From: Vlastimil Babka <vbabka@suse.cz>
To: Harry Yoo <harry.yoo@oracle.com>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-mm@kvack.org, Roman Gushchin <roman.gushchin@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>,
Pekka Enberg <penberg@kernel.org>,
Christoph Lameter <cl@linux.com>, Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH] slab: Mark large folios for debugging purposes
Date: Wed, 5 Mar 2025 10:03:06 +0100 [thread overview]
Message-ID: <2f4fd116-1e1d-4800-9351-c625ecd0d2bd@suse.cz> (raw)
In-Reply-To: <Z8agAbWi2z2X_yBp@harry>
On 3/4/25 07:38, Harry Yoo wrote:
> On Mon, Mar 03, 2025 at 05:28:05PM +0000, Matthew Wilcox (Oracle) wrote:
>> If a user calls p = kmalloc(1024); kfree(p); kfree(p); and 'p' was the
>> only object in the slab, we may free the slab after the first call to
>> kfree(). If we do, we clear PGTY_slab and the second call to kfree()
>> will call free_large_kmalloc(). That will leave a trace in the logs
>> ("object pointer: 0x%p"), but otherwise proceed to free the memory,
>> which is likely to corrupt the page allocator's metadata.
>>
>> Allocate a new page type for large kmalloc and mark the memory with it
>> while it's allocated. That lets us detect this double-free and return
>> without harming any data structures.
>>
>> Reported-by: Hannes Reinecke <hare@suse.com>
>> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
>> ---
>
> Looks good to me,
> Reviewed-by: Harry Yoo <harry.yoo@oracle.com>
Added to slab/for-next, thanks!
prev parent reply other threads:[~2025-03-05 19:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-03-03 17:28 Matthew Wilcox (Oracle)
2025-03-04 6:38 ` Harry Yoo
2025-03-05 9:03 ` Vlastimil Babka [this message]
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