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Wed, 10 Mar 2021 13:38:46 +0800 (HKT) Received: from alex-virtual-machine (172.16.253.254) by KSBJMAIL2.kingsoft.cn (10.88.1.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 10 Mar 2021 14:10:43 +0800 Date: Wed, 10 Mar 2021 14:10:42 +0800 From: Aili Yao To: "Luck, Tony" CC: "HORIGUCHI =?UTF-8?B?TkFPWUE=?=(=?UTF-8?B?5aCA5Y+j44CA55u05Lmf?=)" , Oscar Salvador , "david@redhat.com" , "akpm@linux-foundation.org" , "bp@alien8.de" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "yangfeng1@kingsoft.com" , Subject: Re: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Message-ID: <20210310141042.4db9ea29@alex-virtual-machine> In-Reply-To: References: <20210225181542.GA178925@agluck-desk2.amr.corp.intel.com> <20210226021907.GA27861@hori.linux.bs1.fc.nec.co.jp> <20210226105915.6cf7d2b8@alex-virtual-machine> <20210303033953.GA205389@agluck-desk2.amr.corp.intel.com> <20210303115710.2e9f8e23@alex-virtual-machine> <20210303163912.3d508e0f@alex-virtual-machine> <1a78e9abdc134e35a5efcbf6b2fd2263@intel.com> <20210304101653.546a9da1@alex-virtual-machine> <20210304121941.667047c3@alex-virtual-machine> <20210304144524.795872d7@alex-virtual-machine> <20210304235720.GA215567@agluck-desk2.amr.corp.intel.com> <20210305093016.40c87375@alex-virtual-machine> Organization: kingsoft X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable X-Originating-IP: [172.16.253.254] X-ClientProxiedBy: KSBJMAIL1.kingsoft.cn (10.88.1.31) To KSBJMAIL2.kingsoft.cn (10.88.1.32) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprNIsWRmVeSWpSXmKPExsXCFcGooJsW7ZFgcOGGpMWc9WvYLD5v+Mdm 8XX9L2aLaRvFLS6camCyuLxrDpvFvTX/WS0uHVjAZHGx8QCjxZlpRRabN01ltnhz4R6LxY8N j1kdeD2+t/axeCze85LJY9OqTjaPTZ8msXu8O3eO3ePEjN8sHi+ubmTxeL/vKpvH5tPVHp83 yXmcaPnCGsAdxWWTkpqTWZZapG+XwJXx7fgK5oIb6hXbT7UwNjB+luti5OSQEDCRmHR3CmsX IxeHkMB0JonFf+8zQjivGCWu7/jJ0sXIwcEioCqx6XMySAMbkLnr3ixWEFtEQE3i0uIHzCD1 zAKzWSVOTT7LDJIQFvCS+HJ/LSOIzStgJfHlygSwBk4BS4lPPavA4kICK1klPs/1ArH5BcQk eq/8Z4K4yF6ibcsiqF5BiZMzn7CA2MwCOhInVh1jhrC1JZYtfM0MMUdR4vCSX+wQvUoSR7pn sEHYsRLL5r1incAoPAvJqFlIRs1CMmoBI/MqRpbi3HSjTYyQ+AvdwTij6aPeIUYmDsZDjBIc zEoivH7H3RKEeFMSK6tSi/Lji0pzUosPMUpzsCiJ8+495pogJJCeWJKanZpakFoEk2Xi4JRq YGo4krt5a/A7Rqbm48f4pC6VfHqaL1U7922z1yHtPa2Tdtl0W3a4VxT9MG1euvHkneWqgal9 z6UiOq+4/n4+r8Glc1Wt9M2EzIsZE27rVEwW5Qo8oKRmZH/D6MOxdx4i7c7Bm9U/RdTFCDn6 iWsv+lnutKL254Oobe1bH39TmF1vOOWuwf91TZtWHIw3bLHeVfEvxUGV4+mLlbc2C7pabdid UnKW+XWd/3Unn8f27TbBt7gu71/a++DQyeBPbfk1l1mf897/ducI63e+H+uyi9e1mV8MeBNT O8XoyrptjQfadCy4BJxaGc/bnPjhrbek1PHRm2K3dcemVQi0CZ5WSdgl4aTYG8Mom/0xZvpF HSWW4oxEQy3mouJEAEtHZ50uAwAA X-Stat-Signature: smpus4zh4s89xd5gwyi6f7zyd4nixp5r X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 6094BC0007D1 Received-SPF: none (kingsoft.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=mail.kingsoft.com; client-ip=114.255.44.146 X-HE-DKIM-Result: none/none X-HE-Tag: 1615356646-536217 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, 5 Mar 2021 15:55:25 +0000 "Luck, Tony" wrote: > > From the walk, it seems we have got the virtual address, can we just se= nd a SIGBUS with it? =20 >=20 > If the walk wins the race and the pte for the poisoned page is still vali= d, then yes. >=20 > But we could have: >=20 > CPU1 CPU2 > memory_failure sets poison > bit for struct page >=20 >=20 > rmap finds page in task > on CPU2 and sets PTE > to not-valid-poison >=20 > memory_failure returns > early because struct page > already marked as poison >=20 > walk page tables looking > for mapping - don't find it >=20 > -Tony While I don't think there is a race condition, and if you really think the = pfn with SIGBUS is not proper, I think following patch maybe one way. I copy your abandon code, and make a little modification, and just now it p= ass my simple test. And also this is a RFC version, only valid if you think the pfn with SIGBUS= is not right. Thanks! =46rom a522ab8856e3a332a2318d57bb19f3c59594d462 Mon Sep 17 00:00:00 2001 From: Aili Yao Date: Wed, 10 Mar 2021 13:59:18 +0800 Subject: [PATCH] x86/mce: fix invalid SIGBUS address walk the current process pte and compare with the pfn; 1. only test for normal page and 2M hugetlb page; 2. 