From: Jann Horn <jannh@google.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Suren Baghdasaryan <surenb@google.com>,
Pedro Falcato <pfalcato@suse.de>, Linux-MM <linux-mm@kvack.org>,
kernel list <linux-kernel@vger.kernel.org>
Subject: Re: [BUG] hard-to-hit mm_struct UAF due to insufficiently careful vma_refcount_put() wrt SLAB_TYPESAFE_BY_RCU
Date: Wed, 23 Jul 2025 22:00:40 +0200 [thread overview]
Message-ID: <CAG48ez0782x2dqa5LrK2cf9M0_Q=Gvo5tXsUFQDtyK00LpcvyQ@mail.gmail.com> (raw)
In-Reply-To: <CAG48ez0KE9bfFJ+yAMPUAj=_hcNRfes3=nfQd7Rv95TSnHtUCg@mail.gmail.com>
On Wed, Jul 23, 2025 at 9:52 PM Jann Horn <jannh@google.com> wrote:
> I'm not sure if I'm understanding you correctly; but yes,
> __vma_enter_locked() waits for all the waiters to drop their
> "refcounts". (It's not really a refcount, you can also think of it as
> a sleepable read-write lock where the low bits are the number of
> readers.)
Sorry, that's not entirely true, since an attached VMA has a refcount
elevated by one. It's kind of a refcount, and kind of forms part of a
sleepable read-write lock, it's complicated.
next prev parent reply other threads:[~2025-07-23 20:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-23 16:26 Jann Horn
2025-07-23 17:32 ` Vlastimil Babka
2025-07-23 17:49 ` Jann Horn
2025-07-23 17:55 ` Suren Baghdasaryan
2025-07-23 19:01 ` Lorenzo Stoakes
2025-07-24 0:13 ` Suren Baghdasaryan
2025-07-24 4:40 ` Lorenzo Stoakes
2025-07-23 18:10 ` Vlastimil Babka
2025-07-23 18:19 ` Jann Horn
2025-07-23 18:39 ` Lorenzo Stoakes
2025-07-23 19:52 ` Jann Horn
2025-07-23 20:00 ` Jann Horn [this message]
2025-07-24 5:24 ` Lorenzo Stoakes
2025-07-24 5:23 ` Lorenzo Stoakes
2025-07-23 20:27 ` Suren Baghdasaryan
2025-07-24 2:30 ` Suren Baghdasaryan
2025-07-24 8:38 ` Vlastimil Babka
2025-07-24 10:53 ` Lorenzo Stoakes
2025-07-24 14:29 ` Suren Baghdasaryan
2025-07-24 14:45 ` Vlastimil Babka
2025-07-24 14:52 ` Suren Baghdasaryan
2025-07-24 14:45 ` Jann Horn
2025-07-24 16:36 ` Suren Baghdasaryan
2025-07-28 17:14 ` Suren Baghdasaryan
2025-07-23 18:14 ` Lorenzo Stoakes
2025-07-23 18:30 ` Jann Horn
2025-07-23 18:45 ` Lorenzo Stoakes
2025-07-23 19:43 ` Jann Horn
2025-07-24 5:13 ` Lorenzo Stoakes
2025-07-24 14:50 ` Jann Horn
2025-07-24 14:56 ` Lorenzo Stoakes
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