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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 63799FB3CF5 for ; Mon, 30 Mar 2026 10:11:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CD8CF6B0099; Mon, 30 Mar 2026 06:11:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C88FA6B009B; Mon, 30 Mar 2026 06:11:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B783D6B009D; Mon, 30 Mar 2026 06:11:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id A5FF16B0099 for ; Mon, 30 Mar 2026 06:11:56 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 4B5FD140622 for ; Mon, 30 Mar 2026 10:11:56 +0000 (UTC) X-FDA: 84602313432.23.A1868E7 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf28.hostedemail.com (Postfix) with ESMTP id A4D38C0011 for ; Mon, 30 Mar 2026 10:11:54 +0000 (UTC) Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=J9PBouR4; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774865514; a=rsa-sha256; cv=none; b=QpyJshevf6w+scH0da7/uFtprar0xJACSHGHjU/GZePabaBokgObVaNHaa0Tv34VLqoyEL 3HFwT+O10vh2PGc5cb7S+JXPjHanTFVzyXMPcRSRHOYf0Z5bYGnrtahpir1W+BAytvMsGg LnugtVpOHN1tvDzlTBM69lKtKuabjKE= ARC-Authentication-Results: i=1; imf28.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=J9PBouR4; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf28.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774865514; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=g8J5DtXE4RT5GftJtmwhtOLDl4tKcn/SdloB4AIThyg=; b=1utBLlUTtZGww+dVhN1Ag1mJhqQmVQS/eqm4YtBilM2OrlNM7Zc27yNDwkas9/jMNZlmOS M+/uOsZQKsXA0tnSNAjm9vHfWy+S3SH/WPsmf2AxAUt18Tz4dzowy9MR0LLdVPeWB6gI6l MwNQU68H7jmFXiAP/GEnF1l6Vy+tfvo= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 1FBAF6011F; Mon, 30 Mar 2026 10:11:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9232FC2BCB5; Mon, 30 Mar 2026 10:11:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774865513; bh=ynjTmCe+1IWEv5uzQ9YDrK1M2CISmsrzcaIqVGmX5v0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J9PBouR46yBSGMp/xczSDwNBSz01ILMMSUj54LcWOXbIqNAWCWDiQOgfDL2mOpJeX jWmG3aMQSTYTPDkRqV982sQciqG5TEdyiaeAEcRpBwctsK1vNMR8kLvjmKH+OTaMh8 ZXPPiEZPMEfVIIMFDVu/qYHj/2MLKn7dwA3DEdchKRyf2i77SsBedtIGw2xcPwO4fw YgMb4eBrNILU5qOsa8Au+P2E4ooFL2zy8mIGhp+S7Anm6rAiRfKpcXiCw8L/gYdBge Ata/+5uKD1wBFajLa+AtZtMH42pL7iE6FbyBqGi+1qfJDSK3Z0NwCVZnovq4SmH0T7 KWc50FhDtW59A== From: Mike Rapoport To: Andrew Morton Cc: Andrea Arcangeli , Andrei Vagin , Axel Rasmussen , Baolin Wang , David Hildenbrand , Harry Yoo , Hugh Dickins , James Houghton , "Liam R. Howlett" , "Lorenzo Stoakes (Oracle)" , "Matthew Wilcox (Oracle)" , Michal Hocko , Mike Rapoport , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v3 04/15] userfaultfd: introduce mfill_get_vma() and mfill_put_vma() Date: Mon, 30 Mar 2026 13:11:05 +0300 Message-ID: <20260330101116.1117699-5-rppt@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260330101116.1117699-1-rppt@kernel.org> References: <20260330101116.1117699-1-rppt@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: A4D38C0011 X-Stat-Signature: skbwszusyju3hy77utt9r6tuaiq4hf9q X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1774865514-876651 X-HE-Meta: