzuVmkBpEVWKTmrfh2bge1TyKOq+KXf2m1zY6QcZb5wIsqH3u /3FAv4at6aqHHU0cPcuFRPbqSBfp5UbpYdqEdFz0w5ugithEBQYGqyE/ZAG3nOxC+Z 4lCVGiDgvtP697dDWeDj9HCcGV3gXRV9QXR9cqg9z4wojnzzHC2CF/flM04A0rKb3/ Apn1munSk2Jog1H7LtSO6jNdv9u8WBjdmA4ruLC3/GQHu/sNBncvIfbbMS7E79vCVN /vXrtE8WDcZdA== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 31269C43142; Mon, 12 Dec 2022 07:30:59 +0000 (UTC) From: bugzilla-daemon@kernel.org To: linuxppc-dev@lists.ozlabs.org Subject: [Bug 214913] [xfstests generic/051] BUG: Kernel NULL pointer dereference on read at 0x00000108 NIP [c0000000000372e4] tm_cgpr_active+0x14/0x40 Date: Mon, 12 Dec 2022 07:30:59 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo platform_ppc-64@kernel-bugs.osdl.org X-Bugzilla-Product: Platform Specific/Hardware X-Bugzilla-Component: PPC-64 X-Bugzilla-Version: 2.5 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: christophe.leroy@csgroup.eu X-Bugzilla-Status: NEEDINFO X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: platform_ppc-64@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" https://bugzilla.kernel.org/show_bug.cgi?id=3D214913 --- Comment #11 from Christophe Leroy (christophe.leroy@csgroup.eu) --- Le 12/12/2022 =C3=A0 04:52, Nicholas Piggin a =C3=A9crit=C2=A0: > On Sun Dec 11, 2022 at 11:19 PM AEST, wrote: >> https://bugzilla.kernel.org/show_bug.cgi?id=3D214913 >> >> --- Comment #7 from Zorro Lang (zlang@redhat.com) --- >> (In reply to Michael Ellerman from comment #5) >>> Sorry I don't have any idea which commit could have fixed this. >>> >>> The process that crashed was "fsstress", do you know if it uses io_urin= g? >> >> Yes, fsstress has io_uring read/write operations. And from the kernel >> .config >> file(as attachment), the CONFIG_IO_URING=3Dy >=20 > The task being dumped seems like it's lost its task->thread.regs. The > NULL pointer is here: >=20 > int tm_cgpr_active(struct task_struct *target, const struct user_regset > *regset) > { > if (!cpu_has_feature(CPU_FTR_TM)) > return -ENODEV; >=20 > if (!MSR_TM_ACTIVE(target->thread.regs->msr)) > return 0; >=20 > return regset->n; > } >=20 > On that regs->msr deref. r9 contains the regs pointer. >=20 > The kernel attempt to read user page - exploit attempt? message is > I think a red herring it's coming up because of the NULL deref I > think (I thought we fixed that). >=20 No we didn't fix that, my patch was rejected see=20 https://patchwork.ozlabs.org/project/linuxppc-dev/patch/8b865b93d25c15c8e6d= 41e71c368bfc28da4489d.1606816701.git.christophe.leroy@csgroup.eu/ The reason for the rejection was: The first page can be mapped if mmap_min_addr is 0. Blocking all faults to the first page would potentially break any program that does that. Also if there is something mapped at 0 it's a good chance it is an exploit attempt :) Christophe --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=