From patchwork Sun Apr 24 09:11:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12824825 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD430C433F5 for ; Sun, 24 Apr 2022 09:10:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C65FD6B0074; Sun, 24 Apr 2022 05:10:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C15086B0075; Sun, 24 Apr 2022 05:10:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AB73A6B007B; Sun, 24 Apr 2022 05:10:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 9AEC46B0074 for ; Sun, 24 Apr 2022 05:10:45 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 7874662B73 for ; Sun, 24 Apr 2022 09:10:45 +0000 (UTC) X-FDA: 79391202450.02.CEAE11B Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf03.hostedemail.com (Postfix) with ESMTP id EA27A2001F for ; Sun, 24 Apr 2022 09:10:41 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4KmMn330YbzhYT7; Sun, 24 Apr 2022 17:10:31 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sun, 24 Apr 2022 17:10:41 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH v3 1/3] mm/swapfile: unuse_pte can map random data if swap read fails Date: Sun, 24 Apr 2022 17:11:03 +0800 Message-ID: <20220424091105.48374-2-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220424091105.48374-1-linmiaohe@huawei.com> References: <20220424091105.48374-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Queue-Id: EA27A2001F X-Stat-Signature: f9ruhc4pr5ds54jofn4q8jtfdszx4awn X-Rspam-User: Authentication-Results: imf03.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf03.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-Rspamd-Server: rspam09 X-HE-Tag: 1650791441-201144 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: There is a bug in unuse_pte(): when swap page happens to be unreadable, page filled with random data is mapped into user address space. In case of error, a special swap entry indicating swap read fails is set to the page table. So the swapcache page can be freed and the user won't end up with a permanently mounted swap because a sector is bad. And if the page is accessed later, the user process will be killed so that corrupted data is never consumed. On the other hand, if the page is never accessed, the user won't even notice it. Signed-off-by: Miaohe Lin Acked-by: David Hildenbrand --- include/linux/swap.h | 7 ++++++- include/linux/swapops.h | 10 ++++++++++ mm/memory.c | 5 ++++- mm/swapfile.c | 11 +++++++++++ 4 files changed, 31 insertions(+), 2 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 5553189d0215..b82c196d8867 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -55,6 +55,10 @@ static inline int current_is_kswapd(void) * actions on faults. */ +#define SWP_SWAPIN_ERROR_NUM 1 +#define SWP_SWAPIN_ERROR (MAX_SWAPFILES + SWP_HWPOISON_NUM + \ + SWP_MIGRATION_NUM + SWP_DEVICE_NUM + \ + SWP_PTE_MARKER_NUM) /* * PTE markers are used to persist information onto PTEs that are mapped with * file-backed memories. As its name "PTE" hints, it should only be applied to @@ -120,7 +124,8 @@ static inline int current_is_kswapd(void) #define MAX_SWAPFILES \ ((1 << MAX_SWAPFILES_SHIFT) - SWP_DEVICE_NUM - \ - SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - SWP_PTE_MARKER_NUM) + SWP_MIGRATION_NUM - SWP_HWPOISON_NUM - \ + SWP_PTE_MARKER_NUM - SWP_SWAPIN_ERROR_NUM) /* * Magic header for a swap area. The first part of the union is diff --git a/include/linux/swapops.h b/include/linux/swapops.h index a291f210e7f8..9d989ed049a6 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -108,6 +108,16 @@ static inline void *swp_to_radix_entry(swp_entry_t entry) return xa_mk_value(entry.val); } +static inline swp_entry_t make_swapin_error_entry(struct page *page) +{ + return swp_entry(SWP_SWAPIN_ERROR, page_to_pfn(page)); +} + +static inline int is_swapin_error_entry(swp_entry_t entry) +{ + return swp_type(entry) == SWP_SWAPIN_ERROR; +} + #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) static inline swp_entry_t make_readable_device_private_entry(pgoff_t offset) { diff --git a/mm/memory.c b/mm/memory.c index f4161fb07ffa..626f63858e0c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1488,7 +1488,8 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, /* Only drop the uffd-wp marker if explicitly requested */ if (!zap_drop_file_uffd_wp(details)) continue; - } else if (is_hwpoison_entry(entry)) { + } else if (is_hwpoison_entry(entry) || + is_swapin_error_entry(entry)) { if (!should_zap_cows(details)) continue; } else { @@ -3728,6 +3729,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) ret = vmf->page->pgmap->ops->migrate_to_ram(vmf); } else if (is_hwpoison_entry(entry)) { ret = VM_FAULT_HWPOISON; + } else if (is_swapin_error_entry(entry)) { + ret = VM_FAULT_SIGBUS; } else if (is_pte_marker_entry(entry)) { ret = handle_pte_marker(vmf); } else { diff --git a/mm/swapfile.c b/mm/swapfile.c index 9398e915b36b..95b63f69f388 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, goto out; } + if (unlikely(!PageUptodate(page))) { + pte_t pteval; + + dec_mm_counter(vma->vm_mm, MM_SWAPENTS); + pteval = swp_entry_to_pte(make_swapin_error_entry(page)); + set_pte_at(vma->vm_mm, addr, pte, pteval); + swap_free(entry); + ret = 0; + goto out; + } + /* See do_swap_page() */ BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); BUG_ON(PageAnon(page) && PageAnonExclusive(page)); From patchwork Sun Apr 24 09:11:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12824827 