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From: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
To: linux-hardening@vger.kernel.org
Subject: [RFC] Approaches to deal with a struct with multiple fake flexible arrays members
Date: Wed, 9 Nov 2022 16:45:42 +1300	[thread overview]
Message-ID: <Y2siZmiTD40mTYpJ@mail.google.com> (raw)

Hi KSPP community,

I've been working on replacing 1-element arrays with flex array members
on the drm/amdgpu files. I came across one insteresting case which I
may need to pick your brains to find a solution for it.

The structure below has two fake flexible arrays but I would get an
error if I try make them both FAM. How should/could I deal with the
asRegIndexBuf in this case? In theory, DECLARE_FLEX_ARRAY would "work"
but that doesn't seem to be its intended usage as far I've searched.
(unless I got it wrong, if that's the case, feel free to set me straight)

Any ideas? 

struct _ATOM_INIT_REG_BLOCK {
	USHORT                     usRegIndexTblSize;    /*     0     2 */
	USHORT                     usRegDataBlkSize;     /*     2     2 */
	ATOM_INIT_REG_INDEX_FORMAT asRegIndexBuf[1];     /*     4     3 */
	ATOM_MEMORY_SETTING_DATA_BLOCK asRegDataBuf[1];  /*     7     8 */

	/* size: 15, cachelines: 1, members: 4 */
	/* last cacheline: 15 bytes */
} __attribute__((__packed__));

thanks!

- Paulo A.

             reply	other threads:[~2022-11-09  3:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-09  3:45 Paulo Miguel Almeida [this message]
2022-11-10  0:45 ` [RFC] Approaches to deal with a struct with multiple fake flexible arrays members Gustavo A. R. Silva
2022-11-10  1:31   ` Paulo Miguel Almeida
2022-11-10  3:20     ` Alex Deucher
2022-11-11  5:39       ` Gustavo A. R. Silva
2022-11-11  6:05         ` Paulo Miguel Almeida

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