From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f199.google.com (mail-pf0-f199.google.com [209.85.192.199]) by kanga.kvack.org (Postfix) with ESMTP id 383AD6B0005 for ; Tue, 19 Jul 2016 06:16:46 -0400 (EDT) Received: by mail-pf0-f199.google.com with SMTP id e189so28621116pfa.2 for ; Tue, 19 Jul 2016 03:16:46 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTP id p64si8781988pfg.128.2016.07.19.03.16.40 for ; Tue, 19 Jul 2016 03:16:42 -0700 (PDT) Message-ID: <578DF872.3050507@huawei.com> Date: Tue, 19 Jul 2016 17:52:50 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH] mm/hugetlb: fix race when migrate pages. References: <1468897140-43471-1-git-send-email-zhongjiang@huawei.com> <20160719091724.GD9490@dhcp22.suse.cz> In-Reply-To: <20160719091724.GD9490@dhcp22.suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: akpm@linux-foundation.org, vbabka@suse.cz, rientjes@google.com, qiuxishi@huawei.com, linux-mm@kvack.org On 2016/7/19 17:17, Michal Hocko wrote: > On Tue 19-07-16 10:59:00, zhongjiang wrote: >> From: zhong jiang >> >> I hit the following problem when run the database and online-offline memory >> in the system. >> The kernel version is 3.10. but I think the mainline have some question to >> be solved. >> >> kernel BUG at arch/x86/mm/hugetlbpage.c:161! >> [154364.730387] invalid opcode: 0000 [#1] SMP >> [154364.734795] Modules linked in: nls_utf8 isofs loop signo_catch(OV) iTCO_wdt iTCO_vendor_support coretemp vfat intel_rapl fat kvm_intel kvm crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw gf128mul glue_helper ablk_helper cryptd pcspkr sb_edac edac_core i2c_i801 lpc_ich ses i2c_core mfd_core enclosure mei_me mei shpchp wmi ipmi_devintf ipmi_si ipmi_msghandler binfmt_misc xfs libcrc32c sd_mod crc_t10dif crct10dif_common ahci l ibahci tg3 ptp libata pps_core megaraid_sas dm_mirror dm_region_hash dm_log dm_mod >> [154364.786831] CPU: 171 PID: 700733 Comm: oracle Tainted: G O ----V------- 3.10.0-229.30.1.44.hulk.x86_64 #1 SMP Fri Jun 24 13:02:35 CST 2016 >> [154364.809927] task: ffff8826bb0cae00 ti: ffff8826a36c4000 task.ti: ffff8826a36c4000 >> [154364.817541] RIP: 0010:[] [] huge_pte_alloc+0x452/0x4d0 >> [154364.826135] RSP: 0018:ffff8826a36c7c58 EFLAGS: 00010246 >> [154364.831583] RAX: ffff882609e16350 RBX: ffff88180845d000 RCX: ffff880000000000 >> [154364.838848] RDX: 0000014538fc0000 RSI: 0000005d0d400000 RDI: 0000002609e16067 >> [154364.846111] RBP: ffff8826a36c7c98 R08: ffff880000000000 R09: ffff88265b2f83e0 >> [154364.853378] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000200000 >> [154364.860641] R13: ffff88190475dba0 R14: ffff880000000350 R15: 0000005d0d400000 >> [154364.867908] FS: 00007ff87a54a740(0000) GS:ffff88001dc60000(0000) knlGS:0000000000000000 >> [154364.876123] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [154364.882004] CR2: 00007f61b8ebee14 CR3: 00000025f3a16000 CR4: 00000000001407e0 >> [154364.889270] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> [154364.896533] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> [154364.903797] Stack: >> [154364.905960] ffff88265b2f83f8 ffff882609e16000 ffff880a8fc88c80 ffff882609e16350 >> [154364.914096] ffff882609e16348 ffffffff81e41060 ffff880a8fc88c80 0000005d0d400000 >> [154364.922224] ffff8826a36c7d18 ffffffff8119c322 0000005e20000000 00000000e0000000 >> [154364.930357] Call Trace: >> [154364.933045] [] copy_hugetlb_page_range+0x152/0x2f0 >> [154364.939702] [] copy_page_range+0x3d9/0x480 >> [154364.945654] [] ? vma_gap_callbacks_rotate+0x1e/0x30 >> [154364.952402] [] ? __rb_insert_augmented+0x8f/0x1f0 >> [154364.958957] [] ? __vma_link_rb+0xb8/0xe0 >> [154364.964743] [] dup_mm+0x357/0x660 >> [154364.969915] [] copy_process.part.25+0xa3b/0x14b0 >> [154364.976384] [] do_fork+0xbc/0x350 >> [154364.981569] [] ? get_unused_fd_flags+0x30/0x40 >> [154364.987864] [] SyS_clone+0x16/0x20 >> [154364.993140] [] stub_clone+0x69/0x90 >> [154364.998483] [] ? system_call_fastpath+0x16/0x1b > OK, so this states the problem. Although it would be helpful to be > specific about which BUG has triggered because the above line doesn't > match any in the current code. I assume this is > > BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)) > > in huge_pte_alloc. Now the changelog is silent about what the actual > problem is and what is the fix. Could you add this information please? Yes, it hit this BUG_ON() you had mentioned. The pmd share function enable, when I run online-offline memory , That will lead to pte_huge() return false. beacuse it refer to the pmd may be ongoing migration. Thanks zhong jiang >> Signed-off-by: zhong jiang >> --- >> mm/hugetlb.c | 9 ++++++++- >> 1 file changed, 8 insertions(+), 1 deletion(-) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 6384dfd..1b54d7a 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -4213,13 +4213,14 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) >> struct vm_area_struct *svma; >> unsigned long saddr; >> pte_t *spte = NULL; >> - pte_t *pte; >> + pte_t *pte, entry; >> spinlock_t *ptl; >> >> if (!vma_shareable(vma, addr)) >> return (pte_t *)pmd_alloc(mm, pud, addr); >> >> i_mmap_lock_write(mapping); >> +retry: >> vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { >> if (svma == vma) >> continue; >> @@ -4240,6 +4241,12 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) >> >> ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); >> spin_lock(ptl); >> + entry = huge_ptep_get(spte); >> + if (is_hugetlb_entry_migration(entry) || >> + is_hugetlb_entry_hwpoisoned(entry)) { >> + spin_unlock(ptl); >> + goto retry; >> + } >> if (pud_none(*pud)) { >> pud_populate(mm, pud, >> (pmd_t *)((unsigned long)spte & PAGE_MASK)); >> -- >> 1.8.3.1 >> >> -- >> 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 -- 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