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=-5.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT 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 C572CC43441 for ; Fri, 9 Nov 2018 06:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8ACB720883 for ; Fri, 9 Nov 2018 06:47:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="ElkJIby2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8ACB720883 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ah.jp.nec.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728001AbeKIQ0n (ORCPT ); Fri, 9 Nov 2018 11:26:43 -0500 Received: from mail-pg1-f196.google.com ([209.85.215.196]:45590 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727366AbeKIQ0m (ORCPT ); Fri, 9 Nov 2018 11:26:42 -0500 Received: by mail-pg1-f196.google.com with SMTP id y4so435378pgc.12 for ; Thu, 08 Nov 2018 22:47:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=RtdH+8fxry6h6Pbb8TY5o2YMHv5QWx+98Zgkeuvb6yk=; b=ElkJIby278Z9CaOTZIBqEFv9pFIG/BYuKQHgnezzaRdylmojC0zbp8sBRtVX/oV8PC yHBNaT2B8o841kQMAdzwDZGY39pWLzykg7ApEESA4gMcaGk42bMEVpbfzW1z38Aatuo3 LHzq3XwPNzxzYKCURxEt9WeQ6/wCS5tLxGid6QSkWRiG3ohbmZ/XNCEOZPI30urS22cL pik/Y9uAs1WaHup86v7sr8O5anrg6+B4SIaah/7QZJKWtHLwtvSSHoJm0HabxjLfbGJw dGY4ptfGWhQfR4Qtl+EU/zbwdclwjpwLmSkKbzpNI64knX6ATyQ7s03LyiFtzJ8ypdLz 6nDQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=RtdH+8fxry6h6Pbb8TY5o2YMHv5QWx+98Zgkeuvb6yk=; b=CFp52yW+YJ4VdVNl2fXVMSCdk4PgRSVT/Irkp+jYpHgGfA3Hv2fljN8uRdL5zBhTrC BAQBxIs0wvJ3IwK/qxV6gGjYC21tmOf8+vztxZt8yOmucQMaOSQ3sSQ95zVbz0PyMiM3 touYMbUNJS7d7XIXyHdM1Eg5AoKoXtuC0AFp0arq+wBa0W4Umd7T550msd7n/hQ/Hvxy gKwOY5JLmJryMz9vUJJTTyCd17P0HPq1iAKziOapo0RoCCt9cmVNH4bl/f1/e7EGbC1A bUkoE4uhn+YhHPQbyXqGdLqurTYX8lKoRQxLzewY5X6MqJNIxOk6Ybj0nZFfbJqbMHEN hBXg== X-Gm-Message-State: AGRZ1gIA5El91/pn4zmjBYzuSRGULHQzxMfFi7rEhFHSyBxJWgfuw1EL 29XaotuUuYpt7hf/KaIWzg== X-Google-Smtp-Source: AJdET5dLYkKAGMikx0AVM1cpBD5gra2rJpxrwthuU9y4IFa1nzMP838s9nBknpVJS7aYq3HFCeZBkw== X-Received: by 2002:a62:7d10:: with SMTP id y16-v6mr7716522pfc.245.1541746053458; Thu, 08 Nov 2018 22:47:33 -0800 (PST) Received: from www9186uo.sakura.ne.jp (www9186uo.sakura.ne.jp. [153.121.56.200]) by smtp.gmail.com with ESMTPSA id c70-v6sm6808355pfg.97.2018.11.08.22.47.31 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Nov 2018 22:47:32 -0800 (PST) From: Naoya Horiguchi To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Michal Hocko , Andrew Morton , Mike Kravetz , xishi.qiuxishi@alibaba-inc.com, Laurent Dufour Subject: [RFC][PATCH v1 02/11] mm: soft-offline: add missing error check of set_hwpoison_free_buddy_page() Date: Fri, 9 Nov 2018 15:47:06 +0900 Message-Id: <1541746035-13408-3-git-send-email-n-horiguchi@ah.jp.nec.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com> References: <1541746035-13408-1-git-send-email-n-horiguchi@ah.jp.nec.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org set_hwpoison_free_buddy_page() could fail, then the target page is finally not isolated, so it's better to report -EBUSY for userspace to know the failure and chance of retry. And for consistency, this patch moves set_hwpoison_free_buddy_page() in unmap_and_move() to __soft_offline_page(). Fixes: 6bc9b56433b7 ("mm: fix race on soft-offlining free huge pages") Signed-off-by: Naoya Horiguchi --- mm/memory-failure.c | 15 ++++++++++++--- mm/migrate.c | 9 --------- 2 files changed, 12 insertions(+), 12 deletions(-) diff --git v4.19-mmotm-2018-10-30-16-08/mm/memory-failure.c v4.19-mmotm-2018-10-30-16-08_patched/mm/memory-failure.c index 9f09bf3..11e283e 100644 --- v4.19-mmotm-2018-10-30-16-08/mm/memory-failure.c +++ v4.19-mmotm-2018-10-30-16-08_patched/mm/memory-failure.c @@ -1719,14 +1719,18 @@ static int soft_offline_huge_page(struct page *page, int flags) /* * We set PG_hwpoison only when the migration source hugepage * was successfully dissolved, because otherwise hwpoisoned - * hugepage remains on free hugepage list, then userspace will - * find it as SIGBUS by allocation failure. That's not expected - * in soft-offlining. + * hugepage remains on free hugepage list. The allocator ignores + * such a hwpoisoned page so it's never allocated, but it could + * kill a process because of no-memory rather than hwpoison. + * Soft-offline never impacts the userspace, so this is + * undesired. */ ret = dissolve_free_huge_page(page); if (!ret) { if (set_hwpoison_free_buddy_page(page)) num_poisoned_pages_inc(); + else + ret = -EBUSY; } } return ret; @@ -1804,6 +1808,11 @@ static int __soft_offline_page(struct page *page, int flags) pfn, ret, page->flags, &page->flags); if (ret > 0) ret = -EIO; + } else { + if (set_hwpoison_free_buddy_page(page)) + num_poisoned_pages_inc(); + else + ret = -EBUSY; } } else { pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx (%pGp)\n", diff --git v4.19-mmotm-2018-10-30-16-08/mm/migrate.c v4.19-mmotm-2018-10-30-16-08_patched/mm/migrate.c index f7e4bfd..1742372 100644 --- v4.19-mmotm-2018-10-30-16-08/mm/migrate.c +++ v4.19-mmotm-2018-10-30-16-08_patched/mm/migrate.c @@ -1199,15 +1199,6 @@ static ICE_noinline int unmap_and_move(new_page_t get_new_page, */ if (rc == MIGRATEPAGE_SUCCESS) { put_page(page); - if (reason == MR_MEMORY_FAILURE) { - /* - * Set PG_HWPoison on just freed page - * intentionally. Although it's rather weird, - * it's how HWPoison flag works at the moment. - */ - if (set_hwpoison_free_buddy_page(page)) - num_poisoned_pages_inc(); - } } else { if (rc != -EAGAIN) { if (likely(!__PageMovable(page))) { -- 2.7.0