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From: Suren Baghdasaryan <surenb@google.com>
To: Laurent Dufour <ldufour@linux.ibm.com>
Cc: akpm@linux-foundation.org, michel@lespinasse.org,
	jglisse@google.com,  mhocko@suse.com, vbabka@suse.cz,
	hannes@cmpxchg.org, mgorman@suse.de,  dave@stgolabs.net,
	willy@infradead.org, liam.howlett@oracle.com,
	 peterz@infradead.org, laurent.dufour@fr.ibm.com,
	paulmck@kernel.org,  luto@kernel.org, songliubraving@fb.com,
	peterx@redhat.com, david@redhat.com,  dhowells@redhat.com,
	hughd@google.com, bigeasy@linutronix.de,
	 kent.overstreet@linux.dev, rientjes@google.com,
	axelrasmussen@google.com,  joelaf@google.com, minchan@google.com,
	kernel-team@android.com,  linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org,
	 linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH RESEND 15/28] mm/mmap: mark adjacent VMAs as locked if they can grow into unmapped area
Date: Fri, 9 Sep 2022 09:25:08 -0700	[thread overview]
Message-ID: <CAJuCfpHoGFv=mRfjsXpFn6Ykwc_SubfL1333Cz-HHYaoiD_73w@mail.gmail.com> (raw)
In-Reply-To: <83a36761-2045-3f46-3088-a751c5263b81@linux.ibm.com>

On Fri, Sep 9, 2022 at 6:43 AM Laurent Dufour <ldufour@linux.ibm.com> wrote:
>
> Le 01/09/2022 à 19:35, Suren Baghdasaryan a écrit :
> > While unmapping VMAs, adjacent VMAs might be able to grow into the area
> > being unmapped. In such cases mark adjacent VMAs as locked to prevent
> > this growth.
> >
> > Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> > ---
> >  mm/mmap.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/mmap.c b/mm/mmap.c
> > index b0d78bdc0de0..b31cc97c2803 100644
> > --- a/mm/mmap.c
> > +++ b/mm/mmap.c
> > @@ -2680,10 +2680,14 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
> >        * VM_GROWSUP VMA. Such VMAs can change their size under
> >        * down_read(mmap_lock) and collide with the VMA we are about to unmap.
> >        */
> > -     if (vma && (vma->vm_flags & VM_GROWSDOWN))
> > +     if (vma && (vma->vm_flags & VM_GROWSDOWN)) {
> > +             vma_mark_locked(vma);
> >               return false;
> > -     if (prev && (prev->vm_flags & VM_GROWSUP))
> > +     }
> > +     if (prev && (prev->vm_flags & VM_GROWSUP)) {
> > +             vma_mark_locked(prev);
> >               return false;
> > +     }
> >       return true;
> >  }
> >
>
> That looks right to be.
>
> But, in addition to that, like the previous patch, all the VMAs to be
> detached from the tree in the loop above, should be marked locked just
> before calling vm_rb_erase().

The following call chain already locks the VMA being isolated:
vma_rb_erase->vma_rb_erase_ignore->__vma_rb_erase->vma_mark_locked

