linux-kernel - -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection for kernel data)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <1290410581.2405.24.camel@minggr.sh.intel.com>
Date:	Mon, 22 Nov 2010 15:23:01 +0800
From:	Lin Ming <ming.m.lin@...el.com>
To:	Matthieu Castet <castet.matthieu@...e.fr>,
	Siarhei Liakh <sliakh.lkml@...il.com>,
	Xuxian Jiang <jiang@...ncsu.edu>, Ingo Molnar <mingo@...e.hu>
Cc:	Arjan van de Ven <arjan@...radead.org>,
	Andi Kleen <andi@...stfloor.org>,
	lkml <linux-kernel@...r.kernel.org>
Subject: -tip tree resume fail, bisect to 5bd5a45(x86: Add NX protection
 for kernel data)

Hi, all

Current -tip tree(92c883a) fail to resume after suspend to mem.
Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).

commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
Author: Matthieu Castet <castet.matthieu@...e.fr>
Date:   Tue Nov 16 22:31:26 2010 +0100

    x86: Add NX protection for kernel data


I did some debug and found the regression is caused by below line.

-       set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
+       set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);

In my machine,
rodata_start=0xffffffff81a00000, end=0xffffffff81e00000, kernel_end=0xffffffff82200000

Without this commit, kernel page table dumps

---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000           2M     ro         PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000        1604K     ro             GLB NX pte
0xffffffff81d91000-0xffffffff81e00000         444K     ro             GLB NX pte
0xffffffff81e00000-0xffffffff82000000           2M     RW         PSE GLB x  pmd
0xffffffff82000000-0xffffffff8200c000          48K     RW             GLB x  pte
0xffffffff8200c000-0xffffffff82100000         976K     RW             GLB x  pte
0xffffffff82100000-0xffffffff82200000           1M     RW             GLB x  pte
.....

With this commit, kernel page table dumps

---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000           2M     ro         PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000        1604K     ro             GLB NX pte
0xffffffff81d91000-0xffffffff81e00000         444K     ro             GLB NX pte
0xffffffff81e00000-0xffffffff82000000           2M     RW         PSE GLB NX pmd
0xffffffff82000000-0xffffffff8200c000          48K     RW             GLB NX pte
0xffffffff8200c000-0xffffffff82100000         976K     RW             GLB NX pte
0xffffffff82100000-0xffffffff82200000           1M     RW             GLB NX pte
.....

The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.

I guess this range code is used by resume wakeup code. So setting it to NX causes problem.

Any idea?

Thanks,
Lin Ming


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/