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From: Andrew Morton <akpm@linux-foundation.org>
To: Jann Horn <jannh@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>,
	torvalds@linux-foundation.org, willy@infradead.org,
	liam.howlett@oracle.com, david@redhat.com, peterx@redhat.com,
	ldufour@linux.ibm.com, vbabka@suse.cz, michel@lespinasse.org,
	jglisse@google.com, mhocko@suse.com, hannes@cmpxchg.org,
	dave@stgolabs.net, hughd@google.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	kernel-team@android.com
Subject: Re: [PATCH v4 5/6] mm: always lock new vma before inserting into vma tree
Date: Mon, 14 Aug 2023 12:15:21 -0700	[thread overview]
Message-ID: <20230814121521.83c2dda21765757d272538b2@linux-foundation.org> (raw)
In-Reply-To: <CAG48ez0XCXoXbSR6dyX7GUQYJKRFKQsHuye5q-PLU3-gR5of5A@mail.gmail.com>

On Mon, 14 Aug 2023 16:54:01 +0200 Jann Horn <jannh@google.com> wrote:

> > @@ -403,6 +403,8 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
> >
> >   vma_iter_store(&vmi, vma);
> >
> > + vma_start_write(vma);
> > +
> >   if (vma->vm_file) {
> >  mapping = vma->vm_file->f_mapping;
> >  i_mmap_lock_write(mapping);
> 
> The "vma_start_write()" has to be ordered before the
> "vma_iter_store(&vmi, vma)".

Thanks.  This?


--- a/mm/mmap.c~mm-always-lock-new-vma-before-inserting-into-vma-tree-fix
+++ a/mm/mmap.c
@@ -401,10 +401,10 @@ static int vma_link(struct mm_struct *mm
 	if (vma_iter_prealloc(&vmi, vma))
 		return -ENOMEM;
 
-	vma_iter_store(&vmi, vma);
-
 	vma_start_write(vma);
 
+	vma_iter_store(&vmi, vma);
+
 	if (vma->vm_file) {
 		mapping = vma->vm_file->f_mapping;
 		i_mmap_lock_write(mapping);
_



  reply	other threads:[~2023-08-14 19:15 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-04 15:27 [PATCH v4 0/6] make vma locking more obvious Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 1/6] mm: enable page walking API to lock vmas during the walk Suren Baghdasaryan
2023-08-04 19:14   ` Andrew Morton
2023-08-04 19:41     ` Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 2/6] mm: for !CONFIG_PER_VMA_LOCK equate write lock assertion for vma and mmap Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 3/6] mm: replace mmap with vma write lock assertions when operating on a vma Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 4/6] mm: lock vma explicitly before doing vm_flags_reset and vm_flags_reset_once Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 5/6] mm: always lock new vma before inserting into vma tree Suren Baghdasaryan
2023-08-14 14:54   ` Jann Horn
2023-08-14 19:15     ` Andrew Morton [this message]
2023-08-14 19:19       ` Liam R. Howlett
2023-08-14 20:02       ` Jann Horn
2023-08-14 20:06         ` Suren Baghdasaryan
2023-08-04 15:27 ` [PATCH v4 6/6] mm: move vma locking out of vma_prepare and dup_anon_vma Suren Baghdasaryan

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