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  reply	other threads:[~2022-09-09 16:26 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-01 17:34 [RFC PATCH RESEND 00/28] per-VMA locks proposal Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 01/28] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 02/28] mm: rcu safe VMA freeing Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 03/28] mm: introduce __find_vma to be used without mmap_lock protection Suren Baghdasaryan
2022-09-01 20:22   ` Kent Overstreet
2022-09-01 23:18     ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 04/28] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2022-09-01 20:24   ` Kent Overstreet
2022-09-01 20:51     ` Liam Howlett
2022-09-01 23:21       ` Suren Baghdasaryan
2022-09-02  6:23     ` Sebastian Andrzej Siewior
2022-09-02 17:46       ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 05/28] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2022-09-06 13:46   ` Laurent Dufour
2022-09-06 17:24     ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 06/28] mm: mark VMA as locked whenever vma->vm_flags are modified Suren Baghdasaryan
2022-09-06 14:26   ` Laurent Dufour
2022-09-06 19:00     ` Suren Baghdasaryan
2022-09-06 20:00       ` Liam Howlett
2022-09-06 20:13         ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 07/28] kernel/fork: mark VMAs as locked before copying pages during fork Suren Baghdasaryan
2022-09-06 14:37   ` Laurent Dufour
2022-09-08 23:57     ` Suren Baghdasaryan
2022-09-09 13:27       ` Laurent Dufour
2022-09-09 16:29         ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 08/28] mm/khugepaged: mark VMA as locked while collapsing a hugepage Suren Baghdasaryan
2022-09-06 14:43   ` Laurent Dufour
2022-09-09  0:15     ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 09/28] mm/mempolicy: mark VMA as locked when changing protection policy Suren Baghdasaryan
2022-09-06 14:47   ` Laurent Dufour
2022-09-09  0:27     ` Suren Baghdasaryan
2022-09-01 17:34 ` [RFC PATCH RESEND 10/28] mm/mmap: mark VMAs as locked in vma_adjust Suren Baghdasaryan
2022-09-06 15:35   ` Laurent Dufour
2022-09-09  0:51     ` Suren Baghdasaryan
2022-09-09 15:52       ` Laurent Dufour
2022-09-01 17:34 ` [RFC PATCH RESEND 11/28] mm/mmap: mark VMAs as locked before merging or splitting them Suren Baghdasaryan
2022-09-06 15:44   ` Laurent Dufour
2022-09-01 17:35 ` [RFC PATCH RESEND 12/28] mm/mremap: mark VMA as locked while remapping it to a new address range Suren Baghdasaryan
2022-09-06 16:09   ` Laurent Dufour
2022-09-01 17:35 ` [RFC PATCH RESEND 13/28] mm: conditionally mark VMA as locked in free_pgtables and unmap_page_range Suren Baghdasaryan
2022-09-09 10:33   ` Laurent Dufour
2022-09-09 16:43     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 14/28] mm: mark VMAs as locked before isolating them Suren Baghdasaryan
2022-09-09 13:35   ` Laurent Dufour
2022-09-09 16:28     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 15/28] mm/mmap: mark adjacent VMAs as locked if they can grow into unmapped area Suren Baghdasaryan
2022-09-09 13:43   ` Laurent Dufour
2022-09-09 16:25     ` Suren Baghdasaryan [this message]
2022-09-01 17:35 ` [RFC PATCH RESEND 16/28] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2022-09-09 13:56   ` Laurent Dufour
2022-09-09 16:19     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 17/28] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2022-09-09 14:20   ` Laurent Dufour
2022-09-09 16:12     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 18/28] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2022-09-09 14:26   ` Laurent Dufour
2022-09-01 17:35 ` [RFC PATCH RESEND 19/28] mm: disallow do_swap_page to handle page faults under VMA lock Suren Baghdasaryan
2022-09-06 19:39   ` Peter Xu
2022-09-06 20:08     ` Suren Baghdasaryan
2022-09-06 20:22       ` Peter Xu
2022-09-07  0:58         ` Suren Baghdasaryan
2022-09-09 14:26   ` Laurent Dufour
2022-09-01 17:35 ` [RFC PATCH RESEND 20/28] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2022-09-09 14:28   ` Laurent Dufour
2022-09-09 16:11     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 21/28] mm: introduce find_and_lock_anon_vma to be used from arch-specific code Suren Baghdasaryan
2022-09-09 14:38   ` Laurent Dufour
2022-09-09 16:10     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 22/28] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 23/28] x86/mm: define ARCH_SUPPORTS_PER_VMA_LOCK Suren Baghdasaryan
2022-09-01 20:20   ` Kent Overstreet
2022-09-01 23:17     ` Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 24/28] arm64/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 25/28] arm64/mm: define ARCH_SUPPORTS_PER_VMA_LOCK Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 26/28] powerc/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 27/28] powerpc/mm: define ARCH_SUPPORTS_PER_VMA_LOCK Suren Baghdasaryan
2022-09-01 17:35 ` [RFC PATCH RESEND 28/28] kernel/fork: throttle call_rcu() calls in vm_area_free Suren Baghdasaryan
2022-09-09 15:19   ` Laurent Dufour
2022-09-09 16:02     ` Suren Baghdasaryan
2022-09-09 16:14       ` Laurent Dufour
2022-09-01 20:58 ` [RFC PATCH RESEND 00/28] per-VMA locks proposal Kent Overstreet
2022-09-01 23:26   ` Suren Baghdasaryan
2022-09-11  9:35     ` Vlastimil Babka
2022-09-28  2:28       ` Suren Baghdasaryan
2022-09-29 11:18         ` Vlastimil Babka
2022-09-02  7:42 ` Peter Zijlstra
2022-09-02 14:45   ` Suren Baghdasaryan
2022-09-05 12:32 ` Michal Hocko
2022-09-05 18:32   ` Suren Baghdasaryan
2022-09-05 20:35     ` Kent Overstreet
2022-09-06 15:46       ` Suren Baghdasaryan

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