From nobody Mon Feb 9 23:44:40 2026 Received: from mail-pj1-f74.google.com (mail-pj1-f74.google.com [209.85.216.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 59F18146D45 for ; Thu, 26 Dec 2024 17:07:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735232842; cv=none; b=orBjfNxnl4bsgmr84Ktia7gjpw4li8hH1MY3/g1QLK96zU7Y8i+SLwfPB7cuNqOwLRws/JCSZQ0xfhRN/RLaxilFzefaWg7/y9Jtl0tpOmy4W5+3P/nD18GKU2vl8SRGxj7SQ22QvJAWDrxn4QRUSzn7eVnp7QPYTbOO6s7HluQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735232842; c=relaxed/simple; bh=Vjvp6aRKQ9utdAT+qEZMT61k/JXlv8Qbyaf2UHbSZjs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=k3Kfbq37pvd22yFfiO35lrEDY/Ln66pBsiuN7C9VHIS6rpZRRWK8W5nv7jN/cxVYjIPqRsDcO5rd1xhPonAIN0OVAgLNBl47Vt7pKpJ6/CN+8EIm4mKJCvsgg4lgl6Q1G2Tdyi493HogNu4aASxmv3Z21XjCfV70xf1LAlQNDvQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--surenb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=W5r07BBe; arc=none smtp.client-ip=209.85.216.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--surenb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="W5r07BBe" Received: by mail-pj1-f74.google.com with SMTP id 98e67ed59e1d1-2efa0eb9cfeso7839851a91.0 for ; Thu, 26 Dec 2024 09:07:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1735232840; x=1735837640; darn=vger.kernel.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=cAz4Nb0K6HeFkqWg5wvl8l9ILYUUia2eSNvAxmroFu8=; b=W5r07BBe5waXfXMd0I0iTkZuaEhw8eD8ugjyxYqEB3QoZ5FiPiw/ydR5SBRrH6C3eq hUy5+2LWK4BGO45aKnLDlbwYj5Ets8xR135g07MKmqkmct2mk4///TBW78Vx6/O1kXLO lTKWJuqaQLr0z09/X1i8CkFiIP4nftqWGC0Cvs9Ygw2k6YHWYZARpT/XRp4+tXV92jQK W4wASscuDGHVXWrc++2AQfoALNY45kVaBV31dblxFihe6+ZzG4JOOwrPcBrDEdZc3fbg Jzh8CLliGdn8As3xHy79LK3Rw3SRcagq9RfiwEvcynF5OO2smipmZtbgGvqH3+pmOSAc qcag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1735232840; x=1735837640; 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=cAz4Nb0K6HeFkqWg5wvl8l9ILYUUia2eSNvAxmroFu8=; b=YS8I7NY38N+jxwcrQ29s0cvkmU7kZVLzNhDrCJD0J3BF/wEmdmo+F1MtRKZUWTvqcM 1s5GOTC3FikGnvn12HVvmHAozoP4JREH25cKexqC7VGjJ4YYrFWRerAZLQGvJY3bFEBi oP+sv8F2kw/hOINUl1ekUm+hZ3oJCJxJPHSojQRprmB9yIC9qSdfEUcddMwDdKJq9qt0 zJhOe1/UmPmHGYjIQ4ORLYgpYY4SNjuLCGuE76fkOyOvBBhWa2Hziv+xQ8IvGIHmqDhB rz+hx3Pf1OG4q7AxyOTga5ddTT7MQ1Vmu7H7NOBWctxEMLSHirBosEsZjDG2wMq2JbOr 92xw== X-Forwarded-Encrypted: i=1; AJvYcCUFeUNeLtmynuQECmV0JjMH080hhLztp1ZCYamtR7M4UnnuZAAYDaK5JAoCk9vbWkH+CAliTd+HThtTij8=@vger.kernel.org X-Gm-Message-State: AOJu0Ywtmn6o1/Otxe/6l69Lrp1/s45Ey/v4/BnpIFfEnSBc/8G74lD4 ylUO0CzUupZnD3CvKwiQZSURGqUSmEoYeBd4CvSkEQnGUicXBjwrET2LNCcQFRJqAx8uUkCcTld gJw== X-Google-Smtp-Source: AGHT+IHG75OaLxopGAtkxZlDDT2v+C2m79NALqlAe4xW7nBDhmw9thNrZbKpynlUfVT/naik0hkFrK8zsZY= X-Received: from pjbtb12.prod.google.com ([2002:a17:90b:53cc:b0:2ef:7483:e770]) (user=surenb job=prod-delivery.src-stubby-dispatcher) by 2002:a17:90b:5251:b0:2f2:a90e:74ef with SMTP id 98e67ed59e1d1-2f44353f0b2mr41720800a91.1.1735232839810; Thu, 26 Dec 2024 09:07:19 -0800 (PST) Date: Thu, 26 Dec 2024 09:06:55 -0800 In-Reply-To: <20241226170710.1159679-1-surenb@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20241226170710.1159679-1-surenb@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20241226170710.1159679-4-surenb@google.com> Subject: [PATCH v7 03/17] mm: mark vma as detached until it's added into vma tree From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: peterz@infradead.org, willy@infradead.org, liam.howlett@oracle.com, lorenzo.stoakes@oracle.