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Wed, 17 Mar 2021 15:50:11 +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, 17 Mar 2021 16:23:05 +0800 Date: Wed, 17 Mar 2021 16:23:04 +0800 From: Aili Yao To: "HORIGUCHI =?UTF-8?B?TkFPWUE=?=(=?UTF-8?B?5aCA5Y+j44CA55u05Lmf?=)" CC: "Luck, Tony" , "akpm@linux-foundation.org" , Oscar Salvador , "david@redhat.com" , "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: <20210317162304.58ff188c@alex-virtual-machine> In-Reply-To: <20210317154812.4173f423@alex-virtual-machine> References: <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> <20210310141042.4db9ea29@alex-virtual-machine> <20210311085529.GA22268@hori.linux.bs1.fc.nec.co.jp> <20210317154812.4173f423@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+NgFprNIsWRmVeSWpSXmKPExsXCFcGooLt5S2CCwflHQhZz1q9hs/i84R+b xdf1v5gtpm0Ut7hwqoHJ4vKuOWwW99b8Z7W4dGABk8XFxgOMFmemFVls3jSV2eLNhXssFj82 PGZ14PX43trH4rF4z0smj02rOtk8Nn2axO7x7tw5do8TM36zeLy4upHF4/2+q2wem09Xe3ze JOdxouULawB3FJdNSmpOZllqkb5dAlfGx2aZgllWFfcOJDUwtup3MXJySAiYSGz4upSli5GL Q0hgOpPE8pkTGCGcV4wSC7atZQapYhFQlfi1ezcTiM0GZO+6N4sVxBYRSJJYPPsrE0gDs8B3 FoknV7eAFQkLeEl8ub+WEcTmFbCSmDG3nR3E5hSwltj87j8rxIZHLBIHZu1lA0nwC4hJ9F75 zwRxk71E25ZFUM2CEidnPmEBsZkFdCROrDrGDGFrSyxb+BrMFhJQlDi85Bc7RK+SxJHuGWwQ dqzEsnmvWCcwCs9CMmoWklGzkIxawMi8ipGlODfdaBMjJP5CdzDOaPqod4iRiYPxEKMEB7OS CK9pXkCCEG9KYmVValF+fFFpTmrxIUZpDhYlcV7HSKCUQHpiSWp2ampBahFMlomDU6qB6bbk erbwsktHc/6ET/DufuCcJRb66P7OLVd7mNh7tASOH3E6mnZfjKVz6wXhB1OFHBueP5Xx2GHv Ep779+LKvyFzwxK4i5s2ahWVMNgyCF7Pqw+4Y7+8pdA7UEpU54sd39mN5Z+V0w2sFa3/BXPt FFr3zHCu5NTosmVv+/c83tRSE7Xw3CweXaHTf0wOr9k9S2LtVAGzOW9Vd9zWeLo5I7RW8plB dcdKI6FuqT0yLxS37ExbwcT5l60pZc2Z2y0Lr5jYaWUJXtVz3fBg7sLVCZsNOr1dS8KiHvEK nDU9EanydOm1yTuvqJ59tm83Z7QKQ4btt0mzD6xhev8zIiu6TO/xQus/b8895PYTrvPMUmIp zkg01GIuKk4EAMr+zukuAwAA X-Stat-Signature: f6nbgna9mombw3hneq3fpun9mhqk6wmy X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 741D7138 Received-SPF: none (kingsoft.com>: No applicable sender policy available) receiver=imf12; identity=mailfrom; envelope-from=""; helo=mail.kingsoft.com; client-ip=114.255.44.145 X-HE-DKIM-Result: none/none X-HE-Tag: 1615969388-203785 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: > >=20 > > Returning true means you stop walking when you find the first entry poi= nting > > to a given pfn. But there could be multiple such entries, so if MCE SRA= R is > > triggered by memory access to the larger address in hwpoisoned entries,= the > > returned virtual address might be wrong. > > =20 >=20 > I can't find the way to fix this, maybe the virtual address is contained = in > related register, but this is really beyong my knowledge. >=20 > This is a v2 RFC patch, add support for thp and 1G huge page errors. >=20 Sorry for the debug info and other unclean modifications. Post a clean one. Thanks Aili Yao =46rom 2289276ba943cdcddbf3b5b2cdbcaff78690e2e8 Mon Sep 17 00:00:00 2001 From: Aili Yao Date: Wed, 17 Mar 2021 16:12:41 +0800 Subject: [PATCH] fix invalid SIGBUS address for recovery fail Walk the current process pages and compare with the pfn, then get the user address and related page_shift. For thp pages, we can only split anonoums thp page, so I think there may be no race condition for walking and searching the thp error page for such case; For non anonymous thp, the page flag and pte will not be change. so when code goes into this place, it may be race condition for non-anonoums thp page or from a recovery fail for anonoums thp, the page status will not change, i am not so sure about this; For the case we don't find the related virtual address, Maybe sending one BUS_MCEERR_AR signal with invalid address NULL is a better option, but i am not sure. And this may get the wrong virtual address if process have multiple entry for a same page, I don't find a way to get it correct. Maybe other issues is not recognized. --- arch/x86/kernel/cpu/mce/core.c | 12 +--- include/linux/mm.h | 1 + mm/memory-failure.c | 127 +++++++++++++++++++++++++++++++++++++= ++++ 3 files changed, 131 insertions(+), 9 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index db4afc5..4cb873c 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -1246,7 +1246,7 @@ static void kill_me_maybe(struct callback_head *cb) struct task_struct *p =3D container_of(cb, struct