From patchwork Mon Oct 31 20:10:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 1697474 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=eb21XHvT; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4N1PSs6Hjtz23lC for ; Tue, 1 Nov 2022 07:12:13 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4N1PSs5Qftz3c6k for ; Tue, 1 Nov 2022 07:12:13 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=eb21XHvT; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=intel.com (client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=tony.luck@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=eb21XHvT; dkim-atps=neutral Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4N1PRS5zjfz30NS for ; Tue, 1 Nov 2022 07:11:00 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667247061; x=1698783061; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=FkjXs29rqfDyvtsYyleWaTFa4Yy2vHuQ4WNYRV8TNe0=; b=eb21XHvTOSi37RmhMPCEdmiQlS0Z1SBMRUbXx+vAsbx58x807rEJo6wG BhTLpxmcNRz8dbMMZamLSJc9tr7RHUM7PPs+KBr0XFD5lXwUxsZHLyE5O z8IRlPU6mQnJ/8GQ2P4EWNFQK1DJvPgN2YD7VZjZYHYnCP4ghxKeawTv8 7ORMLMheugAqf81DmpIvGZdWGnge4ISE8B68azA100FoPxjv55qBjjL7p XAMQJdz7jc7H5B7RYrGQNvZ+Lzo/qfCogs3g6+G41w+mXuqjQVft5hZwN j1NRzojovTv3muKdJiSoktKtlQwNt3MAdJbC3skcOrtDl7Nc7ME7FVsbK Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10517"; a="296408520" X-IronPort-AV: E=Sophos;i="5.95,228,1661842800"; d="scan'208";a="296408520" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2022 13:10:47 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10517"; a="722931443" X-IronPort-AV: E=Sophos;i="5.95,228,1661842800"; d="scan'208";a="722931443" Received: from agluck-desk3.sc.intel.com ([172.25.222.78]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2022 13:10:47 -0700 From: Tony Luck To: Andrew Morton Subject: [PATCH v4 1/2] mm, hwpoison: Try to recover from copy-on write faults Date: Mon, 31 Oct 2022 13:10:28 -0700 Message-Id: <20221031201029.102123-2-tony.luck@intel.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221031201029.102123-1-tony.luck@intel.com> References: <20221021200120.175753-1-tony.luck@intel.com> <20221031201029.102123-1-tony.luck@intel.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Miaohe Lin , Tony Luck , Naoya Horiguchi , linux-kernel@vger.kernel.org, Matthew Wilcox , linux-mm@kvack.org, Alexander Potapenko , Shuai Xue , Nicholas Piggin , Dan Williams , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" If the kernel is copying a page as the result of a copy-on-write fault and runs into an uncorrectable error, Linux will crash because it does not have recovery code for this case where poison is consumed by the kernel. It is easy to set up a test case. Just inject an error into a private page, fork(2), and have the child process write to the page. I wrapped that neatly into a test at: git://git.kernel.org/pub/scm/linux/kernel/git/aegl/ras-tools.git just enable ACPI error injection and run: # ./einj_mem-uc -f copy-on-write Add a new copy_user_highpage_mc() function that uses copy_mc_to_kernel() on architectures where that is available (currently x86 and powerpc). When an error is detected during the page copy, return VM_FAULT_HWPOISON to caller of wp_page_copy(). This propagates up the call stack. Both x86 and powerpc have code in their fault handler to deal with this code by sending a SIGBUS to the application. Note that this patch avoids a system crash and signals the process that triggered the copy-on-write action. It does not take any action for the memory error that is still in the shared page. To handle that a call to memory_failure() is needed. But this cannot be done from wp_page_copy() because it holds mmap_lock(). Perhaps the architecture fault handlers can deal with this loose end in a subsequent patch? On Intel/x86 this loose end will often be handled automatically because the memory controller provides an additional notification of the h/w poison in memory, the handler for this will call memory_failure(). This isn't a 100% solution. If there are multiple errors, not all may be logged in this way. Reviewed-by: Dan Williams Reviewed-by: Miaohe Lin Reviewed-by: Naoya Horiguchi Tested-by: Shuai