From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752872AbeEKL1Y (ORCPT ); Fri, 11 May 2018 07:27:24 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:39149 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752394AbeEKL1W (ORCPT ); Fri, 11 May 2018 07:27:22 -0400 X-Google-Smtp-Source: AB8JxZp63aPEq/0ngQL/JRcWFrqYz3ElI8bzdOK+oGxRDJ6/GAMKZAuTa6PtaF7ye9NKsoDKP9ftuA== Date: Fri, 11 May 2018 20:27:18 +0900 From: Sergey Senozhatsky To: Tetsuo Handa Cc: sergey.senozhatsky.work@gmail.com, pmladek@suse.com, dvyukov@google.com, sergey.senozhatsky@gmail.com, syzkaller@googlegroups.com, rostedt@goodmis.org, fengguang.wu@intel.com, linux-kernel@vger.kernel.org, peterz@infradead.org Subject: Re: [PATCH] printk: fix possible reuse of va_list variable Message-ID: <20180511112718.GA17477@jagdpanzerIV> References: <201805102350.JJH73950.tVJHQLFSOMOOFF@I-love.SAKURA.ne.jp> <20180511014515.GA895@jagdpanzerIV> <201805110238.w4B2cIGH079602@www262.sakura.ne.jp> <20180511062151.GA18160@jagdpanzerIV> <201805112002.GIF21216.OFVHFOMLJtQFSO@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201805112002.GIF21216.OFVHFOMLJtQFSO@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (05/11/18 20:02), Tetsuo Handa wrote: > I noticed that there is a possibility that printk_safe_log_store() causes > kernel oops because "args" parameter is passed to vsnprintf() again when > atomic_cmpxchg() detected that we raced. Fix this by using va_copy(). > > Signed-off-by: Tetsuo Handa > Fixes: 42a0bb3f71383b45 ("printk/nmi: generic solution for safe printk in NMI") > Cc: Sergey Senozhatsky > Cc: Petr Mladek > Cc: Peter Zijlstra > Cc: Steven Rostedt Reviewed-by: Sergey Senozhatsky -ss