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=-17.6 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_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 B2A22C5ACAE for ; Thu, 12 Sep 2019 02:31:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4E7992082C for ; Thu, 12 Sep 2019 02:31:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="POAOLSgR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E7992082C 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 B2E8B6B0003; Wed, 11 Sep 2019 22:31:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B052E6B0005; Wed, 11 Sep 2019 22:31:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F52D6B0006; Wed, 11 Sep 2019 22:31:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0203.hostedemail.com [216.40.44.203]) by kanga.kvack.org (Postfix) with ESMTP id 7CC3B6B0003 for ; Wed, 11 Sep 2019 22:31:16 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 23B58824376D for ; Thu, 12 Sep 2019 02:31:16 +0000 (UTC) X-FDA: 75924691752.01.music96_453af081ca33b X-HE-Tag: music96_453af081ca33b X-Filterd-Recvd-Size: 4025 Received: from mail-pf1-f201.google.com (mail-pf1-f201.google.com [209.85.210.201]) by imf17.hostedemail.com (Postfix) with ESMTP for ; Thu, 12 Sep 2019 02:31:15 +0000 (UTC) Received: by mail-pf1-f201.google.com with SMTP id f2so17204283pfk.13 for ; Wed, 11 Sep 2019 19:31:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=M01d621+jXOeVOtLJvHlUCtiCRQEegusNaDlr2i35Sc=; b=POAOLSgRgwPfDzOISo1MKH/2QLeqTomKY/wS1QotRgVb+fnKfk6pEqTsN/5no3Yb3S Q5gAVgxxV+ZQKy+l3JYU/B1KiQJSM9FrAz+2rSwbmQm+8ozbJxvc6yf9QD2AWui2kVQF IHnCKQWi3MGZhSBAFzveRDOPGWpx/LU/lf39HC0SpCVhsnAg+l9peNmmIjSehuOq1RVW M/MRonGRnTVovm/fmrHgANDs4dtA5VQw1clG8EniSSFxLN36ZtbuwWeoVt164qoMELUZ X/rjZ1tQSHJA/LTXAUcXSM2SQMofSmH/P5odvUxHBR6hhvJsflCDHFpxxx5hCHaSOMcp tEvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=M01d621+jXOeVOtLJvHlUCtiCRQEegusNaDlr2i35Sc=; b=eHQTctRjdico+T8g5+x7Pla0dR01J5JC/+J7E8G+d0R4q/NGbWoP3H2c6QqJ4w35AY FFRbvHqA27qpv6hzo9Ci8mNBkmEZSMK0zBPdj8yceq+/4gPVduoJroLs/xfAvErbbuiL VoA/I3IP8rY4cqxnRN+dHZPxeTiktqnK0ku3SiWtIAfgH5I+QTLnQHyuxkmsfa89/qWs uAnPRncuT+V1AzfRclV1lUW7ckCmvqRYuqQo3sOVGkTTf24ZRWnMWnt1USUgqGrvhvg5 3qVMe8qX2CG/RKgs29PDZHy8TNNFGRJwoiJvuzQMZLWxDWMu1V2MPTfAISgLQFyVFlqN t54Q== X-Gm-Message-State: APjAAAUzuiagoyqhlMSt6SUNQjf+QG22wIvo1CqhIQXgoZ3rV8zVR6Qc Ej9DGj1/MAuNJZC+tDzTmNcxbXlRZ5E= X-Google-Smtp-Source: APXvYqyWlP3NAwE+jBFawlowdpRiaR5zP9SQNymsUcqOg03NykdEEjCnMCVUr+qahjil0jS9sKtiPxp+PvI= X-Received: by 2002:a65:6546:: with SMTP id a6mr36882579pgw.220.1568255474084; Wed, 11 Sep 2019 19:31:14 -0700 (PDT) Date: Wed, 11 Sep 2019 20:31:08 -0600 In-Reply-To: <20190912004401.jdemtajrspetk3fh@box> Message-Id: <20190912023111.219636-1-yuzhao@google.com> Mime-Version: 1.0 References: <20190912004401.jdemtajrspetk3fh@box> X-Mailer: git-send-email 2.23.0.162.g0b9fbb3734-goog Subject: [PATCH v2 1/4] mm: correct mask size for slub page->objects From: Yu Zhao To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , "Kirill A . Shutemov" , Tetsuo Handa Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yu Zhao 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: Mask of slub objects per page shouldn't be larger than what page->objects can hold. It requires more than 2^15 objects to hit the problem, and I don't think anybody would. It'd be nice to have the mask fixed, but not really worth cc'ing the stable. Fixes: 50d5c41cd151 ("slub: Do not use frozen page flag but a bit in the page counters") Signed-off-by: Yu Zhao --- mm/slub.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 8834563cdb4b..62053ceb4464 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -187,7 +187,7 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) */ #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) -#define OO_SHIFT 16 +#define OO_SHIFT 15 #define OO_MASK ((1 << OO_SHIFT) - 1) #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */ @@ -343,6 +343,8 @@ static inline unsigned int oo_order(struct kmem_cache_order_objects x) static inline unsigned int oo_objects(struct kmem_cache_order_objects x) { + BUILD_BUG_ON(OO_MASK > MAX_OBJS_PER_PAGE); + return x.x & OO_MASK; } -- 2.23.0.162.g0b9fbb3734-goog