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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 370C5C38145 for ; Tue, 6 Sep 2022 19:01:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 97A486B0072; Tue, 6 Sep 2022 15:01:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9027D6B0073; Tue, 6 Sep 2022 15:01:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 756676B0074; Tue, 6 Sep 2022 15:01:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 649B16B0072 for ; Tue, 6 Sep 2022 15:01:00 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 317A3A080B for ; Tue, 6 Sep 2022 19:01:00 +0000 (UTC) X-FDA: 79882577880.10.CF33211 Received: from mail-io1-f47.google.com (mail-io1-f47.google.com [209.85.166.47]) by imf18.hostedemail.com (Postfix) with ESMTP id BFC4C1C0080 for ; Tue, 6 Sep 2022 19:00:59 +0000 (UTC) Received: by mail-io1-f47.google.com with SMTP id 62so9702597iov.5 for ; Tue, 06 Sep 2022 12:00:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date; bh=VZWfKkBjgWu+gLzzTMPZReTUPnxocF2s2gADqtxYuc4=; b=IJClkJZA2ci9X9YudNpotHQ2jHP9kri5ddYGJUdBbxArAYAFuAVNpwyi0s3x2GDssE wKlyoqG+UBUO81USH5es0irAMzX6EFRrghUs1JE+MnRT/e+EpqHnfVk4E9YlsCNYKSZR Xl/zBXPiLh9E3zBsrJo+zynSOWH0uE160CEF9eobQTk+DSbznkbFMDIZX6ryEvldAITQ rGd7A4QdHAe65SeKpekqDuZxrEzMMNC8Uh0XEMVhqGWbIum8wwMgpRB0uFJeatcHhbst 7ZYGUBjpSVmToOuJcW+bSV+1ks9AULpHqc28iGBCjEreYwuWq9VPoAmFhemRoaSqPBCN 1QYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date; bh=VZWfKkBjgWu+gLzzTMPZReTUPnxocF2s2gADqtxYuc4=; b=HJB8wSo2vrbya4g+FOwdpIHNraWhyJR6zYKEhd6QiV/H7AqnPQid6+093764m2NugP L1RAaxCG/p5dQiiZDQPlL/4VmbdeY+0vQCBgH51yoFXY5KTY72w6yfsYQLroapYdWqCF Et7HLM86GLIzTaqmLlUIijXPj7HknDr3ST3mQH+0xTswTVhfQd/yF+4092TZ0Trj1aer JkZrpvWGVDNNyaOs+Y5RBuMgBMwdfJKpRV1vEIAf8+Ruvx0Y2Jlca/+Qqz5eWQdqK3gp jiIUP7iPKc+nbewILpTwk5olRGo448ZTPYlRQ5qDdQiTVW8c43dJSinMEmIwdUTJjbtT zFwA== X-Gm-Message-State: ACgBeo1G2YRJkBV8w71FKPhCj6kaWQZaHg4PowUX5Ge7dGWaPe0AwYAU B38ne86YA0A+VG5lw6OdnVFhf4Mv3By16LTjJFmFWA== X-Google-Smtp-Source: AA6agR7xDh5HT5Y9eMResmshIM/DOvn/mOOq2ia7QJOQf/o2UTiVbl/Ns26hFBPH0Ki7mcr19c0jix+nJSfeWWZE0GE= X-Received: by 2002:a6b:2a88:0:b0:68a:e898:2822 with SMTP id q130-20020a6b2a88000000b0068ae8982822mr24499577ioq.75.1662490858786; Tue, 06 Sep 2022 12:00:58 -0700 (PDT) MIME-Version: 1.0 References: <20220901173516.702122-1-surenb@google.com> <20220901173516.702122-7-surenb@google.com> <1624be86-4c17-46e5-fafc-eb8afb7b9b4a@linux.ibm.com> In-Reply-To: <1624be86-4c17-46e5-fafc-eb8afb7b9b4a@linux.ibm.com> From: Suren Baghdasaryan Date: Tue, 6 Sep 2022 12:00:47 -0700 Message-ID: Subject: Re: [RFC PATCH RESEND 06/28] mm: mark VMA as locked whenever vma->vm_flags are modified To: Laurent Dufour Cc: Andrew Morton , Michel Lespinasse , Jerome Glisse , Michal Hocko , Vlastimil Babka , Johannes Weiner , Mel Gorman , Davidlohr Bueso , Matthew Wilcox , "Liam R. Howlett" , Peter Zijlstra , Laurent Dufour , "Paul E . McKenney" , Andy Lutomirski , Song Liu , Peter Xu , David Hildenbrand , dhowells@redhat.com, Hugh Dickins , Sebastian Andrzej Siewior , Kent Overstreet , David Rientjes , Axel Rasmussen , Joel Fernandes , Minchan Kim , kernel-team , linux-mm , linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=IJClkJZA; spf=pass (imf18.hostedemail.com: domain of surenb@google.com designates 209.85.166.47 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1662490859; a=rsa-sha256; cv=none; b=bex3ETLj0xMqgAdirtz4cmAZcPYBBhfPu1i5N5EPR5dMzOKQGmqAQNL9LfH+taujFPrA/X KTne9Gch+uKjplMMHj25Bftm6z3EfRCtPdBm+ZTXSSVqdlPHJBZ85VoODI32wRBduxVu4H