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From: Derrick McKee <derrick.mckee@gmail.com>
To: Linux Memory Management List <linux-mm@kvack.org>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
	 iamjoonsoo.kim@lge.com,
	Andrew Morton <akpm@linux-foundation.org>
Subject: slab_alloc_node with CONFIG_SLAB_FREELIST_HARDENED
Date: Tue, 11 May 2021 11:52:35 -0400	[thread overview]
Message-ID: <CAJoBWHxLh6oz4UYTaowyY5WKLxho_SS43=xe171mcDe1thfD4A@mail.gmail.com> (raw)

Hi,

I am trying to understand how slab_alloc_node works in mm/slub.c when
CONFIG_SLAB_FREELIST_HARDENED=y. It seems like in ___slab_alloc,
c->freelist gets assigned the result of get_freepointer, which, when
CONFIG_SLAB_FREELIST_HARDENED=y, returns a value XOR'd with a
per-cache random number.  However, that XOR'd value is never seemingly
undone, and slab_alloc_node passes the XOR'd (and thus invalid)
pointer directly to get_freepointer.  Does anyone know where the XOR
reversal is performed?  Thanks.

-- 
Derrick McKee


                 reply	other threads:[~2021-05-11 15:52 UTC|newest]

Thread overview: [no followups] expand[flat|nested]  mbox.gz  Atom feed

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