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=-14.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 2E945C433DB for ; Wed, 23 Dec 2020 09:49:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E38A1222B3 for ; Wed, 23 Dec 2020 09:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728089AbgLWJtq (ORCPT ); Wed, 23 Dec 2020 04:49:46 -0500 Received: from mout.gmx.net ([212.227.17.22]:60513 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726022AbgLWJtp (ORCPT ); Wed, 23 Dec 2020 04:49:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1608716891; bh=65nC/HIa2Iw+m1jZNyib0HWtljb/LeXqdwbAk2EgPYI=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=bpnWEIf+jRO3wV+4x01rnV/5YyOqpG9k2jAGURrJRWiBdc9vc0f04g/aRIAYSdBk0 +kNf7L7jl53yyDXqpv2Dg1ag4cOyfodr5OGVH57QcV3/+cB5kgl/nAtWewsOGauJUg WudPC6ozCpCBcXd9tYIAtaj/hAiTGq6aQh/4mtYA= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [192.168.20.60] ([92.116.156.206]) by mail.gmx.com (mrgmx105 [212.227.17.168]) with ESMTPSA (Nemesis) id 1M3UZG-1krSWG3RVi-000Zpk; Wed, 23 Dec 2020 10:48:10 +0100 Subject: Re: [PATCH] proc/wchan: Use printk format instead of lookup_symbol_name() To: Andrew Morton Cc: Alexey Dobriyan , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20201217165413.GA1959@ls3530.fritz.box> <20201222181807.360cd9458d50b625608b8b44@linux-foundation.org> From: Helge Deller Autocrypt: addr=deller@gmx.de; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20201222181807.360cd9458d50b625608b8b44@linux-foundation.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:gRmuymGPB2LiNQ4rNhvvXmoz1yazFT4wiKbtNc6Z8rEG6IT3DCU Hv7Q4ZEx1rSIJuvDO2hX7VM49rGf2C82Ja2Z4klmHQShQwHwZQ9BTPfGclXdgeiyGQ/B8Vo hTJhy9/qAVUUQcqzqoFgBv1ywY9F2IvMWGm7HOYYwBHYS2lRKJVOWn5OScwGBrTfQV9Uol+ 5LXHQDblC9HEOZuY6866w== X-UI-Out-Filterresults: notjunk:1;V03:K0:sUNSr/yqII8=:OxBfkv1UwqxWrNFMeT/nhL lHTmDd9qfp0OCf4Eh8AGP9u9cM4nmpIIffe4wYvpyVJMAaAFAbvoWEMy52RqU3UNK7im6cM32 XNbwIrLAyAhTK30TDidOwIZP0st2uKILaDTEzk4+f0R4I/3NMXhkPHFiDiUgwBjbKiJjBGKMM 2SyRC/KmUYfpCUZ2Mv5xqY1wyP9qGJueY4iLDuk+0R1xdkcULvpS5k2rzZ5dOvl3zbIbHdMhQ Ynju3L2DysEbIm2A85wV9WqmRXtfJO0SewhXVRw31BHZI1VAGDGsQk+HgFpJW2HrunKF3i2L2 mSJ5pSxRUPvP1lF0rQeTJPhpCJyJYFdBQveVWdNoqAJ2C+IDv306WODPeJbBU5cqN19ZktlTC VuOOxzfRy6rvvoGgGKiJKNSnbWe3xfNKcDymEhvTrqrRf6koT6qpgjg/ByYSaj+o7y30MuzSV xrQRNGeAHOt5qTQOS3elicpewBZwbMsZX7IzM7SFQ0F5jQCfzc8QCL/B+PO2ogZRsBhISC7Qi Cv7MCLi460xJAJGvvR2YClDOD3IaKhHP4ePJBqWI3tRGILze5pErK7edBuqZfOR0rbZQBN+SK LOr2vDB9XTlpfigftB/1KBDiflhdkoe66YZ8MTmTjNvNdEcqG45iCmCe54AP2UbhvklyTvzS+ 4npuiuBYYGPU1o4nLgI94USX0UJfsHx0VTzbdi9lR9K1OXxlAmF9E7mEuqHyGxPxuTVNO6/I3 0Bvrx+SQanLLbgXja+4BMEt0U0fI8yWfNVuuzxqse0KQx2AGCBbL9a7pH4cMiQtoKnOybDEjJ Fy2pQAoHALrHle6PyBl0osoYTiOkhT+k0kjyBOkdRGmu/MOfCZD8KoRpl2x6irvB5I5ixfhnZ HMGFrKwQMvsDVaJombgA== Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 12/23/20 3:18 AM, Andrew Morton wrote: > On Thu, 17 Dec 2020 17:54:13 +0100 Helge Deller wrote: > >> To resolve the symbol fuction name for wchan, use the printk format >> specifier %ps instead of manually looking up the symbol function name >> via lookup_symbol_name(). >> >> Signed-off-by: Helge Deller >> > > Please don't forget the "^---$" to separate the changelog from the > diff. Ok. > >> #include >> @@ -386,19 +385,17 @@ static int proc_pid_wchan(struct seq_file *m, str= uct pid_namespace *ns, >> struct pid *pid, struct task_struct *task) >> { >> unsigned long wchan; >> - char symname[KSYM_NAME_LEN]; >> >> - if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) >> - goto print0; >> + if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) >> + wchan =3D get_wchan(task); >> + else >> + wchan =3D 0; >> >> - wchan =3D get_wchan(task); >> - if (wchan && !lookup_symbol_name(wchan, symname)) { >> - seq_puts(m, symname); >> - return 0; >> - } >> + if (wchan) >> + seq_printf(m, "%ps", (void *) wchan); >> + else >> + seq_putc(m, '0'); >> >> -print0: >> - seq_putc(m, '0'); >> return 0; >> } > > We can simplify this further? > > static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns, > struct pid *pid, struct task_struct *task) > { > if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) > seq_printf(m, "%ps", (void *)get_wchan(task)); > else > seq_putc(m, '0'); > > return 0; > } > > > --- a/fs/proc/base.c~proc-wchan-use-printk-format-instead-of-lookup_symb= ol_name-fix > +++ a/fs/proc/base.c > @@ -384,15 +384,8 @@ static const struct file_operations proc > static int proc_pid_wchan(struct seq_file *m, struct pid_namespace *ns, > struct pid *pid, struct task_struct *task) > { > - unsigned long wchan; > - > if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) > - wchan =3D get_wchan(task); > - else > - wchan =3D 0; > - > - if (wchan) > - seq_printf(m, "%ps", (void *) wchan); > + seq_printf(m, "%ps", (void *)get_wchan(task)); > else > seq_putc(m, '0'); get_wchan() does return NULL sometimes, in which case with your change now "0x0" instead of "0" gets printed. If that's acceptable, then your patch is Ok. Helge