Xue Signed-off-by: Tony Luck Message-Id: <20221021200120.175753-2-tony.luck@intel.com> Signed-off-by: Tony Luck --- include/linux/highmem.h | 26 ++++++++++++++++++++++++++ mm/memory.c | 30 ++++++++++++++++++++---------- 2 files changed, 46 insertions(+), 10 deletions(-) diff --git a/include/linux/highmem.h b/include/linux/highmem.h index e9912da5441b..44242268f53b 100644 --- a/include/linux/highmem.h +++ b/include/linux/highmem.h @@ -319,6 +319,32 @@ static inline void copy_user_highpage(struct page *to, struct page *from, #endif +#ifdef copy_mc_to_kernel +static inline int copy_mc_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma) +{ + unsigned long ret; + char *vfrom, *vto; + + vfrom = kmap_local_page(from); + vto = kmap_local_page(to); + ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE); + if (!ret) + kmsan_unpoison_memory(page_address(to), PAGE_SIZE); + kunmap_local(vto); + kunmap_local(vfrom); + + return ret; +} +#else +static inline int copy_mc_user_highpage(struct page *to, struct page *from, + unsigned long vaddr, struct vm_area_struct *vma) +{ + copy_user_highpage(to, from, vaddr, vma); + return 0; +} +#endif + #ifndef __HAVE_ARCH_COPY_HIGHPAGE static inline void copy_highpage(struct page *to, struct page *from) diff --git a/mm/memory.c b/mm/memory.c index f88c351aecd4..b6056eef2f72 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2848,10 +2848,16 @@ static inline int pte_unmap_same(struct vm_fault *vmf) return same; } -static inline bool __wp_page_copy_user(struct page *dst, struct page *src, - struct vm_fault *vmf) +/* + * Return: + * 0: copied succeeded + * -EHWPOISON: copy failed due to hwpoison in source page + * -EAGAIN: copied failed (some other reason) + */ +static inline int __wp_page_copy_user(struct page *dst, struct page *src, + struct vm_fault *vmf) { - bool ret; + int ret; void *kaddr; void __user *uaddr; bool locked = false; @@ -2860,8 +2866,9 @@ static inline bool __wp_page_copy_user(struct page *dst, struct page *src, unsigned long addr = vmf->address; if (likely(src)) { - copy_user_highpage(dst, src, addr, vma); - return true; + if (copy_mc_user_highpage(dst, src, addr, vma)) + return -EHWPOISON; + return 0; } /* @@ -2888,7 +2895,7 @@ static inline bool __wp_page_copy_user(struct page *dst, struct page *src, * and update local tlb only */ update_mmu_tlb(vma, addr, vmf->pte); - ret = false; + ret = -EAGAIN; goto pte_unlock; } @@ -2913,7 +2920,7 @@ static inline bool __wp_page_copy_user(struct page *dst, struct page *src, if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) { /* The PTE changed under us, update local tlb */ update_mmu_tlb(vma, addr, vmf->pte); - ret = false; + ret = -EAGAIN; goto pte_unlock; } @@ -2932,7 +2939,7 @@ static inline bool __wp_page_copy_user(struct page *dst, struct page *src, } } - ret = true; + ret = 0; pte_unlock: if (locked) @@ -3104,6 +3111,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) pte_t entry; int page_copied = 0; struct mmu_notifier_range range; + int ret; delayacct_wpcopy_start(); @@ -3121,19 +3129,21 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) if (!new_page) goto oom; - if (!__wp_page_copy_user(new_page, old_page, vmf)) { + ret = __wp_page_copy_user(new_page, old_page, vmf); + if (ret) { /* * COW failed, if the fault was solved by other, * it's fine. If not, userspace would re-fault on * the same address and we will handle the fault * from the second attempt. + * The -EHWPOISON case will not be retried. */ put_page(new_page); if (old_page) put_page(old_page); delayacct_wpcopy_end(); - return 0; + return ret == -EHWPOISON ? VM_FAULT_HWPOISON : 0; } kmsan_copy_page_meta(new_page, old_page); } From patchwork Mon Oct 31 20:10:29 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 1697475 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=2404:9400:2:0:216:3eff:fee1:b9f1; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=dN+2m2qU; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2404:9400:2:0:216:3eff:fee1:b9f1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-384)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4N1PTt3zVyz23lC for ; Tue, 1 Nov 2022 07:13:06 +1100 (AEDT) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4N1PTs6kkVz3cd2 for ; Tue, 1 Nov 2022 07:13:05 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=dN+2m2qU; dkim-atps=neutral X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=intel.com (client-ip=134.134.136.20; helo=mga02.intel.com; envelope-from=tony.luck@intel.com; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=dN+2m2qU; dkim-atps=neutral Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4N1PRV5D3Sz30NS for ; Tue, 1 Nov 2022 07:11:02 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1667247062; x=1698783062; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=/v2ZvqyUX9QuQjryssW2yaZzhbAsEUWDkNYvgzcoQls=; b=dN+2m2qUi/CbwKUW3aHuF+QIhRyDdq7ayinOigzuzfjNpOP+Nv47OZZ1 M0O8DpFsLWqzKTFZaatbRNTIW1QiQ/Vm3zjm3OaZtrcyx92CM8xfUosZj CnhWRfpcY/tRLTlTHT8tl2Hhtmjud6pW87WSy9oW/egASV33IVPnluIn6 unDiK6ZO5D3Ahg3tCGzJAGStoFJ7rrc4mvnfvxpZsECEVGPaDdSsr320G L4hHDXxJbkoBJ1dkvINIF0OPIngRzYi6uSW2wQpfzWRob9e2wgIbzzXsR GhTY6zQ5g7HolRY+pN06AllADyT1mHG7um/LWtWoHhuWk5EVJFaabiO6r Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10517"; a="296408521" X-IronPort-AV: E=Sophos;i="5.95,228,1661842800"; d="scan'208";a="296408521" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2022 13:10:47 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10517"; a="722931446" X-IronPort-AV: E=Sophos;i="5.95,228,1661842800"; d="scan'208";a="722931446" Received: from agluck-desk3.sc.intel.com ([172.25.222.78]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 Oct 2022 13:10:47 -0700 From: Tony Luck To: Andrew Morton Subject: [PATCH v4 2/2] mm, hwpoison: When copy-on-write hits poison, take page offline Date: Mon, 31 Oct 2022 13:10:29 -0700 Message-Id: <20221031201029.102123-3-tony.luck@intel.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221031201029.102123-1-tony.luck@intel.com> References: <20221021200120.175753-1-tony.luck@intel.com> <20221031201029.102123-1-tony.luck@intel.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Miaohe Lin , Tony Luck , Naoya Horiguchi , linux-kernel@vger.kernel.org, Matthew Wilcox , linux-mm@kvack.org, Alexander Potapenko , Shuai Xue , Nicholas Piggin , Dan Williams , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Cannot call memory_failure() directly from the fault handler because mmap_lock (and others) are held. It is important, but not urgent, to mark the source page as h/w poisoned and unmap it from other tasks. Use memory_failure_queue() to request a call to memory_failure() for the page with the error. Also provide a stub version for CONFIG_MEMORY_FAILURE=n Reviewed-by: Miaohe Lin Tested-by: Shuai Xue Signed-off-by: Tony Luck Message-Id: <20221021200120.175753-3-tony.luck@intel.com> Signed-off-by: Tony Luck --- include/linux/mm.h | 5 ++++- mm/memory.c | 4 +++- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 8bbcccbc5565..03ced659eb58 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3268,7 +3268,6 @@ enum mf_flags { int mf_dax_kill_procs(struct address_space *mapping, pgoff_t index, unsigned long count, int mf_flags); extern int memory_failure(unsigned long pfn, int flags); -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); extern int sysctl_memory_failure_early_kill; @@ -3277,8 +3276,12 @@ extern void shake_page(struct page *p); extern atomic_long_t num_poisoned_pages __read_mostly; extern int soft_offline_page(unsigned long pfn, int flags); #ifdef CONFIG_MEMORY_FAILURE +extern void memory_failure_queue(unsigned long pfn, int flags); extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags); #else +static inline void memory_failure_queue(unsigned long pfn, int flags) +{ +} static inline int __get_huge_page_for_hwpoison(unsigned long pfn, int flags) { return 0; diff --git a/mm/memory.c b/mm/memory.c index b6056eef2f72..eae242351726 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2866,8 +2866,10 @@ static inline int __wp_page_copy_user(struct page *dst, struct page *src, unsigned long addr = vmf->address; if (likely(src)) { - if (copy_mc_user_highpage(dst, src, addr, vma)) + if (copy_mc_user_highpage(dst, src, addr, vma)) { + memory_failure_queue(page_to_pfn(src), 0); return -EHWPOISON; + } return 0; }