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 79E3AC433EF for ; Sun, 24 Apr 2022 09:10:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9F6376B007B; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9CDA86B0078; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 894676B007E; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id 757C16B0078 for ; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 56FFE22805 for ; Sun, 24 Apr 2022 09:10:46 +0000 (UTC) X-FDA: 79391202492.13.2ECD9F0 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf27.hostedemail.com (Postfix) with ESMTP id 6F2D040035 for ; Sun, 24 Apr 2022 09:10:44 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KmMmJ41hYz1JBMN; Sun, 24 Apr 2022 17:09:52 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sun, 24 Apr 2022 17:10:41 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH v3 2/3] mm/swapfile: Fix lost swap bits in unuse_pte() Date: Sun, 24 Apr 2022 17:11:04 +0800 Message-ID: <20220424091105.48374-3-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220424091105.48374-1-linmiaohe@huawei.com> References: <20220424091105.48374-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Stat-Signature: x7ggbz4xppfiqmxose9gpzj8qst1zfw8 Authentication-Results: imf27.hostedemail.com; dkim=none; spf=pass (imf27.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6F2D040035 X-HE-Tag: 1650791444-481710 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: This is observed by code review only but not any real report. When we turn off swapping we could have lost the bits stored in the swap ptes. The new rmap-exclusive bit is fine since that turned into a page flag, but not for soft-dirty and uffd-wp. Add them. Suggested-by: Peter Xu Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand --- mm/swapfile.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 95b63f69f388..522a0eb16bf1 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1783,7 +1783,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, { struct page *swapcache; spinlock_t *ptl; - pte_t *pte; + pte_t *pte, new_pte; int ret = 1; swapcache = page; @@ -1832,8 +1832,12 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, page_add_new_anon_rmap(page, vma, addr); lru_cache_add_inactive_or_unevictable(page, vma); } - set_pte_at(vma->vm_mm, addr, pte, - pte_mkold(mk_pte(page, vma->vm_page_prot))); + new_pte = pte_mkold(mk_pte(page, vma->vm_page_prot)); + if (pte_swp_soft_dirty(*pte)) + new_pte = pte_mksoft_dirty(new_pte); + if (pte_swp_uffd_wp(*pte)) + new_pte = pte_mkuffd_wp(new_pte); + set_pte_at(vma->vm_mm, addr, pte, new_pte); swap_free(entry); out: pte_unmap_unlock(pte, ptl); From patchwork Sun Apr 24 09:11:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12824828 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 109E4C433F5 for ; Sun, 24 Apr 2022 09:10:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CAAB76B0078; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C437C6B0080; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 92F016B007D; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 8108F6B007B for ; Sun, 24 Apr 2022 05:10:46 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 5761822801 for ; Sun, 24 Apr 2022 09:10:46 +0000 (UTC) X-FDA: 79391202492.11.10EE51C Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf17.hostedemail.com (Postfix) with ESMTP id 9209440039 for ; Sun, 24 Apr 2022 09:10:40 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KmMmK2Q9zz1JBMP; Sun, 24 Apr 2022 17:09:53 +0800 (CST) Received: from huawei.com (10.175.124.27) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Sun, 24 Apr 2022 17:10:42 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH v3 3/3] mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range Date: Sun, 24 Apr 2022 17:11:05 +0800 Message-ID: <20220424091105.48374-4-linmiaohe@huawei.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20220424091105.48374-1-linmiaohe@huawei.com> References: <20220424091105.48374-1-linmiaohe@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 9209440039 X-Stat-Signature: 5zwkiqwj8ue9635toge9nxzsrs1hn4oh X-Rspam-User: Authentication-Results: imf17.hostedemail.com; dkim=none; spf=pass (imf17.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1650791440-535812 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: Once the MADV_FREE operation has succeeded, callers can expect they might get zero-fill pages if accessing the memory again. Therefore it should be safe to delete the hwpoison entry and swapin error entry. There is no reason to kill the process if it has called MADV_FREE on the range. Suggested-by: Alistair Popple Signed-off-by: Miaohe Lin Acked-by: David Hildenbrand Reviewed-by: Naoya Horiguchi --- mm/madvise.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 4d6592488b51..5f4537511532 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -624,11 +624,14 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr, swp_entry_t entry; entry = pte_to_swp_entry(ptent); - if (non_swap_entry(entry)) - continue; - nr_swap--; - free_swap_and_cache(entry); - pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); + if (!non_swap_entry(entry)) { + nr_swap--; + free_swap_and_cache(entry); + pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); + } else if (is_hwpoison_entry(entry) || + is_swapin_error_entry(entry)) { + pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); + } continue; }