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mjguzik@gmail.com, oliver.sang@intel.com, mgorman@techsingularity.net, david@redhat.com, peterx@redhat.com, oleg@redhat.com, dave@stgolabs.net, paulmck@kernel.org, brauner@kernel.org, dhowells@redhat.com, hdanton@sina.com, hughd@google.com, lokeshgidra@google.com, minchan@google.com, jannh@google.com, shakeel.butt@linux.dev, souravpanda@google.com, pasha.tatashin@soleen.com, klarasmodin@gmail.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Current implementation does not set detached flag when a VMA is first allocated. This does not represent the real state of the VMA, which is detached until it is added into mm's VMA tree. Fix this by marking new VMAs as detached and resetting detached flag only after VMA is added into a tree. Introduce vma_mark_attached() to make the API more readable and to simplify possible future cleanup when vma->vm_mm might be used to indicate detached vma and vma_mark_attached() will need an additional mm parameter. Signed-off-by: Suren Baghdasaryan Reviewed-by: Shakeel Butt Reviewed-by: Lorenzo Stoakes Reviewed-by: Vlastimil Babka Reviewed-by: Liam R. Howlett --- include/linux/mm.h | 27 ++++++++++++++++++++------- kernel/fork.c | 4 ++++ mm/memory.c | 2 +- mm/vma.c | 6 +++--- mm/vma.h | 2 ++ tools/testing/vma/vma_internal.h | 17 ++++++++++++----- 6 files changed, 42 insertions(+), 16 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index f3f92ba8f5fe..081178b0eec4 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -821,12 +821,21 @@ static inline void vma_assert_locked(struct vm_area_s= truct *vma) vma_assert_write_locked(vma); } =20 -static inline void vma_mark_detached(struct vm_area_struct *vma, bool deta= ched) +static inline void vma_mark_attached(struct vm_area_struct *vma) +{ + vma->detached =3D false; +} + +static inline void vma_mark_detached(struct vm_area_struct *vma) { /* When detaching vma should be write-locked */ - if (detached) - vma_assert_write_locked(vma); - vma->detached =3D detached; + vma_assert_write_locked(vma); + vma->detached =3D true; +} + +static inline bool is_vma_detached(struct vm_area_struct *vma) +{ + return vma->detached; } =20 static inline void release_fault_lock(struct vm_fault *vmf) @@ -857,8 +866,8 @@ static inline void vma_end_read(struct vm_area_struct *= vma) {} static inline void vma_start_write(struct vm_area_struct *vma) {} static inline void vma_assert_write_locked(struct vm_area_struct *vma) { mmap_assert_write_locked(vma->vm_mm); } -static inline void vma_mark_detached(struct vm_area_struct *vma, - bool detached) {} +static inline void vma_mark_attached(struct vm_area_struct *vma) {} +static inline void vma_mark_detached(struct vm_area_struct *vma) {} =20 static inline struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *= mm, unsigned long address) @@ -891,7 +900,10 @@ static inline void vma_init(struct vm_area_struct *vma= , struct mm_struct *mm) vma->vm_mm =3D mm; vma->vm_ops =3D &vma_dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); +#ifdef CONFIG_PER_VMA_LOCK + /* vma is not locked, can't use vma_mark_detached() */ + vma->detached =3D true; +#endif vma_numab_state_init(vma); vma_lock_init(vma); } @@ -1086,6 +1098,7 @@ static inline int vma_iter_bulk_store(struct vma_iter= ator *vmi, if (unlikely(mas_is_err(&vmi->mas))) return -ENOMEM; =20 + vma_mark_attached(vma); return 0; } =20 diff --git a/kernel/fork.c b/kernel/fork.c index 40a8e615499f..f2f9e7b427ad 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -465,6 +465,10 @@ struct vm_area_struct *vm_area_dup(struct vm_area_stru= ct *orig) data_race(memcpy(new, orig, sizeof(*new))); vma_lock_init(new); INIT_LIST_HEAD(&new->anon_vma_chain); +#ifdef