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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v7-20020a17090a6b0700b002634d2ab01bsi2689819pjj.130.2023.06.29.19.07.53; Thu, 29 Jun 2023 19:08:08 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=DUV7BVM9; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232036AbjF3CFA (ORCPT + 99 others); Thu, 29 Jun 2023 22:05:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48658 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231937AbjF3CEt (ORCPT ); Thu, 29 Jun 2023 22:04:49 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 878121991 for ; Thu, 29 Jun 2023 19:04:47 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-5618857518dso11501237b3.2 for ; Thu, 29 Jun 2023 19:04:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1688090687; x=1690682687; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=V7p+xkeFpHpY+8imX6dpZwoTYVp943eibQ5qK+rLf3c=; b=DUV7BVM9nFkRrG4OmL2z1rbzNQPYA08eD/W6CM9ZTP8ycZScg2wT7L7+zDm47i3EEp YYXhyTKoKtmqRcvzOyTyV44bllZXd+7i1AMkEKCnp9VhDpEzAvKcS+2YEZK4NAZsYcoe y/bdw210HSJrZUvj1zbrUaU+YWomeS88ogbqihRlgl+T+b4TNg18Gr+BlED4NnaQkkkw f1IhR/XhDFUZ7ovgt4RYv6+3pQDpmsTR7as7++jPBwf7pFCGJ+iXgGbx70KDjUWJPZkG Jf9I49Iy4KlltuDt6TFCOy2p6d0dzZ9NTdp0L/acX6A4axhyfobo5rKVJIXrfSI6c/Al EGHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688090687; x=1690682687; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=V7p+xkeFpHpY+8imX6dpZwoTYVp943eibQ5qK+rLf3c=; b=VuCSm7+JV4DuTa7VpMq9CJpcLiQi5q2kvppXrPc5IA1sPtRLmsi02FUFxZuslvoh84 o2CCCW0qVz6mFbMfL7syPc/7a/aFBEtnf6bbtrOD534GkwsVV+E1IP2LBXdWwlXz7mrq vxGqHa5vz9O9uVsvj7TXhpnIiQomqgnjycZTtz6/r5mARcQJgVFvkx+CWxjeqxz/VstP CRH6kciIHuzkzte6hOPnRDeS6+QmhJyWROuyTzkzK2NDf839Eu4ozhzaIfVlHD41FdNe oCF/3XQFJKtfPrX6qSI6lWBtRtvOoatCnQOZVm9lMnqNpBVbln9w2SL60WrySxx90wpv vIxw== X-Gm-Message-State: ABy/qLbpcfrlIIhw+V0+wvi1btqVnolyWuU6cj97mqcdBqPfIvwtUqhN rX4MFSpSHS48O/y775vakmKbPpinYQQ= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:1f11:a3d0:19a9:16e5]) (user=surenb job=sendgmr) by 2002:a5b:a01:0:b0:c1d:d3e6:d52e with SMTP id k1-20020a5b0a01000000b00c1dd3e6d52emr10821ybq.0.1688090686807; Thu, 29 Jun 2023 19:04:46 -0700 (PDT) Date: Thu, 29 Jun 2023 19:04:32 -0700 In-Reply-To: <20230630020436.1066016-1-surenb@google.com> Mime-Version: 1.0 References: <20230630020436.1066016-1-surenb@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230630020436.1066016-4-surenb@google.com> Subject: [PATCH v6 3/6] mm: drop per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, hannes@cmpxchg.org, mhocko@suse.com, josef@toxicpanda.com, jack@suse.cz, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, michel@lespinasse.org, liam.howlett@oracle.com, jglisse@google.com, vbabka@suse.cz, minchan@google.com, dave@stgolabs.net, punit.agrawal@bytedance.com, lstoakes@gmail.com, hdanton@sina.com, apopple@nvidia.com, peterx@redhat.com, ying.huang@intel.com, david@redhat.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, pasha.tatashin@soleen.com, surenb@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1770091591843183381?= X-GMAIL-MSGID: =?utf-8?q?1770091591843183381?= handle_mm_fault returning VM_FAULT_RETRY or VM_FAULT_COMPLETED means mmap_lock has been released. However with per-VMA locks behavior is different and the caller should still release it. To make the rules consistent for the caller, drop the per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED. Currently the only path returning VM_FAULT_RETRY under per-VMA locks is do_swap_page and no path returns VM_FAULT_COMPLETED for now. Signed-off-by: Suren Baghdasaryan Acked-by: Peter Xu --- arch/arm64/mm/fault.c | 3 ++- arch/powerpc/mm/fault.c | 3 ++- arch/s390/mm/fault.c | 3 ++- arch/x86/mm/fault.c | 3 ++- mm/memory.c | 12 ++++++++++++ 5 files changed, 20 insertions(+), 4 deletions(-) diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 935f0a8911f9..9d78ff78b0e3 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -602,7 +602,8 @@ static int __kprobes do_page_fault(unsigned long far, unsigned long esr, goto lock_mmap; } fault = handle_mm_fault(vma, addr, mm_flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 5bfdf6ecfa96..82954d0e6906 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -489,7 +489,8 @@ static int ___do_page_fault(struct pt_regs *regs, unsigned long address, } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index dbe8394234e2..40a71063949b 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -418,7 +418,8 @@ static inline vm_fault_t do_exception(struct pt_regs *regs, int access) goto lock_mmap; } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); goto out; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index e8711b2cafaf..56b4f9faf8c4 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1341,7 +1341,8 @@ void do_user_addr_fault(struct pt_regs *regs, goto lock_mmap; } fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs); - vma_end_read(vma); + if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED))) + vma_end_read(vma); if (!(fault & VM_FAULT_RETRY)) { count_vm_vma_lock_event(VMA_LOCK_SUCCESS); diff --git a/mm/memory.c b/mm/memory.c index 0ae594703021..5f26c56ce979 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3730,6 +3730,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) if (vmf->flags & FAULT_FLAG_VMA_LOCK) { ret = VM_FAULT_RETRY; + vma_end_read(vma); goto out; } @@ -5182,6 +5183,17 @@ static vm_fault_t sanitize_fault_flags(struct vm_area_struct *vma, !is_cow_mapping(vma->vm_flags))) return VM_FAULT_SIGSEGV; } +#ifdef CONFIG_PER_VMA_LOCK + /* + * Per-VMA locks can't be used with FAULT_FLAG_RETRY_NOWAIT because of + * the assumption that lock is dropped on VM_FAULT_RETRY. + */ + if (WARN_ON_ONCE((*flags & + (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT)) == + (FAULT_FLAG_VMA_LOCK | FAULT_FLAG_RETRY_NOWAIT))) + return VM_FAULT_SIGSEGV; +#endif + return 0; }