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From: Matthew Wilcox <willy@infradead.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	netdev@vger.kernel.org, linux-mm@kvack.org,
	Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCH] mm: Decline to manipulate the refcount on a slab page
Date: Mon, 10 Mar 2025 14:50:19 +0000	[thread overview]
Message-ID: <Z878K7JQ93LqBdCB@casper.infradead.org> (raw)
In-Reply-To: <598912d1-0482-434c-b7bb-75e6fdc2e38e@suse.cz>

On Mon, Mar 10, 2025 at 03:37:51PM +0100, Vlastimil Babka wrote:
> Note it's a 6.14 hotfix for kernel oopses due to page refcount overflow.

Not actually overflow ... without VM_DEBUG enabled, networking increases
the refcount from 0 to 1, then decrements it from 1 to 0, causing the
slab to be freed.  So it's a UAF bug induced by a messed-up refcount.


  reply	other threads:[~2025-03-10 14:50 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-10 14:35 Matthew Wilcox (Oracle)
2025-03-10 14:37 ` Vlastimil Babka
2025-03-10 14:50   ` Matthew Wilcox [this message]
2025-03-11 10:15 ` Jakub Kicinski
2025-03-11 15:46   ` Hannes Reinecke
2025-03-11 16:59     ` Matthew Wilcox
2025-03-12  5:48       ` Christoph Hellwig
2025-03-13  7:22         ` Hannes Reinecke
2025-03-13  7:36           ` Christoph Hellwig
2025-03-13  8:34             ` Hannes Reinecke
2025-03-13  8:44               ` Christoph Hellwig
2025-03-13  8:52                 ` Hannes Reinecke
2025-03-13  9:15                   ` Christoph Hellwig
2025-03-12  5:47   ` Christoph Hellwig
     [not found] <20250310142750.1209192-1-willy@infradead.org>
     [not found] ` <77fa8d7e-4752-4979-affe-aa45c8d7795a@suse.de>
     [not found]   ` <Z88vUFweLyk5s8UD@casper.infradead.org>
2025-03-11  7:05     ` Hannes Reinecke

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