U2FsdGVkX1/9tWhvegtWbeXJ0h7mXS8k316muuiR7NYtqS/g3Q9utIM1y5/kBOrZZ3ythHUQhRYUyTGa61PgwK6A/tTfEit30SqzxPQiACK0y9tNd2WHfBbYZiYNVHJlnGuLyKTR+yb0XxCM+A1WRxnoF4+fx+27UX1E0W1Uuu7WiDGznMFvFSppcy3suKV0eKsKyMQ6vsiX8yvqQTvy+DyxtE3z8K2j704H+ttzuH0qNi9iLnUe+foPzBVBX8PUeMNR5xIiC2Xh870JsUg6+O77Z5dwcAlZ6tsGhKM8qlpMdLd3i7XcgRKnO5vPK+bpekriG1sON+86Ytc5w2WpuC8QEYqGpR9nDcWLl4X0Je921OwwRgp/ru9ePTHs/0JiIfpz52rqm1lluDtp+8oywfJc/prtI1wNfB2jV39OUUriYLILbckb20dJf1yGxsrj1USpaaO9KcsCKrQw4wYBOLAtEOnWHRjk7MS5pTV95hamElK2S28eZnUqtemRTCLUoavHKipjWE82a1QwPiov+yb2HB82+/qMvLvQnCqECdeE0mnHb+RMT4aZht6vVDAYpP5F9WabNfUB4ikMeqv7JLqMVKHSVJb08rhFHu7OTr6p0SOfVFRNqQCwF8qB3j48I93+Bkj6z3s5I/n8NUj+gFcITDb4Y7yGcl/dBsyR2L2gHjm/P93TbNCq7I93XY4LCiLfftkPbDdpXHTf/BCOcZSYWgZq7YKgf4OWEnyf4tD0soAiBV7jd0pcXkeCJaKVCleMGHbAMZYUYgGAokOpymI0Q/8WS9fyoMpWSP7adP0qkmEZf9u64u9GDFI4u6l7W9qRfm2zT1yUEwwDyzI1L2JFqKT3nz/ZHZgj55vAau0sSAOfZGx0XWT9m35oCFWKOZuZJP9/GNeXo5b7Qq4ZUEkuFpLOl9Kp70hwPemIgg8XLFuuhKhv9GLlxsQbKPrlUDdKHwsNZSWBL2BSwWc OKkVj21g 7bQWQUoru2fzXCHurGkkzzwVLbaI95eJjB1FDTqv+ioME7S4YacvxE2qZSkHeWr428SCTylbXx8cRCbspJpNKOv2r3C2RCxoHlQUEAYelsDVOw/pLiq5rBRPGCWgi8bP9oTwmBjf8wi/PBGuaTcMBmHsTU6L3deMhoJuSrWaRc+I1YGOBPJ9DkcQn0ikUMsgyS+bc/gs6T6nXAcRZKQX1opNUuuvimNML2udN3jJrC6G/qdDD+Xgl51GKPlSOkYhlpe9WOa/bjOWfn14fqmT6itgvM4EdjkfKsYNp9Bzray+shOI= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: "Mike Rapoport (Microsoft)" Split the code that finds, locks and verifies VMA from mfill_atomic() into a helper function. This function will be used later during refactoring of mfill_atomic_pte_copy(). Add a counterpart mfill_put_vma() helper that unlocks the VMA and releases map_changing_lock. [avagin@google.com: fix lock leak in mfill_get_vma()] Link: https://lkml.kernel.org/r/20260316173829.1126728-1-avagin@google.com Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Andrei Vagin --- mm/userfaultfd.c | 126 ++++++++++++++++++++++++++++------------------- 1 file changed, 75 insertions(+), 51 deletions(-) diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 291e5cfed431..c6a38db45343 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -157,6 +157,75 @@ static void uffd_mfill_unlock(struct vm_area_struct *vma) } #endif +static void mfill_put_vma(struct mfill_state *state) +{ + if (!state->vma) + return; + + up_read(&state->ctx->map_changing_lock); + uffd_mfill_unlock(state->vma); + state->vma = NULL; +} + +static int mfill_get_vma(struct mfill_state *state) +{ + struct userfaultfd_ctx *ctx = state->ctx; + uffd_flags_t flags = state->flags; + struct vm_area_struct *dst_vma; + int err; + + /* + * Make sure the vma is not shared, that the dst range is + * both valid and fully within a single existing vma. + */ + dst_vma = uffd_mfill_lock(ctx->mm, state->dst_start, state->len); + if (IS_ERR(dst_vma)) + return PTR_ERR(dst_vma); + + /* + * If memory mappings are changing because of non-cooperative + * operation (e.g. mremap) running in parallel, bail out and + * request the user to retry later + */ + down_read(&ctx->map_changing_lock); + state->vma = dst_vma; + err = -EAGAIN; + if (atomic_read(&ctx->mmap_changing)) + goto out_unlock; + + err = -EINVAL; + + /* + * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but + * it will overwrite vm_ops, so vma_is_anonymous must return false. + */ + if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) && + dst_vma->vm_flags & VM_SHARED)) + goto out_unlock; + + /* + * validate 'mode' now that we know the dst_vma: don't allow + * a wrprotect copy if the userfaultfd didn't register as WP. + */ + if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP)) + goto out_unlock; + + if (is_vm_hugetlb_page(dst_vma)) + return 0; + + if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) + goto out_unlock; + if (!vma_is_shmem(dst_vma) && + uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE)) + goto out_unlock; + + return 0; + +out_unlock: + mfill_put_vma(state); + return err; +} + static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address) { pgd_t *pgd; @@ -767,8 +836,6 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, .src_addr = src_start, .dst_addr = dst_start, }; - struct mm_struct *dst_mm = ctx->mm; - struct vm_area_struct *dst_vma; long copied = 0; ssize_t err; @@ -783,57 +850,17 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, VM_WARN_ON_ONCE(dst_start + len <= dst_start); retry: - /* - * Make sure the vma is not shared, that the dst range is - * both valid and fully within a single existing vma. - */ - dst_vma = uffd_mfill_lock(dst_mm, dst_start, len); - if (IS_ERR(dst_vma)) { - err = PTR_ERR(dst_vma); + err = mfill_get_vma(&state); + if (err) goto out; - } - - /* - * If memory mappings are changing because of non-cooperative - * operation (e.g. mremap) running in parallel, bail out and - * request the user to retry later - */ - down_read(&ctx->map_changing_lock); - err = -EAGAIN; - if (atomic_read(&ctx->mmap_changing)) - goto out_unlock; - - err = -EINVAL; - /* - * shmem_zero_setup is invoked in mmap for MAP_ANONYMOUS|MAP_SHARED but - * it will overwrite vm_ops, so vma_is_anonymous must return false. - */ - if (WARN_ON_ONCE(vma_is_anonymous(dst_vma) && - dst_vma->vm_flags & VM_SHARED)) - goto out_unlock; - - /* - * validate 'mode' now that we know the dst_vma: don't allow - * a wrprotect copy if the userfaultfd didn't register as WP. - */ - if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP)) - goto out_unlock; /* * If this is a HUGETLB vma, pass off to appropriate routine */ - if (is_vm_hugetlb_page(dst_vma)) - return mfill_atomic_hugetlb(ctx, dst_vma, dst_start, + if (is_vm_hugetlb_page(state.vma)) + return mfill_atomic_hugetlb(ctx, state.vma, dst_start, src_start, len, flags); - if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma)) - goto out_unlock; - if (!vma_is_shmem(dst_vma) && - uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE)) - goto out_unlock; - - state.vma = dst_vma; - while (state.src_addr < src_start + len) { VM_WARN_ON_ONCE(state.dst_addr >= dst_start + len); @@ -852,8 +879,7 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, if (unlikely(err == -ENOENT)) { void *kaddr; - up_read(&ctx->map_changing_lock); - uffd_mfill_unlock(state.vma); + mfill_put_vma(&state); VM_WARN_ON_ONCE(!state.folio); kaddr = kmap_local_folio(state.folio, 0); @@ -882,9 +908,7 @@ static __always_inline ssize_t mfill_atomic(struct userfaultfd_ctx *ctx, break; } -out_unlock: - up_read(&ctx->map_changing_lock); - uffd_mfill_unlock(state.vma); + mfill_put_vma(&state); out: if (state.folio) folio_put(state.folio); -- 2.53.0