From: Linus Torvalds <torvalds@linux-foundation.org>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mark Brown <broonie@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Peter Xu <peterx@redhat.com>,
linux-arm-kernel@lists.infradead.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Aishwarya TCV <Aishwarya.TCV@arm.com>
Subject: Re: [PATCH hotfix 6.12 v2 4/8] mm: resolve faulty mmap_region() error path behaviour
Date: Mon, 28 Oct 2024 09:05:44 -1000 [thread overview]
Message-ID: <CAHk-=whD9MrPwPMBgVG16T_u+my8xYtZg2tUGz932HeodVX7Bg@mail.gmail.com> (raw)
In-Reply-To: <c24a174d-c8f3-4267-87ae-cf77fa587e82@lucifer.local>
On Mon, 28 Oct 2024 at 08:57, Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
>
> So likely hook on your mapping changes flags to set VM_MTE | VM_MTE_ALLOWED and
> expects this to be checked after (ugh).
Gaah. Yes. mm/shmem.c: shmem_mmap() does
/* arm64 - allow memory tagging on RAM-based files */
vm_flags_set(vma, VM_MTE_ALLOWED);
and while I found the equivalent hack for the VM_SPARC_ADI case, I
hadn't noticed that MTE thing.
How very annoying.
So the arch_validate_flags() case does need to be done after the ->mmap() call.
How about just finalizing everything, and then doing a regular
munmap() afterwards and returning an error (all still holding the mmap
semaphore, of course).
That still avoids the whole "partially completed mmap" case.
Linus
next prev parent reply other threads:[~2024-10-28 19:06 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-23 20:38 [PATCH v2 0/8] fix error handling in mmap_region() and refactor Lorenzo Stoakes
2024-10-23 20:38 ` [PATCH hotfix 6.12 v2 1/8] mm: avoid unsafe VMA hook invocation when error arises on mmap hook Lorenzo Stoakes
2024-10-23 20:38 ` [PATCH hotfix 6.12 v2 2/8] mm: unconditionally close VMAs on error Lorenzo Stoakes
2024-10-23 20:38 ` [PATCH hotfix 6.12 v2 3/8] mm: refactor map_deny_write_exec() Lorenzo Stoakes
2024-10-23 20:38 ` [PATCH hotfix 6.12 v2 4/8] mm: resolve faulty mmap_region() error path behaviour Lorenzo Stoakes
2024-10-28 18:29 ` Mark Brown
2024-10-28 18:57 ` Lorenzo Stoakes
2024-10-28 19:05 ` Linus Torvalds [this message]
2024-10-28 19:14 ` Lorenzo Stoakes
2024-10-28 19:50 ` Liam R. Howlett
2024-10-28 20:00 ` Liam R. Howlett
2024-10-28 20:17 ` Lorenzo Stoakes
2024-10-28 20:22 ` Linus Torvalds
2024-10-28 20:43 ` Lorenzo Stoakes
2024-10-28 21:04 ` Liam R. Howlett
2024-10-28 21:05 ` Mark Brown
2024-10-28 21:28 ` Lorenzo Stoakes
2024-10-28 21:00 ` Vlastimil Babka
2024-10-28 21:19 ` Linus Torvalds
2024-10-28 21:28 ` Vlastimil Babka
2024-10-28 22:14 ` Lorenzo Stoakes
2024-10-29 7:50 ` Vlastimil Babka
2024-10-29 10:23 ` Lorenzo Stoakes
2024-10-29 12:33 ` Mark Brown
2024-10-29 12:41 ` Lorenzo Stoakes
2024-10-29 15:04 ` Catalin Marinas
2024-10-29 15:16 ` Lorenzo Stoakes
2024-10-29 16:22 ` Catalin Marinas
2024-10-29 16:36 ` Lorenzo Stoakes
2024-10-29 17:02 ` Catalin Marinas
2024-10-29 17:28 ` Lorenzo Stoakes
2024-10-29 17:32 ` Catalin Marinas
2024-10-28 20:51 ` Mark Brown
2024-10-23 20:38 ` [PATCH v2 5/8] tools: testing: add additional vma_internal.h stubs Lorenzo Stoakes
2024-10-23 20:38 ` [PATCH v2 6/8] mm: isolate mmap internal logic to mm/vma.c Lorenzo Stoakes
2024-10-24 17:23 ` Vlastimil Babka
2024-10-23 20:38 ` [PATCH v2 7/8] mm: refactor __mmap_region() Lorenzo Stoakes
2024-10-25 8:35 ` Vlastimil Babka
2024-10-25 10:19 ` Lorenzo Stoakes
2024-10-25 10:23 ` Vlastimil Babka
2024-10-23 20:38 ` [PATCH v2 8/8] mm: defer second attempt at merge on mmap() Lorenzo Stoakes
2024-10-25 9:43 ` Vlastimil Babka
2024-10-25 10:20 ` Lorenzo Stoakes
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