From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 885A0C678DB for ; Thu, 19 Jan 2023 01:14:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229910AbjASBOy (ORCPT ); Wed, 18 Jan 2023 20:14:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229898AbjASBOE (ORCPT ); Wed, 18 Jan 2023 20:14:04 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4AC1268439 for ; Wed, 18 Jan 2023 17:13:55 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id F0904B81F6C for ; Thu, 19 Jan 2023 01:13:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96EF6C433EF; Thu, 19 Jan 2023 01:13:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1674090832; bh=sM7OwCTRKV7mw3zrEILWgTzjGTLrm2+cjmQ6Tav3CWw=; h=Date:To:From:Subject:From; b=mE6yGKLUhrjq4hZzKOv3iObcuqLxqpFBmlgYssUmjaU5GZ30GyFNIeHtn4f9Rf6Y3 GnUIJ6t6Vdw1Z0X1i9YDvMoYDu8XAnoMlR4a3FQUgsUn34X45CgYQp3leqizBJEtLv g9jlsCopc0bBhRhy5+u/sf2WCL4VSn6TUXXpwYbc= Date: Wed, 18 Jan 2023 17:13:52 -0800 To: mm-commits@vger.kernel.org, songmuchun@bytedance.com, riel@surriel.com, nadav.amit@gmail.com, mike.kravetz@oracle.com, linmiaohe@huawei.com, jthoughton@google.com, jhubbard@nvidia.com, jannh@google.com, david@redhat.com, aarcange@redhat.com, peterx@redhat.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare.patch removed from -mm tree Message-Id: <20230119011352.96EF6C433EF@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm/hugetlb: make userfaultfd_huge_must_wait() safe to pmd unshare has been removed from the -mm tree. Its filename was mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Peter Xu Subject: mm/hugetlb: make userfaultfd_huge_must_wait() safe to pmd unshare Date: Fri, 16 Dec 2022 10:52:17 -0500 We can take the hugetlb walker lock, here taking vma lock directly. Link: https://lkml.kernel.org/r/20221216155217.2043700-1-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: David Hildenbrand Reviewed-by: Mike Kravetz Reviewed-by: John Hubbard Cc: Andrea Arcangeli Cc: James Houghton Cc: Jann Horn Cc: Miaohe Lin Cc: Muchun Song Cc: Nadav Amit Cc: Rik van Riel Signed-off-by: Andrew Morton --- fs/userfaultfd.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) --- a/fs/userfaultfd.c~mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare +++ a/fs/userfaultfd.c @@ -391,7 +391,8 @@ static inline unsigned int userfaultfd_g */ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) { - struct mm_struct *mm = vmf->vma->vm_mm; + struct vm_area_struct *vma = vmf->vma; + struct mm_struct *mm = vma->vm_mm; struct userfaultfd_ctx *ctx; struct userfaultfd_wait_queue uwq; vm_fault_t ret = VM_FAULT_SIGBUS; @@ -418,7 +419,7 @@ vm_fault_t handle_userfault(struct vm_fa */ mmap_assert_locked(mm); - ctx = vmf->vma->vm_userfaultfd_ctx.ctx; + ctx = vma->vm_userfaultfd_ctx.ctx; if (!ctx) goto out; @@ -508,6 +509,15 @@ vm_fault_t handle_userfault(struct vm_fa blocking_state = userfaultfd_get_blocking_state(vmf->flags); + /* + * Take the vma lock now, in order to safely call + * userfaultfd_huge_must_wait() later. Since acquiring the + * (sleepable) vma lock can modify the current task state, that + * must be before explicitly calling set_current_state(). + */ + if (is_vm_hugetlb_page(vma)) + hugetlb_vma_lock_read(vma); + spin_lock_irq(&ctx->fault_pending_wqh.lock); /* * After the __add_wait_queue the uwq is visible to userland @@ -522,13 +532,15 @@ vm_fault_t handle_userfault(struct vm_fa set_current_state(blocking_state); spin_unlock_irq(&ctx->fault_pending_wqh.lock); - if (!is_vm_hugetlb_page(vmf->vma)) + if (!is_vm_hugetlb_page(vma)) must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags, reason); else - must_wait = userfaultfd_huge_must_wait(ctx, vmf->vma, + must_wait = userfaultfd_huge_must_wait(ctx, vma, vmf->address, vmf->flags, reason); + if (is_vm_hugetlb_page(vma)) + hugetlb_vma_unlock_read(vma); mmap_read_unlock(mm); if (likely(must_wait && !READ_ONCE(ctx->released))) { _ Patches currently in -mm which might be from peterx@redhat.com are selftests-vm-remove-__use_gnu-in-hugetlb-madvisec.patch