From: Pedro Falcato <pfalcato@suse.de>
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
maple-tree@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
David Hildenbrand <david@redhat.com>,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jann Horn <jannh@google.com>,
Charan Teja Kalla <quic_charante@quicinc.com>,
shikemeng@huaweicloud.com, kasong@tencent.com, nphamcs@gmail.com,
bhe@redhat.com, baohua@kernel.org, chrisl@kernel.org,
Matthew Wilcox <willy@infradead.org>
Subject: Re: [PATCH v1 6/9] mm: Change dup_mmap() recovery
Date: Wed, 10 Sep 2025 14:23:48 +0100 [thread overview]
Message-ID: <fkfi4zldsecyio6xnd6blou27me4nno3v3tnsaxz6xlt63yy2z@nxl7izptm6yx> (raw)
In-Reply-To: <20250909190945.1030905-7-Liam.Howlett@oracle.com>
On Tue, Sep 09, 2025 at 03:09:42PM -0400, Liam R. Howlett wrote:
> When the dup_mmap() fails during the vma duplication or setup, don't
> write the XA_ZERO entry in the vma tree. Instead, destroy the tree and
> free the new resources, leaving an empty vma tree.
>
> Using XA_ZERO introduced races where the vma could be found between
> dup_mmap() dropping all locks and exit_mmap() taking the locks. The
> race can occur because the mm can be reached through the other trees
> via successfully copied vmas and other methods such as the swapoff code.
>
> XA_ZERO was marking the location to stop vma removal and pagetable
> freeing. The newly created arguments to the unmap_vmas() and
> free_pgtables() serve this function.
>
> Replacing the XA_ZERO entry use with the new argument list also means
> the checks for xa_is_zero() are no longer necessary so these are also
> removed.
>
> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
--
Pedro
next prev parent reply other threads:[~2025-09-10 13:24 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-09 19:09 [PATCH v1 0/9] Remove XA_ZERO from error recovery of dup_mmap() Liam R. Howlett
2025-09-09 19:09 ` [PATCH v1 1/9] mm/mmap: Move exit_mmap() trace point Liam R. Howlett
2025-09-09 20:07 ` Suren Baghdasaryan
2025-09-10 12:51 ` Pedro Falcato
2025-09-11 9:19 ` David Hildenbrand
2025-09-09 19:09 ` [PATCH v1 2/9] mm/mmap: Abstract vma clean up from exit_mmap() Liam R. Howlett
2025-09-09 20:09 ` Suren Baghdasaryan
2025-09-10 12:54 ` Pedro Falcato
2025-09-11 9:21 ` David Hildenbrand
2025-09-09 19:09 ` [PATCH v1 3/9] mm/vma: Add limits to unmap_region() for vmas Liam R. Howlett
2025-09-09 20:09 ` Suren Baghdasaryan
2025-09-10 12:56 ` Pedro Falcato
2025-09-11 8:56 ` Lorenzo Stoakes
2025-09-11 9:22 ` David Hildenbrand
2025-09-09 19:09 ` [PATCH v1 4/9] mm/memory: Add tree limit to free_pgtables() Liam R. Howlett
2025-09-09 21:05 ` Suren Baghdasaryan
2025-09-10 13:08 ` Pedro Falcato
2025-09-11 9:08 ` Lorenzo Stoakes
2025-09-11 9:24 ` David Hildenbrand
2025-09-09 19:09 ` [PATCH v1 5/9] mm/vma: Add page table limit to unmap_region() Liam R. Howlett
2025-09-09 21:29 ` Suren Baghdasaryan
2025-09-10 13:08 ` Pedro Falcato
2025-09-09 19:09 ` [PATCH v1 6/9] mm: Change dup_mmap() recovery Liam R. Howlett
2025-09-09 22:03 ` Suren Baghdasaryan
2025-09-10 13:23 ` Pedro Falcato [this message]
2025-09-11 9:13 ` Lorenzo Stoakes
2025-09-11 9:31 ` David Hildenbrand
2025-09-09 19:09 ` [PATCH v1 7/9] mm: Introduce unmap_desc struct to reduce function arguments Liam R. Howlett
2025-09-09 21:44 ` Suren Baghdasaryan
2025-09-11 9:22 ` Lorenzo Stoakes
2025-09-11 16:51 ` Suren Baghdasaryan
2025-09-11 16:56 ` Liam R. Howlett
2025-09-11 17:03 ` Suren Baghdasaryan
2025-09-10 13:10 ` Pedro Falcato
2025-09-11 9:20 ` Lorenzo Stoakes
2025-09-09 19:09 ` [PATCH v1 8/9] mm/vma: Use unmap_desc in vms_clear_ptes() and exit_mmap() Liam R. Howlett
2025-09-09 22:16 ` Suren Baghdasaryan
2025-09-11 16:59 ` Liam R. Howlett
2025-09-11 9:53 ` Lorenzo Stoakes
2025-09-12 5:08 ` kernel test robot
2025-09-09 19:09 ` [PATCH v1 9/9] mm: Use unmap_desc struct for freeing page tables Liam R. Howlett
2025-09-09 22:27 ` Suren Baghdasaryan
2025-09-11 10:06 ` Lorenzo Stoakes
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