From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx206.postini.com [74.125.245.206]) by kanga.kvack.org (Postfix) with SMTP id D988D6B005A for ; Mon, 26 Aug 2013 04:46:44 -0400 (EDT) Received: from /spool/local by e28smtp07.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 26 Aug 2013 14:07:31 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id EA6031258053 for ; Mon, 26 Aug 2013 14:16:29 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r7Q8mGIJ37683304 for ; Mon, 26 Aug 2013 14:18:17 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id r7Q8kaCI002353 for ; Mon, 26 Aug 2013 14:16:36 +0530 From: Wanpeng Li Subject: [PATCH v4 10/10] mm/hwpoison: fix bug triggered by unpoison empty zero page Date: Mon, 26 Aug 2013 16:46:14 +0800 Message-Id: <1377506774-5377-10-git-send-email-liwanp@linux.vnet.ibm.com> In-Reply-To: <1377506774-5377-1-git-send-email-liwanp@linux.vnet.ibm.com> References: <1377506774-5377-1-git-send-email-liwanp@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Andi Kleen , Fengguang Wu , Naoya Horiguchi , Tony Luck , gong.chen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li [ 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 don't reduce the page reference count under 1 against empty zero page. Signed-off-by: Wanpeng Li --- mm/memory-failure.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index fb687fd..be6b453 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1387,7 +1387,7 @@ int unpoison_memory(unsigned long pfn) unlock_page(page); put_page(page); - if (freeit) + if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1)) put_page(page); return 0; -- 1.8.1.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org