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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5284C433EF for ; Mon, 16 May 2022 21:13:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347620AbiEPVN3 (ORCPT ); Mon, 16 May 2022 17:13:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349416AbiEPVM4 (ORCPT ); Mon, 16 May 2022 17:12:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54D7C1025 for ; Mon, 16 May 2022 14:06:22 -0700 (PDT) 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 dfw.source.kernel.org (Postfix) with ESMTPS id E15AB61507 for ; Mon, 16 May 2022 21:06:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1BB3C385AA; Mon, 16 May 2022 21:06:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1652735181; bh=Ft3I/yXXzukonb8keZt04JE4bLkRTsLc5hGPoDdn4Uo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zAjekkEBLgFVfxbiE2VjdxIw5F6h8LoiroA17MJAXyoKI72CH2w/B8BBqaxVdZ/fV Q/onCdq0E18mMzNhf2atxs14Lfrs8u7VtNX+ngILufMAl83aQy/5bZmIT/7BTgR2CF ewe38DwQI09Y1VLQ6Y9bWXWlfi2KPAYZxvwrIwu4= Date: Mon, 16 May 2022 14:06:20 -0700 From: Andrew Morton To: Maxim Zhukov Cc: chi.minghao@zte.com.cn, varad.gautam@suse.com, arnd@arndb.de, shakeelb@google.com, vasily.averin@linux.dev, manfred@colorfullife.com, dbueso@suse.de, linux-kernel@vger.kernel.org, Maxim Zhukov Subject: Re: [RFC PATCH 1/1] ipc, sem: fix backward compatibility with x86-32 kernels Message-Id: <20220516140620.85f84d560c85d01d48dae917@linux-foundation.org> In-Reply-To: <20220515200103.1408370-2-mussitantesmortem@gmail.com> References: <20220515200103.1408370-1-mussitantesmortem@gmail.com> <20220515200103.1408370-2-mussitantesmortem@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 15 May 2022 23:01:03 +0300 Maxim Zhukov wrote: > Since with commit 275f22148e87 ("ipc: rename old-style shmctl/semctl/msgctl syscalls") > we have changed behavior: > > ksys_semctl lost parse ipc version (ipc_parse_version), because the > new syscall works with IPC_64 only, but the parse function has some > side effect - it removes IPC_64 bit from `cmd`. > > Some libc forced sends IPC_64 bit in semctl syscall[1][2][3], this leads to > a bug - X86-32 kernel does not have compat headers and does not > correctly parse received command (cmd) from semctl syscall: cmd have actual > command and IPC_64 bit, thus throw EINVAL error in ksys_semctl > > This commit forcibly removes IPC_64 bit from the cmd for restore > backward compatibility. > > [1]: https://elixir.bootlin.com/uclibc-ng/v1.0.40/source/libc/misc/sysvipc/sem.c#L58 > [2]: https://elixir.bootlin.com/musl/v1.2.3/source/src/ipc/semctl.c#L48 -> https://elixir.bootlin.com/musl/v1.2.3/source/src/ipc/ipc.h#L22 > [3]: https://elixir.bootlin.com/glibc/glibc-2.35/source/sysdeps/unix/sysv/linux/semctl.c#L124 > Thanks. 275f22148e87 was three years ago. Can you suggest why it took so long for this to be discovered?