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=-8.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 2F2C1C433E6 for ; Tue, 23 Feb 2021 23:01:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 02D6A64E7A for ; Tue, 23 Feb 2021 23:01:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233927AbhBWXAP (ORCPT ); Tue, 23 Feb 2021 18:00:15 -0500 Received: from mx2.suse.de ([195.135.220.15]:49214 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232598AbhBWWqY (ORCPT ); Tue, 23 Feb 2021 17:46:24 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6A642AC69; Tue, 23 Feb 2021 22:45:42 +0000 (UTC) Date: Tue, 23 Feb 2021 23:45:40 +0100 From: Oscar Salvador To: Mike Kravetz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Gerald Schaefer , Michal Hocko , Muchun Song , Heiko Carstens , Sven Schnelle , Andrew Morton Subject: Re: [PATCH] hugetlb: fix uninitialized subpool pointer Message-ID: <20210223224540.GB2740@localhost.localdomain> References: <20210223215544.313871-1-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210223215544.313871-1-mike.kravetz@oracle.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 23, 2021 at 01:55:44PM -0800, Mike Kravetz wrote: > Gerald Schaefer reported a panic on s390 in hugepage_subpool_put_pages() > with linux-next 5.12.0-20210222. > Call trace: > hugepage_subpool_put_pages.part.0+0x2c/0x138 > __free_huge_page+0xce/0x310 > alloc_pool_huge_page+0x102/0x120 > set_max_huge_pages+0x13e/0x350 > hugetlb_sysctl_handler_common+0xd8/0x110 > hugetlb_sysctl_handler+0x48/0x58 > proc_sys_call_handler+0x138/0x238 > new_sync_write+0x10e/0x198 > vfs_write.part.0+0x12c/0x238 > ksys_write+0x68/0xf8 > do_syscall+0x82/0xd0 > __do_syscall+0xb4/0xc8 > system_call+0x72/0x98 > > This is a result of the change which moved the hugetlb page subpool > pointer from page->private to page[1]->private. When new pages are > allocated from the buddy allocator, the private field of the head > page will be cleared, but the private field of subpages is not modified. > Therefore, old values may remain. > > Fix by initializing hugetlb page subpool pointer in prep_new_huge_page(). > > Fixes: f1280272ae4d ("hugetlb: use page.private for hugetlb specific page flags") > Reported-by: Gerald Schaefer > Signed-off-by: Mike Kravetz Do we need the hugetlb_set_page_subpool() in __free_huge_page? Reviewed-by: Oscar Salvador -- Oscar Salvador SUSE L3