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=-14.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham 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 71B7BC2BA19 for ; Tue, 14 Apr 2020 14:37:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 255032064A for ; Tue, 14 Apr 2020 14:37:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="j1mQzCto" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 255032064A Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C5A0C8E0003; Tue, 14 Apr 2020 10:37:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C09F98E0001; Tue, 14 Apr 2020 10:37:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AF8A38E0003; Tue, 14 Apr 2020 10:37:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0083.hostedemail.com [216.40.44.83]) by kanga.kvack.org (Postfix) with ESMTP id 96FA38E0001 for ; Tue, 14 Apr 2020 10:37:30 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 51DF98245571 for ; Tue, 14 Apr 2020 14:37:30 +0000 (UTC) X-FDA: 76706713860.15.side66_73f8e92b1f24 X-HE-Tag: side66_73f8e92b1f24 X-Filterd-Recvd-Size: 6673 Received: from mail-pf1-f194.google.com (mail-pf1-f194.google.com [209.85.210.194]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Tue, 14 Apr 2020 14:37:29 +0000 (UTC) Received: by mail-pf1-f194.google.com with SMTP id n10so11030pff.3 for ; Tue, 14 Apr 2020 07:37:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jRmuMhrqGSsWEOJ70Fo+XRuVWURTgHtEO/ORU5JOdm4=; b=j1mQzCtoT/ttPF/FRbcRDccDapTkLGwvuoRSOaDCdXB2/46p9BqFlfhUj9a6QtIaIv O0+dlj+jdyhCQ+5ivqUNZGfZ2CkH0ppNk+ZGRt5Vx+W2Bbc1ybxkxCCUekJuF/3W/a9M G9J+cPOQfM1SEOSaqbWNpa2Z+MxINY6qpiN9s7aa+XMBoZCEKKgnt04DgfcpzASL2DWK Ik38VmsMu+ud+G8jRl7/m5sce3Oxu8n4YzwyBLw+iYAMZyBwLLT2rbaZcMDQRvqhz0jE 5eJ0MC8fi2X9a7qKkUF6LSmA4egqLxlkk1j691hc/8yh8jK+Ulh2KWnhP1uRounq0iBT ciFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jRmuMhrqGSsWEOJ70Fo+XRuVWURTgHtEO/ORU5JOdm4=; b=N6Nqa1r2RMwxmhPjHjq2AwPoZOgJOEnw0TbrivCaAbjW3CRDsAF5eYcUmpgvKhTr6h KW4hd2Mejuy3SZS9g6kgkMRQ3LkyD1ae481Pjd9ZM4D5woA83PCNKnaVcAQGsxOH8wRu LX0vxR6H8GM13v/E8zKTmtBzhQA7jC1Pin2z0GJF4Meu6zSuc1+ODZWAYGtqDjRetMoG BpLXr8iSS9oKFv0eoPsZh1dp4LVjkJbdQf8e+32Xn8+LtgtD96Kr4sxK+MlIg8YsAGHz YapuPFuslN3nhQiPmcXkpKUeGyTLlHxnedSgs4/QDu8SOI02PhlVVQMT/dKk3k+q6p7P KoiA== X-Gm-Message-State: AGi0PuZsmDEAPdCzmF573Ok1JXvNU+QlY2CpOKhOYq90jnptB4Y8ThQy 8vlO1yeZHasAS5dAUj2P4GegDU26XehybfpT/80TFA== X-Google-Smtp-Source: APiQypL38lNWHB1LMCE7kzuXMOoQXBW5+1ake7WJPmlmpnuLrgDPajld2ZPS0AxOy6szZ9Ldl0SU8HocUXxr6QiyA58= X-Received: by 2002:a63:f411:: with SMTP id g17mr21930190pgi.440.1586875048464; Tue, 14 Apr 2020 07:37:28 -0700 (PDT) MIME-Version: 1.0 References: <20200325161249.55095-1-glider@google.com> <20200325161249.55095-24-glider@google.com> In-Reply-To: <20200325161249.55095-24-glider@google.com> From: Andrey Konovalov Date: Tue, 14 Apr 2020 16:37:16 +0200 Message-ID: Subject: Re: [PATCH v5 23/38] kmsan: printk: treat the result of vscnprintf() as initialized To: Alexander Potapenko Cc: Andrew Morton , Greg Kroah-Hartman , Eric Dumazet , Wolfram Sang , Petr Mladek , Vegard Nossum , Dmitry Vyukov , Marco Elver , Linux Memory Management List , Alexander Viro , Andreas Dilger , Andrey Ryabinin , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Christoph Hellwig , Christoph Hellwig , "Darrick J. Wong" , "David S. Miller" , Dmitry Torokhov , Eric Biggers , Eric Van Hensbergen , Harry Wentland , Herbert Xu , Ilya Leoshkevich , Ingo Molnar , Jason Wang , Jens Axboe , Marek Szyprowski , Mark Rutland , "Martin K. Petersen" , Martin Schwidefsky , Matthew Wilcox , "Michael S . Tsirkin" , Michal Hocko , Michal Simek , Qian Cai , Randy Dunlap , Robin Murphy , Sergey Senozhatsky , Steven Rostedt , Takashi Iwai , "Theodore Ts'o" , Thomas Gleixner , Vasily Gorbik Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Mar 25, 2020 at 5:14 PM wrote: > > In vprintk_store(), vscnprintf() may return an uninitialized text_len > value if any of its arguments are uninitialized. In that case KMSAN will > report one or more errors in vscnprintf() itself, but it doesn't make > much sense to track that value further, as it may trigger more errors in > printk. Instead, we explicitly mark it as initialized. > > Signed-off-by: Alexander Potapenko > To: Alexander Potapenko > Cc: Andrew Morton > Cc: Greg Kroah-Hartman > Cc: Eric Dumazet > Cc: Wolfram Sang > Cc: Petr Mladek > Cc: Vegard Nossum > Cc: Dmitry Vyukov > Cc: Marco Elver > Cc: Andrey Konovalov > Cc: linux-mm@kvack.org > Acked-by: Petr Mladek Reviewed-by: Andrey Konovalov > > --- > > This patch was split from "kmsan: call KMSAN hooks where needed", as > requested by Andrey Konovalov. Petr Mladek has previously acked the > printk part of that patch, hence the Acked-by above. > > v4: > - split this patch away > > Change-Id: Ibed60b0bdd25f8ae91acee5800b5328e78e0735a > --- > kernel/printk/printk.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index ad46062345452..4cadba3c1e68d 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -1913,6 +1913,12 @@ int vprintk_store(int facility, int level, > * prefix which might be passed-in as a parameter. > */ > text_len = vscnprintf(text, sizeof(textbuf), fmt, args); > + /* > + * If any of vscnprintf() arguments is uninitialized, KMSAN will report > + * one or more errors and also probably mark text_len as uninitialized. > + * Initialize |text_len| to prevent the errors from spreading further. > + */ > + text_len = KMSAN_INIT_VALUE(text_len); > > /* mark and strip a trailing newline */ > if (text_len && text[text_len-1] == '\n') { > -- > 2.25.1.696.g5e7596f4ac-goog >