CONFIG_PER_VMA_LOCK + /* vma is not locked, can't use vma_mark_detached() */ + new->detached =3D true; +#endif vma_numab_state_init(new); dup_anon_vma_name(orig, new); =20 diff --git a/mm/memory.c b/mm/memory.c index 2a20e3810534..d0dee2282325 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6349,7 +6349,7 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_s= truct *mm, goto inval; =20 /* Check if the VMA got isolated after we found it */ - if (vma->detached) { + if (is_vma_detached(vma)) { vma_end_read(vma); count_vm_vma_lock_event(VMA_LOCK_MISS); /* The area was replaced with another one */ diff --git a/mm/vma.c b/mm/vma.c index 0caaeea899a9..476146c25283 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -327,7 +327,7 @@ static void vma_complete(struct vma_prepare *vp, struct= vma_iterator *vmi, =20 if (vp->remove) { again: - vma_mark_detached(vp->remove, true); + vma_mark_detached(vp->remove); if (vp->file) { uprobe_munmap(vp->remove, vp->remove->vm_start, vp->remove->vm_end); @@ -1220,7 +1220,7 @@ static void reattach_vmas(struct ma_state *mas_detach) =20 mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - vma_mark_detached(vma, false); + vma_mark_attached(vma); =20 __mt_destroy(mas_detach->tree); } @@ -1295,7 +1295,7 @@ static int vms_gather_munmap_vmas(struct vma_munmap_s= truct *vms, if (error) goto munmap_gather_failed; =20 - vma_mark_detached(next, true); + vma_mark_detached(next); nrpages =3D vma_pages(next); =20 vms->nr_pages +=3D nrpages; diff --git a/mm/vma.h b/mm/vma.h index 61ed044b6145..24636a2b0acf 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -157,6 +157,7 @@ static inline int vma_iter_store_gfp(struct vma_iterato= r *vmi, if (unlikely(mas_is_err(&vmi->mas))) return -ENOMEM; =20 + vma_mark_attached(vma); return 0; } =20 @@ -389,6 +390,7 @@ static inline void vma_iter_store(struct vma_iterator *= vmi, =20 __mas_set_range(&vmi->mas, vma->vm_start, vma->vm_end - 1); mas_store_prealloc(&vmi->mas, vma); + vma_mark_attached(vma); } =20 static inline unsigned long vma_iter_addr(struct vma_iterator *vmi) diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_inter= nal.h index d19ce6fcab83..2a624f9304da 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -465,13 +465,17 @@ static inline void vma_lock_init(struct vm_area_struc= t *vma) vma->vm_lock_seq =3D UINT_MAX; } =20 +static inline void vma_mark_attached(struct vm_area_struct *vma) +{ + vma->detached =3D false; +} + static inline void vma_assert_write_locked(struct vm_area_struct *); -static inline void vma_mark_detached(struct vm_area_struct *vma, bool deta= ched) +static inline void vma_mark_detached(struct vm_area_struct *vma) { /* When detaching vma should be write-locked */ - if (detached) - vma_assert_write_locked(vma); - vma->detached =3D detached; + vma_assert_write_locked(vma); + vma->detached =3D true; } =20 extern const struct vm_operations_struct vma_dummy_vm_ops; @@ -484,7 +488,8 @@ static inline void vma_init(struct vm_area_struct *vma,= struct mm_struct *mm) vma->vm_mm =3D mm; vma->vm_ops =3D &vma_dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); + /* vma is not locked, can't use vma_mark_detached() */ + vma->detached =3D true; vma_lock_init(vma); } =20 @@ -510,6 +515,8 @@ static inline struct vm_area_struct *vm_area_dup(struct= vm_area_struct *orig) memcpy(new, orig, sizeof(*new)); vma_lock_init(new); INIT_LIST_HEAD(&new->anon_vma_chain); + /* vma is not locked, can't use vma_mark_detached() */ + new->detached =3D true; =20 return new; } --=20 2.47.1.613.gc27f4b7a9f-goog