mBxieKnKoTJlNQUUM1WGYAKk02b+IC4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1662490859; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VZWfKkBjgWu+gLzzTMPZReTUPnxocF2s2gADqtxYuc4=; b=z3/lzxSQ3Untp6TH7JYi+Dbg8i6tJJQLB+4kUmxE/kARjyQfuy2vLEISAZv8wNYNPlJKfu ekA3WzohjEwYlOkYBwZx889jIaCX5e8WdzToKCvj7rPPXMs+0bfIYPHe2CwflNqX5S7AYg CBqOfq2KlcK4MzJ+5zyjP1qsq6HnK1k= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: BFC4C1C0080 X-Rspam-User: Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=IJClkJZA; spf=pass (imf18.hostedemail.com: domain of surenb@google.com designates 209.85.166.47 as permitted sender) smtp.mailfrom=surenb@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: gc6gcowxjdtpijgsg9hzrecidad6t1cr X-HE-Tag: 1662490859-582442 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: On Tue, Sep 6, 2022 at 7:27 AM Laurent Dufour wrote= : > > Le 01/09/2022 =C3=A0 19:34, Suren Baghdasaryan a =C3=A9crit : > > VMA flag modifications should be done under VMA lock to prevent concurr= ent > > page fault handling in that area. > > > > Signed-off-by: Suren Baghdasaryan > > --- > > fs/proc/task_mmu.c | 1 + > > fs/userfaultfd.c | 6 ++++++ > > mm/madvise.c | 1 + > > mm/mlock.c | 2 ++ > > mm/mmap.c | 1 + > > mm/mprotect.c | 1 + > > 6 files changed, 12 insertions(+) > > There are few changes also done in the driver's space, for instance: > > *** arch/x86/kernel/cpu/sgx/driver.c: > sgx_mmap[98] vma->vm_flags |=3D VM_PFNMAP | VM_DONTEXPA= ND | > VM_DONTDUMP | VM_IO; > *** arch/x86/kernel/cpu/sgx/virt.c: > sgx_vepc_mmap[108] vma->vm_flags |=3D VM_PFNMAP | VM_IO | > VM_DONTDUMP | VM_DONTCOPY; > *** drivers/dax/device.c: > dax_mmap[311] vma->vm_flags |=3D VM_HUGEPAGE; > > I guess these changes to vm_flags should be protected as well, or to be > checked one by one. Thanks for noting these! I'll add necessary locking here and will look for other places I might have missed. > > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > index 4e0023643f8b..ceffa5c2c650 100644 > > --- a/fs/proc/task_mmu.c > > +++ b/fs/proc/task_mmu.c > > @@ -1285,6 +1285,7 @@ static ssize_t clear_refs_write(struct file *file= , const char __user *buf, > > for (vma =3D mm->mmap; vma; vma =3D vma->vm_next)= { > > if (!(vma->vm_flags & VM_SOFTDIRTY)) > > continue; > > + vma_mark_locked(vma); > > vma->vm_flags &=3D ~VM_SOFTDIRTY; > > vma_set_page_prot(vma); > > } > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > > index 175de70e3adf..fe557b3d1c07 100644 > > --- a/fs/userfaultfd.c > > +++ b/fs/userfaultfd.c > > @@ -620,6 +620,7 @@ static void userfaultfd_event_wait_completion(struc= t userfaultfd_ctx *ctx, > > mmap_write_lock(mm); > > for (vma =3D mm->mmap; vma; vma =3D vma->vm_next) > > if (vma->vm_userfaultfd_ctx.ctx =3D=3D release_ne= w_ctx) { > > + vma_mark_locked(vma); > > vma->vm_userfaultfd_ctx =3D NULL_VM_UFFD_= CTX; > > vma->vm_flags &=3D ~__VM_UFFD_FLAGS; > > } > > @@ -653,6 +654,7 @@ int dup_userfaultfd(struct vm_area_struct *vma, str= uct list_head *fcs) > > > > octx =3D vma->vm_userfaultfd_ctx.ctx; > > if (!octx || !