From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbdF2Iku (ORCPT ); Thu, 29 Jun 2017 04:40:50 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:42451 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752039AbdF2Ikq (ORCPT ); Thu, 29 Jun 2017 04:40:46 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.220.163 X-Original-MAILFROM: minchan@kernel.org Date: Thu, 29 Jun 2017 17:40:42 +0900 From: Minchan Kim To: "Kirill A. Shutemov" Cc: "Kirill A. Shutemov" , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Dave Hansen Subject: Re: [PATCH] thp, mm: Fix crash due race in MADV_FREE handling Message-ID: <20170629084042.GA22335@bbox> References: <20170628101249.17879-1-kirill.shutemov@linux.intel.com> <20170628101550.7uybtgfaejtxd7jv@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170628101550.7uybtgfaejtxd7jv@node.shutemov.name> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 28, 2017 at 01:15:50PM +0300, Kirill A. Shutemov wrote: > On Wed, Jun 28, 2017 at 01:12:49PM +0300, Kirill A. Shutemov wrote: > > Reinette reported following crash: > > > > BUG: Bad page state in process log2exe pfn:57600 > > page:ffffea00015d8000 count:0 mapcount:0 mapping: (null) index:0x20200 > > flags: 0x4000000000040019(locked|uptodate|dirty|swapbacked) > > raw: 4000000000040019 0000000000000000 0000000000020200 00000000ffffffff > > raw: ffffea00015d8020 ffffea00015d8020 0000000000000000 0000000000000000 > > page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set > > bad because of flags: 0x1(locked) > > Modules linked in: rfcomm 8021q bnep intel_rapl x86_pkg_temp_thermal coretemp efivars btusb btrtl btbcm pwm_lpss_pci snd_hda_codec_hdmi btintel pwm_lpss snd_hda_codec_realtek snd_soc_skl snd_hda_codec_generic snd_soc_skl_ipc spi_pxa2xx_platform snd_soc_sst_ipc snd_soc_sst_dsp i2c_designware_platform i2c_designware_core snd_hda_ext_core snd_soc_sst_match snd_hda_intel snd_hda_codec mei_me snd_hda_core mei snd_soc_rt286 snd_soc_rl6347a snd_soc_core efivarfs > > CPU: 1 PID: 354 Comm: log2exe Not tainted 4.12.0-rc7-test-test #19 > > Hardware name: Intel corporation NUC6CAYS/NUC6CAYB, BIOS AYAPLCEL.86A.0027.2016.1108.1529 11/08/2016 > > Call Trace: > > dump_stack+0x95/0xeb > > bad_page+0x16a/0x1f0 > > free_pages_check_bad+0x117/0x190 > > ? rcu_read_lock_sched_held+0xa8/0x130 > > free_hot_cold_page+0x7b1/0xad0 > > __put_page+0x70/0xa0 > > madvise_free_huge_pmd+0x627/0x7b0 > > madvise_free_pte_range+0x6f8/0x1150 > > ? debug_check_no_locks_freed+0x280/0x280 > > ? swapin_walk_pmd_entry+0x380/0x380 > > __walk_page_range+0x6b5/0xe30 > > walk_page_range+0x13b/0x310 > > madvise_free_page_range.isra.16+0xad/0xd0 > > ? force_swapin_readahead+0x110/0x110 > > ? swapin_walk_pmd_entry+0x380/0x380 > > ? lru_add_drain_cpu+0x160/0x320 > > madvise_free_single_vma+0x2e4/0x470 > > ? madvise_free_page_range.isra.16+0xd0/0xd0 > > ? vmacache_update+0x100/0x130 > > ? find_vma+0x35/0x160 > > SyS_madvise+0x8ce/0x1450 > > > > If somebody frees the page under us and we hold the last reference to > > it, put_page() would attempt to free the page before unlocking it. > > > > The fix is trivial reorder of operations. > > > > Signed-off-by: Kirill A. Shutemov > > Reported-by: Reinette Chatre > > Fixes: 9818b8cde622 ("madvise_free, thp: fix madvise_free_huge_pmd return value after splitting") > > Sorry, the wrong Fixes. The right one: > > Fixes: b8d3c4c3009d ("mm/huge_memory.c: don't split THP page when MADV_FREE syscall is called") > Acked-by: Minchan Kim Thanks.