task_struct, mce_kill_m= e); int flags =3D MF_ACTION_REQUIRED; =20 - pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce= _addr); + pr_err("Uncorrected hardware memory error in user-access at %llx\n", p->m= ce_addr); =20 if (!p->mce_ripv) flags |=3D MF_MUST_KILL; @@ -1258,14 +1258,8 @@ static void kill_me_maybe(struct callback_head *cb) return; } =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); - } else { - pr_err("Memory error not recovered"); - kill_me_now(cb); - } + memory_failure_error(current, p->mce_addr >> PAGE_SHIFT); + } =20 static void queue_task_work(struct mce *m, int kill_current_task) diff --git a/include/linux/mm.h b/include/linux/mm.h index ecdf8a8..cff2f02 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3046,6 +3046,7 @@ enum mf_flags { MF_SOFT_OFFLINE =3D 1 << 3, }; extern int memory_failure(unsigned long pfn, int flags); +extern void memory_failure_error(struct task_struct *p, unsigned long pfn); extern void memory_failure_queue(unsigned long pfn, int flags); extern void memory_failure_queue_kick(int cpu); extern int unpoison_memory(unsigned long pfn); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 06f0061..359b42f 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -56,6 +56,7 @@ #include #include #include +#include #include "internal.h" #include "ras/ras_event.h" =20 @@ -1553,6 +1554,132 @@ int memory_failure(unsigned long pfn, int flags) } EXPORT_SYMBOL_GPL(memory_failure); =20 +static int pte_range(pte_t *ptep, unsigned long addr, unsigned long next, = struct mm_walk *walk) +{ + u64 *buff =3D (u64 *)walk->private; + u64 pfn =3D buff[0]; + pte_t pte =3D *ptep; + + if (!pte_none(pte) && !pte_present(pte)) { + swp_entry_t swp_temp =3D pte_to_swp_entry(pte); + + if (is_hwpoison_entry(swp_temp) && swp_offset(swp_temp) =3D=3D pfn) + 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; +} + +static int pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + u64 *buff =3D (u64 *)walk->private; + struct page *page =3D (struct page *)buff[0]; + u64 pfn =3D buff[1]; + pmd_t pmd =3D *pmdp; + + if (likely(!pmd_trans_huge(pmd))) + return 0; + + if (pmd_none(pmd) || !pmd_present(pmd)) + return 0; + + if (pmd_page(pmd) !=3D page) + return 0; + + for (; addr !=3D end; page++, addr +=3D PAGE_SIZE) { + if (page_to_pfn(page) =3D=3D pfn) { + buff[0] =3D addr; + buff[1] =3D PAGE_SHIFT; + return true; + } + } + + return 0; +} + +static int 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]; + pte_t pte =3D huge_ptep_get(ptep); + struct page *page =3D pfn_to_page(pfn); + + if (!huge_pte_none(pte) && !pte_present(pte)) { + swp_entry_t swp_temp =3D pte_to_swp_entry(pte); + + if (is_hwpoison_entry(swp_temp) && swp_offset(swp_temp) =3D=3D pfn) + goto find; + } + if (pte_pfn(pte) =3D=3D pfn) + goto find; + + return 0; + +find: + buff[0] =3D addr; + buff[1] =3D (huge_page_size(page_hstate(page)) > PMD_SIZE) ? PUD_SHIFT : = PMD_SHIFT; + return true; +} + +void memory_failure_error(struct task_struct *p, unsigned long pfn) +{ + u64 buff[2] =3D {0}; + struct page *page; + int ret =3D -1; + struct mm_walk_ops walk =3D {0}; + + if (p->mce_vaddr !=3D (void __user *)-1l && p->mce_vaddr !=3D (void __use= r *)0) { + force_sig_mceerr(BUS_MCEERR_AR, p->mce_vaddr, PAGE_SHIFT); + return; + } + + page =3D pfn_to_page(pfn); + if (!page) + goto force_sigbus; + + if (is_zone_device_page(page)) + goto force_sigbus; + + page =3D compound_head(page); + + if (PageHuge(page)) { + walk.hugetlb_entry =3D hugetlb_range; + buff[0] =3D page_to_pfn(page); + } else if (PageTransHuge(page)) { + walk.pmd_entry =3D pmd_range; + buff[0] =3D (u64)page; + buff[1] =3D pfn; + } else { + walk.pte_entry =3D pte_range; + buff[0] =3D pfn; + } + + mmap_read_lock(p->mm); + ret =3D walk_page_range(p->mm, 0, TASK_SIZE_MAX, &walk, (void *)buff); + mmap_read_unlock(p->mm); + + pr_err("Memory error may not recovered: %#lx: Sending SIGBUS to %s:%d due= to hardware memory corruption\n", + pfn, p->comm, p->pid); + + if (ret) { + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)buff[0], buff[1]); + } else { +force_sigbus: + force_sig_mceerr(BUS_MCEERR_AR, (void __user *)0, PAGE_SHIFT); + } +} +EXPORT_SYMBOL_GPL(memory_failure_error); + #define MEMORY_FAILURE_FIFO_ORDER 4 #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER) =20 --=20 1.8.3.1