From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-97.freemail.mail.aliyun.com (out30-97.freemail.mail.aliyun.com [115.124.30.97]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53CD210E9 for ; Fri, 11 Jul 2025 02:48:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.97 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752202122; cv=none; b=A9rAm8g/cK62yxMdUwVSuta6/8kxZOa1hGQf+XUOVg7ddqMaopnmYJqjMIr6H08CFcIv5eClGqnlKFnwp1s3vXVC9+zCXkbhsfipw5bq1v27Cq7In3mLO87SAKF8P7x/+KsLBmLWATNx3gwLRRdpX7QqqANEOp1nI0AAN7vObFY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752202122; c=relaxed/simple; bh=jP/J7vWHv7N+brwiaopmYpmF9BfJIn1E1i+4cetS7Rs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Xkcdk+trOOG3tHlHcxbVqBpJ+F8tGR/J3vIRqspf9oHeeco3h3wYCIb0zNWze5/7HLRmYiJ4MSWpUPeaomxVGBMxGTH75bw3A4EKVOVBYa6qes8WBT3j4AI47gPT90/p/sIvXLePnBqyvp3FlSx7z3RPbInqThN+PUg8TGQThQc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=uy6x9FWA; arc=none smtp.client-ip=115.124.30.97 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="uy6x9FWA" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1752202110; h=Date:From:To:Subject:Message-ID:MIME-Version:Content-Type; bh=UCCNYztx9T1d42FdTHtF/Z61Cuws050+HHs6h4WWS/0=; b=uy6x9FWARLbKqyFwVw/g8B2E0sD6gJQKyKF1fK150r2bAS77ju/R5tzv4ntkV730JXgy1ojYfovFJIKXQJjnUoJAjipih1OflfgKVA5JgCDb0pcTyc/DRUbCWnXIv5/bcpKGWYy5biv+U3WQPv4YyNWvu7NVnfimzCukw7JsjKQ= Received: from localhost(mailfrom:feng.tang@linux.alibaba.com fp:SMTPD_---0WifCw-._1752202109 cluster:ay36) by smtp.aliyun-inc.com; Fri, 11 Jul 2025 10:48:30 +0800 Date: Fri, 11 Jul 2025 10:48:29 +0800 From: Feng Tang To: Nathan Chancellor Cc: Andrew Morton , Andy Shevchenko , linux-kernel@vger.kernel.org, Sergey Senozhatsky , Petr Mladek Subject: Re: [PATCH v1 1/1] panic: Fix compilation error (`make W=1`) Message-ID: References: <20250710094816.771656-1-andriy.shevchenko@linux.intel.com> <20250710150133.680679cf8a0f6b2f0bf3369f@linux-foundation.org> <20250711014947.GA863150@ax162> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250711014947.GA863150@ax162> On Thu, Jul 10, 2025 at 06:49:47PM -0700, Nathan Chancellor wrote: > On Fri, Jul 11, 2025 at 08:54:25AM +0800, Feng Tang wrote: > > On Thu, Jul 10, 2025 at 03:01:33PM -0700, Andrew Morton wrote: > > > On Thu, 10 Jul 2025 12:48:16 +0300 Andy Shevchenko wrote: > > > > > > > Compiler is not happy about the recently added code: > > > > > > > > lib/sys_info.c:52:19: error: variable 'sys_info_avail' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration] > > > > 52 | static const char sys_info_avail[] = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks"; > > > > | ^~~~~~~~~~~~~~ > > > > > > > > Fix it in the same way how, for example, lib/vsprintf.c does in the similar > > > > cases, i.e. by using string literal directly as sizeof() parameter. > > > > > > > > ... > > > > > > > > > > > --- a/lib/sys_info.c > > > > +++ b/lib/sys_info.c > > > > @@ -49,13 +49,11 @@ unsigned long sys_info_parse_param(char *str) > > > > > > > > #ifdef CONFIG_SYSCTL > > > > > > > > -static const char sys_info_avail[] = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks"; > > > > - > > > > int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write, > > > > void *buffer, size_t *lenp, > > > > loff_t *ppos) > > > > { > > > > - char names[sizeof(sys_info_avail) + 1]; > > > > + char names[sizeof("tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks") + 1]; > > > > struct ctl_table table; > > > > unsigned long *si_bits_global; > > > > > > > > > > Yes, that's neater than the fix we currently have. I'll grab, thanks. > > > > Hi Andrew, Andy, > > > > sys_info_avail[] has another purpose for being a counterpart of si_names[], > > which could be extended in future, so we make it obviously stand-alone. As > > for definition of si_names[], we explicitly added comment: > > > > /* > > * When 'si_names' gets updated, please make sure the 'sys_info_avail' > > * below is updated accordingly. > > */ > > static const struct sys_info_name si_names[] = { > > { SYS_INFO_TASKS, "tasks" }, > > { SYS_INFO_MEM, "mem" }, > > > > which has also been discussed in another thread: > > https://lore.kernel.org/lkml/aG3o2RFHc5iXnJef@U-2FWC9VHC-2323.local/ > > > > And I suggest to keep sys_info_avail[], and either Nathan or Sergey's patch > > works for me. > > We could do something like this to keep the sizeof() obvious and > separate, while still eliminating the variable? Happy to bike shed > aspects of it like the macro name and such. > > diff --git a/lib/sys_info.c b/lib/sys_info.c > index 46d6f4f1ad2a..c1df502a2c0d 100644 > --- a/lib/sys_info.c > +++ b/lib/sys_info.c > @@ -14,7 +14,7 @@ struct sys_info_name { > }; > > /* > - * When 'si_names' gets updated, please make sure the 'sys_info_avail' > + * When 'si_names' gets updated, please make sure SYS_INFO_MAX_LEN > * below is updated accordingly. > */ > static const struct sys_info_name si_names[] = { > @@ -49,13 +49,13 @@ unsigned long sys_info_parse_param(char *str) > > #ifdef CONFIG_SYSCTL > > -static const char sys_info_avail[] = "tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks"; > +#define SYS_INFO_MAX_LEN (sizeof("tasks,mem,timers,locks,ftrace,all_bt,blocked_tasks") + 1) > > int sysctl_sys_info_handler(const struct ctl_table *ro_table, int write, > void *buffer, size_t *lenp, > loff_t *ppos) > { > - char names[sizeof(sys_info_avail) + 1]; > + char names[SYS_INFO_MAX_LEN]; > struct ctl_table table; > unsigned long *si_bits_global; Looks great to me, thanks! We can even move the SYS_INFO_MAX_LEN definition close to si_names[], initially sys_info_avail[] was next to si_names[], and was moved inside "#ifdef CONFIG_SYSCTL" region for compiling CONFIG_SYSCTL=n case. > --- > > > Sorry for the inconvenience, and I should upgrade my gcc :) > > I am not sure that GCC has this warning, I have only ever seen it with > clang. Got it. Thanks, Feng