1G hugetlb and transparentHuge is not support currently; 3. May other fails is not recognized, This is a RFC version. --- arch/x86/kernel/cpu/mce/core.c | 83 ++++++++++++++++++++++++++++++++++++++= ++-- 1 file changed, 80 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index db4afc5..65d7ef7 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -28,8 +28,12 @@ #include #include #include +#include +#include +#include #include #include +#include #include #include #include @@ -1235,6 +1239,81 @@ static void __mc_scan_banks(struct mce *m, struct pt= _regs *regs, struct mce *fin /* mce_clear_state will clear *final, save locally for use later */ *m =3D *final; } +static int mc_pte_entry(pte_t *pte, unsigned long addr, unsigned long next= , struct mm_walk *walk) +{ + u64 *buff =3D (u64 *)walk->private; + u64 pfn =3D buff[0]; + + if (!pte_present(*pte) && is_hwpoison_entry(pte_to_swp_entry(*pte))) + goto find; + else if (pte_pfn(*pte) =3D=3D pfn) + goto find; + + return 0; +find: + buff[0] =3D addr; + buff[1] =3D PAGE_SHIFT; + return true; +} + +extern bool is_hugetlb_entry_hwpoisoned(pte_t pte); + +static int mc_hugetlb_range(pte_t *ptep, unsigned long hmask, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + u64 *buff =3D (u64 *)walk->private; + u64 pfn =3D buff[0]; + int shift =3D PMD_SHIFT; + pte_t pte =3D huge_ptep_get(ptep); + + if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) + goto find; + + if (pte_pfn(*ptep) =3D=3D pfn) + goto find; + + return 0; +find: + buff[0] =3D addr; + buff[1] =3D shift; + return true; +} + +static struct mm_walk_ops walk =3D { + .pte_entry =3D mc_pte_entry, + .hugetlb_entry =3D mc_hugetlb_range +}; + +void mc_memory_failure_error(struct task_struct *p, unsigned long pfn) +{ + u64 buff[2] =3D {pfn, 0}; + struct page *page; + int ret =3D -1; + + page =3D pfn_to_page(pfn); + if (!page) + goto force_sigbus; + + if (is_zone_device_page(page)) + goto force_sigbus; + + mmap_read_lock(p->mm); + ret =3D walk_page_range(p->mm, 0, TASK_SIZE_MAX, &walk, (void *)buff); + mmap_read_unlock(p->mm); + + if (ret && buff[0]) { + pr_err("Memory error may not recovered: %#llx: Sending SIGBUS to %s:%d d= ue to hardware memory corruption\n", + buff[0], p->comm, p->pid); + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)buff[0], buff[1]); + } else { +force_sigbus: + pr_err("Memory error may not recovered, pfn: %#lx: Sending SIGBUS to %s:= %d due to hardware memory corruption\n", + pfn, p->comm, p->pid); + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)pfn, PAGE_SHIFT); + } + +} =20 static void kill_me_now(struct callback_head *ch) { @@ -1259,9 +1338,7 @@ static void kill_me_maybe(struct callback_head *cb) } =20 if (p->mce_vaddr !=3D (void __user *)-1l) { - pr_err("Memory error may not recovered: %#lx: Sending SIGBUS to %s:%d du= e to hardware memory corruption\n", - p->mce_addr >> PAGE_SHIFT, p->comm, p->pid); - force_sig_mceerr(BUS_MCEERR_AR, p->mce_vaddr, PAGE_SHIFT); + mc_memory_failure_error(current, p->mce_addr >> PAGE_SHIFT); } else { pr_err("Memory error not recovered"); kill_me_now(cb); --=20 1.8.3.1 --=20 Thanks! Aili Yao