(octx->features & UFFD_FEATURE_EVENT_FORK)) { > > + vma_mark_locked(vma); > > vma->vm_userfaultfd_ctx =3D NULL_VM_UFFD_CTX; > > vma->vm_flags &=3D ~__VM_UFFD_FLAGS; > > return 0; > > @@ -734,6 +736,7 @@ void mremap_userfaultfd_prep(struct vm_area_struct = *vma, > > atomic_inc(&ctx->mmap_changing); > > } else { > > /* Drop uffd context if remap feature not enabled */ > > + vma_mark_locked(vma); > > vma->vm_userfaultfd_ctx =3D NULL_VM_UFFD_CTX; > > vma->vm_flags &=3D ~__VM_UFFD_FLAGS; > > } > > @@ -891,6 +894,7 @@ static int userfaultfd_release(struct inode *inode,= struct file *file) > > vma =3D prev; > > else > > prev =3D vma; > > + vma_mark_locked(vma); > > vma->vm_flags =3D new_flags; > > vma->vm_userfaultfd_ctx =3D NULL_VM_UFFD_CTX; > > } > > @@ -1449,6 +1453,7 @@ static int userfaultfd_register(struct userfaultf= d_ctx *ctx, > > * the next vma was merged into the current one and > > * the current one has not been updated yet. > > */ > > + vma_mark_locked(vma); > > vma->vm_flags =3D new_flags; > > vma->vm_userfaultfd_ctx.ctx =3D ctx; > > > > @@ -1630,6 +1635,7 @@ static int userfaultfd_unregister(struct userfaul= tfd_ctx *ctx, > > * the next vma was merged into the current one and > > * the current one has not been updated yet. > > */ > > + vma_mark_locked(vma); > > vma->vm_flags =3D new_flags; > > vma->vm_userfaultfd_ctx =3D NULL_VM_UFFD_CTX; > > > > diff --git a/mm/madvise.c b/mm/madvise.c > > index 5f0f0948a50e..a173f0025abd 100644 > > --- a/mm/madvise.c > > +++ b/mm/madvise.c > > @@ -181,6 +181,7 @@ static int madvise_update_vma(struct vm_area_struct= *vma, > > /* > > * vm_flags is protected by the mmap_lock held in write mode. > > */ > > + vma_mark_locked(vma); > > vma->vm_flags =3D new_flags; > > if (!vma->vm_file) { > > error =3D replace_anon_vma_name(vma, anon_name); > > diff --git a/mm/mlock.c b/mm/mlock.c > > index b14e929084cc..f62e1a4d05f2 100644 > > --- a/mm/mlock.c > > +++ b/mm/mlock.c > > @@ -380,6 +380,7 @@ static void mlock_vma_pages_range(struct vm_area_st= ruct *vma, > > */ > > if (newflags & VM_LOCKED) > > newflags |=3D VM_IO; > > + vma_mark_locked(vma); > > WRITE_ONCE(vma->vm_flags, newflags); > > > > lru_add_drain(); > > @@ -456,6 +457,7 @@ static int mlock_fixup(struct vm_area_struct *vma, = struct vm_area_struct **prev, > > > > if ((newflags & VM_LOCKED) && (oldflags & VM_LOCKED)) { > > /* No work to do, and mlocking twice would be wrong */ > > + vma_mark_locked(vma); > > vma->vm_flags =3D newflags; > > } else { > > mlock_vma_pages_range(vma, start, end, newflags); > > diff --git a/mm/mmap.c b/mm/mmap.c > > index 693e6776be39..f89c9b058105 100644 > > --- a/mm/mmap.c > > +++ b/mm/mmap.c > > @@ -1818,6 +1818,7 @@ unsigned long mmap_region(struct file *file, unsi= gned long addr, > > out: > > perf_event_mmap(vma); > > > > + vma_mark_locked(vma); > > vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); > > if (vm_flags & VM_LOCKED) { > > if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || > > I guess, this doesn't really impact, but the call to vma_mark_locked(vma) > may be done only in the case the vm_flags field is touched. > Something like this: > > vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); > if (vm_flags & VM_LOCKED) { > if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || > is_vm_hugetlb_page(vma) || > - vma =3D=3D get_gate_vma(current->= mm)) > + vma =3D=3D get_gate_vma(current->= mm)) { > + vma_mark_locked(vma); > vma->vm_flags &=3D VM_LOCKED_CLEAR_MASK; > - else > + } else > mm->locked_vm +=3D (len >> PAGE_SHIFT); > } > > > > diff --git a/mm/mprotect.c b/mm/mprotect.c > > index bc6bddd156ca..df47fc21b0e4 100644 > > --- a/mm/mprotect.c > > +++ b/mm/mprotect.c > > @@ -621,6 +621,7 @@ mprotect_fixup(struct mmu_gather *tlb, struct vm_ar= ea_struct *vma, > > * vm_flags and vm_page_prot are protected by the mmap_lock > > * held in write mode. > > */ > > + vma_mark_locked(vma); > > vma->vm_flags =3D newflags; > > /* > > * We want to check manually if we can change individual PTEs wri= table >