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From: David Hildenbrand <david@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: syzbot <syzbot+c0673e1f1f054fac28c2@syzkaller.appspotmail.com>,
	akpm@linux-foundation.org, hdanton@sina.com,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	syzkaller-bugs@googlegroups.com,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Subject: Re: [syzbot] [mm?] WARNING in __folio_rmap_sanity_checks (2)
Date: Fri, 10 Jan 2025 17:31:37 +0100	[thread overview]
Message-ID: <51de00af-9860-4617-80d4-8c9818bcce3d@redhat.com> (raw)
In-Reply-To: <Z4FKV8cPJJZjDhyz@casper.infradead.org>

On 10.01.25 17:27, Matthew Wilcox wrote:
> On Fri, Jan 10, 2025 at 05:19:54PM +0100, David Hildenbrand wrote:
>> On 10.01.25 17:14, Matthew Wilcox wrote:
>>> On Fri, Jan 10, 2025 at 04:48:03PM +0100, David Hildenbrand wrote:
>>>> If I would have to guess, I would assume that we have a refcount issue such
>>>> that we succeed in splitting a folio while concurrently mapping it.
>>>
>>> That would seem hard to accomplish, because both hold the folio lock,
>>> so it wouldn't be just a refcount bug but also a locking bug.  Not sure
>>> what this is though.
>>
>> Yeah, but we also have
>>
>> https://lkml.kernel.org/r/6774bf44.050a0220.25abdd.098a.GAE@google.com
> 
> That one is a UAF on the vma, so it's either a different issue, or the
> problem is with the VMA refcount/lookup/..., not the folio refcount.
> cc'ing the relevant maintainers.

Agreed, it's all a bit confusing.

-- 
Cheers,

David / dhildenb



  reply	other threads:[~2025-01-10 16:31 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-11  1:54 syzbot
2024-12-11 10:06 ` David Hildenbrand
2024-12-28  4:56 ` syzbot
2024-12-31  8:41   ` Hillf Danton
2024-12-31  9:09     ` syzbot
2025-01-10 16:35     ` David Hildenbrand
2025-01-11  1:00       ` Hillf Danton
2025-01-11 10:03         ` David Hildenbrand
2024-12-28 12:25 ` syzbot
2025-01-10 15:48   ` David Hildenbrand
2025-01-10 16:14     ` Matthew Wilcox
2025-01-10 16:19       ` David Hildenbrand
2025-01-10 16:27         ` Matthew Wilcox
2025-01-10 16:31           ` David Hildenbrand [this message]
2025-01-10 19:55             ` Liam R. Howlett
2025-01-10 21:24               ` Suren Baghdasaryan
2025-01-11  4:29                 ` Liam R. Howlett
2025-01-10 21:03   ` Liam R. Howlett
2025-01-11  6:15     ` syzbot
2025-01-11  9:25     ` David Hildenbrand
2025-01-11  9:54       ` syzbot
2025-01-13 15:39         ` David Hildenbrand
2025-01-13 15:45           ` Liam R. Howlett
2025-01-13 15:50             ` David Hildenbrand

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