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 3214C106F2FB for ; Thu, 26 Mar 2026 08:08:50 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 651346B0092; Thu, 26 Mar 2026 04:08:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 628BA6B0093; Thu, 26 Mar 2026 04:08:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 53F086B0095; Thu, 26 Mar 2026 04:08:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 368056B0092 for ; Thu, 26 Mar 2026 04:08:49 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 040F55C701 for ; Thu, 26 Mar 2026 08:08:48 +0000 (UTC) X-FDA: 84587487978.20.D172371 Received: from mail-dy1-f201.google.com (mail-dy1-f201.google.com [74.125.82.201]) by imf09.hostedemail.com (Postfix) with ESMTP id 3DC9A140002 for ; Thu, 26 Mar 2026 08:08:47 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=RrVVZc1y; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf09.hostedemail.com: domain of 3jenEaQYKCMg685s1pu22uzs.q20zw18B-00y9oqy.25u@flex--surenb.bounces.google.com designates 74.125.82.201 as permitted sender) smtp.mailfrom=3jenEaQYKCMg685s1pu22uzs.q20zw18B-00y9oqy.25u@flex--surenb.bounces.google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774512527; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=C+yXmhx3uKy+6G9q4kJM+us9QDWjdFJDAOgDq56Y4dE=; b=PfIwZiR+g4fGIJUkQKkRI1EaVl4HjchYLlP52Dgeikz91aCxsdtqvlWaaYtrEMkxyaYNlv dpIJY7EfjnBHXl49xnvfgEQsPGDq8h1DLGXUeHBBUYvfGn8Wd4N58uHCC6zeHdNzGnpiny ulqC3GrlZk/Knrll57+/usyUgo1Oe7s= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774512527; a=rsa-sha256; cv=none; b=A8AtG+1L/aYhDJeOndDokoBM9iwymfLzUqrtEZC2SF1lfvk0xB+U3VLELNjlpobihj3feB UgS9ZYJ7XTLOr6+S/8X31dYX1yzsjfZWAn+1230uPwy8G3yzHKDYpNBmRCaOgIzMcr88aQ t2fMXpNdhnCFvygMGnxtHnQ2y7Tijlc= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=RrVVZc1y; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf09.hostedemail.com: domain of 3jenEaQYKCMg685s1pu22uzs.q20zw18B-00y9oqy.25u@flex--surenb.bounces.google.com designates 74.125.82.201 as permitted sender) smtp.mailfrom=3jenEaQYKCMg685s1pu22uzs.q20zw18B-00y9oqy.25u@flex--surenb.bounces.google.com Received: by mail-dy1-f201.google.com with SMTP id 5a478bee46e88-2c0ffce2570so4640865eec.1 for ; Thu, 26 Mar 2026 01:08:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1774512526; x=1775117326; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=C+yXmhx3uKy+6G9q4kJM+us9QDWjdFJDAOgDq56Y4dE=; b=RrVVZc1ycPDI2TQddsptjuwOJmHaK2r6v0CxQhXSEOmFaIlHjzYmSxxxfmSQZFl4Y4 NGsS0cM0xR2f4OzUEuvkDBwLO6Ggovo5vycd8jZHfCurKxEd8+cz9/RmbhWoIVTGG6RA eJZTZsAMvfXGS6862vILoLD+G7y5XEl9LLK2l5ugvdUbU816wa3V43nIp4l0NAWIAb2z hf8ZlR6w0jvwmEsCn2xhiMm3sQlJoSTommFbJdJtLc5OPZccRPvgClVL1QlvICdD6rOj 7PJjLVK3NI16ie9ZPq9ml6v+oYlOVm18RQ8lk+rQ2Zk8kJT/SeQMAUlSmt0D8g/8vu71 hsbw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774512526; x=1775117326; 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=C+yXmhx3uKy+6G9q4kJM+us9QDWjdFJDAOgDq56Y4dE=; b=pWh9y5EoPxHJuJJIYXdG+icTrdONUf9KKWPhx9GRhRaaf1z23zdAPDYTeADC/NiEbP hkW/6aaoEsps4s5Yp11/eyESmra7OEg3VgvldRdhYQZX3190xZGXuPuFH5D/6WzvgZ6G i7eiqwsoh5f3iWAX5++YcEUyTk1ZJ2DCu+ZTCONe3huXmD+nByFVhAymAyPRg0XuC2Uj wNFJolMCzZ3aecPKqThW9tSDmpvxdUZzOutym+y6bL5ZsJKS7vizBGeyoYs/XplqE6wi VU6ywF3S9m6kjepWrxiOJ455igTA5SI5oCv1UsreMBcG9o/eVkmdFD3exBfGIaE1D0tg /TfQ== X-Forwarded-Encrypted: i=1; AJvYcCVEmOqLVyp4XQEYQIdJJHRPJiTzaNEv7qbRtx2Ic8hCvi4Dn76zcDiUKR8uxmxlGHTjS6FUyajXTA==@kvack.org X-Gm-Message-State: AOJu0YwO0gd4Lu6URuhNwapga8vDKSsmCEEJ/0jEcx3YF9c0GkVo7fyY sM2Wi831ZELNVd5EfmYPG5hfOyO8dsKWeyfs6kNwXn+L02Jpp9kPZRjGbfQ11JMc3u59CStx0NV LHLIGMA== X-Received: from dlbvs2.prod.google.com ([2002:a05:7022:3f02:b0:128:d36e:eb6f]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:402:b0:11b:c1ab:bdd4 with SMTP id a92af1059eb24-12a96f04f69mr3338876c88.38.1774512525642; Thu, 26 Mar 2026 01:08:45 -0700 (PDT) Date: Thu, 26 Mar 2026 01:08:32 -0700 In-Reply-To: <20260326080836.695207-1-surenb@google.com> Mime-Version: 