Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752847Ab3H0D3a (ORCPT ); Mon, 26 Aug 2013 23:29:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59266 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752302Ab3H0D33 (ORCPT ); Mon, 26 Aug 2013 23:29:29 -0400 Date: Mon, 26 Aug 2013 23:28:09 -0400 From: Naoya Horiguchi To: Wanpeng Li Cc: Andrew Morton , Andi Kleen , Fengguang Wu , Tony Luck , gong.chen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Message-ID: <1377574089-uu6o2agw-mutt-n-horiguchi@ah.jp.nec.com> In-Reply-To: <1377571171-9958-1-git-send-email-liwanp@linux.vnet.ibm.com> References: <1377571171-9958-1-git-send-email-liwanp@linux.vnet.ibm.com> Subject: Re: [PATCH v2 1/3] mm/hwpoison: fix bug triggered by unpoison empty zero page Mime-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Mutt-References: <1377571171-9958-1-git-send-email-liwanp@linux.vnet.ibm.com> X-Mutt-Fcc: ~/Maildir/sent/ User-Agent: Mutt 1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4621 Lines: 113 On Tue, Aug 27, 2013 at 10:39:29AM +0800, Wanpeng Li wrote: > v1 -> v2: > * ignore empty zero page for madvise_hwpoison directly > > [ 57.579580] Injecting memory failure for page 0x19d0 at 0xb77d2000 > [ 57.579824] MCE 0x19d0: non LRU page recovery: Ignored > [ 91.290453] MCE: Software-unpoisoned page 0x19d0 > [ 91.290456] BUG: Bad page state in process bash pfn:019d0 > [ 91.290466] page:f3461a00 count:0 mapcount:0 mapping: (null) index:0x0 > [ 91.290467] page flags: 0x40000404(referenced|reserved) > [ 91.290469] Modules linked in: nfsd auth_rpcgss i915 nfs_acl nfs lockd video drm_kms_helper drm bnep rfcomm sunrpc bluetooth psmouse parport_pc ppdev lp serio_raw fscache parport gpio_ich lpc_ich mac_hid i2c_algo_bit tpm_tis wmi usb_storage hid_generic usbhid hid e1000e firewire_ohci firewire_core ahci ptp libahci pps_core crc_itu_t > [ 91.290486] CPU: 3 PID: 2123 Comm: bash Not tainted 3.11.0-rc6+ #12 > [ 91.290487] Hardware name: LENOVO 7034DD7/ , BIOS 9HKT47AUS 01//2012 > [ 91.290488] 00000000 00000000 e9625ea0 c15ec49b f3461a00 e9625eb8 c15ea119 c17cbf18 > [ 91.290491] ef084314 000019d0 f3461a00 e9625ed8 c110dc8a f3461a00 00000001 00000000 > [ 91.290494] f3461a00 40000404 00000000 e9625ef8 c110dcc1 f3461a00 f3461a00 000019d0 > [ 91.290497] Call Trace: > [ 91.290501] [] dump_stack+0x41/0x52 > [ 91.290504] [] bad_page+0xcf/0xeb > [ 91.290515] [] free_pages_prepare+0x12a/0x140 > [ 91.290517] [] free_hot_cold_page+0x21/0x110 > [ 91.290519] [] __put_single_page+0x21/0x30 > [ 91.290521] [] put_page+0x25/0x40 > [ 91.290524] [] unpoison_memory+0x107/0x200 > [ 91.290526] [] ? ns_capable+0x27/0x60 > [ 91.290528] [] hwpoison_unpoison+0x20/0x30 > [ 91.290530] [] simple_attr_write+0xb6/0xd0 > [ 91.290532] [] ? generic_fh_to_dentry+0x50/0x50 > [ 91.290535] [] vfs_write+0xa0/0x1b0 > [ 91.290537] [] ? generic_fh_to_dentry+0x50/0x50 > [ 91.290539] [] SyS_write+0x4f/0x90 > [ 91.290549] [] sysenter_do_call+0x12/0x22 > [ 91.290550] Disabling lock debugging due to kernel taint > > Testcase: > > #define _GNU_SOURCE > #include > #include > #include > #include > #include > #include > #include > > #define PAGES_TO_TEST 1 > #define PAGE_SIZE 4096 > > int main(void) > { > char *mem; > > mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE, > PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); > > if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1) > return -1; > > munmap(mem, PAGES_TO_TEST * PAGE_SIZE); > > return 0; > } > > There is one page reference count for default empty zero page, madvise_hwpoison > add another one by get_user_pages_fast. memory_hwpoison reduce one page reference > count since it's a non LRU page. unpoison_memory release the last page reference > count and free empty zero page to buddy system which is not correct since empty > zero page has PG_reserved flag. This patch fix it by ignore empty zero page for > madvise_hwpoison directly. > > Suggested-by: Naoya Horiguchi > Signed-off-by: Wanpeng Li Thank you. Reviewed-by: Naoya Horiguchi > --- > mm/madvise.c | 2 ++ > mm/memory-failure.c | 3 +++ > 2 files changed, 5 insertions(+) > > diff --git a/mm/madvise.c b/mm/madvise.c > index 212f5f1..a20764c 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -352,6 +352,8 @@ static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end) > int ret = get_user_pages_fast(start, 1, 0, &p); > if (ret != 1) > return ret; > + if (page_to_pfn(p) == my_zero_pfn(0)) > + continue; > if (bhv == MADV_SOFT_OFFLINE) { > pr_info("Soft offlining page %#lx at %#lx\n", > page_to_pfn(p), start); > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 7cdabc0..68cbca0 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1331,6 +1331,9 @@ int unpoison_memory(unsigned long pfn) > if (!pfn_valid(pfn)) > return -ENXIO; > > + if (pfn == my_zero_pfn(0)) > + return 0; > + > p = pfn_to_page(pfn); > page = compound_head(p); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/