1.0 References: <20260326080836.695207-1-surenb@google.com> X-Mailer: git-send-email 2.53.0.1018.g2bb0e51243-goog Message-ID: <20260326080836.695207-3-surenb@google.com> Subject: [PATCH v5 2/6] mm: use vma_start_write_killable() in mm syscalls From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, david@kernel.org, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, gourry@gourry.net, ying.huang@linux.alibaba.com, apopple@nvidia.com, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, vbabka@suse.cz, jannh@google.com, rppt@kernel.org, mhocko@suse.com, pfalcato@suse.de, kees@kernel.org, maddy@linux.ibm.com, npiggin@gmail.com, mpe@ellerman.id.au, chleroy@kernel.org, borntraeger@linux.ibm.com, frankja@linux.ibm.com, imbrenda@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com, gerald.schaefer@linux.ibm.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, surenb@google.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 3DC9A140002 X-Stat-Signature: 5y94de7tsktcz9tiw33ijs4iio9a5kah X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1774512526-679359 X-HE-Meta: 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 NUNtZyu5 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Replace vma_start_write() with vma_start_write_killable() in syscalls, improving reaction time to the kill signal. In a number of places we now lock VMA earlier than before to avoid doing work and undoing it later if a fatal signal is pending. This is safe because the moves are happening within sections where we already hold the mmap_write_lock, so the moves do not change the locking order relative to other kernel locks. Suggested-by: Matthew Wilcox Signed-off-by: Suren Baghdasaryan --- mm/madvise.c | 4 +++- mm/memory.c | 2 ++ mm/mempolicy.c | 11 +++++++++-- mm/mlock.c | 28 ++++++++++++++++++++++------ mm/mprotect.c | 5 ++++- mm/mremap.c | 8 +++++--- mm/mseal.c | 5 ++++- 7 files changed, 49 insertions(+), 14 deletions(-) diff --git a/mm/madvise.c b/mm/madvise.c index 69708e953cf5..feaa16b0e1dc 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -175,7 +175,9 @@ static int madvise_update_vma(vm_flags_t new_flags, madv_behavior->vma = vma; /* vm_flags is protected by the mmap_lock held in write mode. */ - vma_start_write(vma); + if (vma_start_write_killable(vma)) + return -EINTR; + vma->flags = new_vma_flags; if (set_new_anon_name) return replace_anon_vma_name(vma, anon_name); diff --git a/mm/memory.c b/mm/memory.c index e44469f9cf65..9f99ec634831 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -366,6 +366,8 @@ void free_pgd_range(struct mmu_gather *tlb, * page tables that should be removed. This can differ from the vma mappings on * some archs that may have mappings that need to be removed outside the vmas. * Note that the prev->vm_end and next->vm_start are often used. + * We don't use vma_start_write_killable() because page tables should be freed + * even if the task is being killed. * * The vma_end differs from the pg_end when a dup_mmap() failed and the tree has * unrelated data to the mm_struct being torn down. diff --git a/mm/mempolicy.c b/mm/mempolicy.c index fd08771e2057..c38a90487531 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1784,7 +1784,8 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le return -EINVAL; if (end == start) return 0; - mmap_write_lock(mm); + if (mmap_write_lock_killable(mm)) + return -EINTR; prev = vma_prev(&vmi); for_each_vma_range(vmi, vma, end) { /* @@ -1801,13 +1802,19 @@ SYSCALL_DEFINE4(set_mempolicy_home_node, unsigned long, start, unsigned long, le err = -EOPNOTSUPP; break; } + /* + * Lock the VMA early to avoid extra work if fatal signal + * is pending. + */ + err = vma_start_write_killable(vma); + if (err) + break; new = mpol_dup(old); if (IS_ERR(new)) { err = PTR_ERR(new); break; } - vma_start_write(vma); new->home_node = home_node; err = mbind_range(&vmi, vma, &prev, start, end, new); mpol_put(new); diff --git a/mm/mlock.c b/mm/mlock.c index 8c227fefa2df..3d9147f3d404 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -419,8 +419,10 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr, * * Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED; * called for munlock() and munlockall(), to clear VM_LOCKED from @vma. + * + * Return: 0 on success, -EINTR if fatal signal is pending. */ -static void mlock_vma_pages_range(struct vm_area_struct *vma, +static int mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end, vma_flags_t *new_vma_flags) { @@ -442,7 +444,9 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, */ if (vma_flags_test(new_vma_flags, VMA_LOCKED_BIT)) vma_flags_set(new_vma_flags, VMA_IO_BIT); - vma_start_write(vma); + if (vma_start_write_killable(vma)) + return -EINTR; + vma_flags_reset_once(vma, new_vma_flags); lru_add_drain(); @@ -453,6 +457,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma, vma_flags_clear(new_vma_flags, VMA_IO_BIT); vma_flags_reset_once(vma, new_vma_flags); } + return 0; } /* @@ -506,11 +511,13 @@ static int mlock_fixup(struct vma_iterator *vmi, struct vm_area_struct *vma, */ if (vma_flags_test(&new_vma_flags, VMA_LOCKED_BIT) && vma_flags_test(&old_vma_flags, VMA_LOCKED_BIT)) { + ret = vma_start_write_killable(vma); + if (ret) + goto out; /* mm->locked_vm is fine as nr_pages == 0 */ /* No work to do, and mlocking twice would be wrong */ - vma_start_write(vma); vma->flags = new_vma_flags; } else { - mlock_vma_pages_range(vma, start, end, &new_vma_flags); + ret = mlock_vma_pages_range(vma, start, end, &new_vma_flags); } out: *prev = vma; @@ -739,9 +746,18 @@ static int apply_mlockall_flags(int flags) error = mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end, newflags); - /* Ignore errors, but prev needs fixing up. */ - if (error) + if (error) { + /* + * If we failed due to a pending fatal signal, return + * now. If we locked the vma before signal arrived, it + * will be unlocked when we drop mmap_write_lock. + */ + if (fatal_signal_pending(current)) + return -EINTR; + + /* Ignore errors, but prev needs fixing up. */ prev = vma; + } cond_resched(); } out: diff --git a/mm/mprotect.c b/mm/mprotect.c index 110d47a36d4b..ae6ed882b600 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -768,7 +768,10 @@ mprotect_fixup(struct vma_iterator *vmi, struct mmu_gather *tlb, * vm_flags and vm_page_prot are protected by the mmap_lock * held in write mode. */ - vma_start_write(vma); + error = vma_start_write_killable(vma); + if (error) + goto fail; + vma_flags_reset_once(vma, &new_vma_flags); if (vma_wants_manual_pte_write_upgrade(vma)) mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE; diff --git a/mm/mremap.c b/mm/mremap.c index e9c8b1d05832..0860102bddab 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1348,6 +1348,11 @@ static unsigned long move_vma(struct vma_remap_struct *vrm) if (err) return err; + /* We don't want racing faults. */ + err = vma_start_write_killable(vrm->vma); + if (err) + return err; + /* * If accounted, determine the number of bytes the operation will * charge. @@ -1355,9 +1360,6 @@ static unsigned long move_vma(struct vma_remap_struct *vrm) if (!vrm_calc_charge(vrm)) return -ENOMEM; - /* We don't want racing faults. */ - vma_start_write(vrm->vma); - /* Perform copy step. */ err = copy_vma_and_data(vrm, &new_vma); /* diff --git a/mm/mseal.c b/mm/mseal.c index 603df53ad267..3b7737ba7524 100644 --- a/mm/mseal.c +++ b/mm/mseal.c @@ -70,6 +70,7 @@ static int mseal_apply(struct mm_struct *mm, if (!vma_test(vma, VMA_SEALED_BIT)) { vma_flags_t vma_flags = vma->flags; + int err; vma_flags_set(&vma_flags, VMA_SEALED_BIT); @@ -77,7 +78,9 @@ static int mseal_apply(struct mm_struct *mm, curr_end, &vma_flags); if (IS_ERR(vma)) return PTR_ERR(vma); - vma_start_write(vma); + err = vma_start_write_killable(vma); + if (err) + return err; vma_set_flags(vma, VMA_SEALED_BIT); } -- 2.53.0.1018.g2bb0e51243-goog