Re: x86/mm: Found insecure W+X mapping

Re: x86/mm: Found insecure W+X mapping

[Denis Kirjanov]

On 11/7/15, Denis Kirjanov <kda@linux-powerpc.org> wrote:
> Hi,
>
> kernel v4.3-3155-g1b1050c,
> found the following WARNING at boot time:
>
> [   15.363908] Freeing unused kernel memory: 628K (ffff880001963000 -
> ffff880001a00000)
> [   15.370510] Freeing unused kernel memory: 1744K (ffff880001e4c000 -
> ffff880002000000)
> [   15.380507] ------------[ cut here ]------------
> [   15.380746] WARNING: CPU: 4 PID: 1 at
> arch/x86/mm/dump_pagetables.c:225 note_page+0x619/0x7e0()
> [   15.381208] x86/mm: Found insecure W+X mapping at address
> ffffffffa0000000/0xffffffffa0000000
> [   15.381615] Modules linked in:
> [   15.381907] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 4.3.0+ #3
> [   15.382163] Hardware name: IBM BladeCenter HS22 -[7870AC1]-/68Y8027
>     , BIOS -[P9E131AUS-1.05]- 10/18/2009
> [   15.382569]  ffffffff81d29017 ffff880663607d60 ffffffff81334959
> ffff880663607da8
> [   15.383222]  ffff880663607d98 ffffffff81059a11 ffff880661fd9010
> 0000000000000004
> [   15.383850]  0000000000000000 ffff880663607e98 0000000000000000
> ffff880663607df8
> [   15.384531] Call Trace:
> [   15.384763]  [<ffffffff81334959>] dump_stack+0x4b/0x72
> [   15.384996]  [<ffffffff81059a11>] warn_slowpath_common+0x81/0xc0
> [   15.385289]  [<ffffffff81059a97>] warn_slowpath_fmt+0x47/0x50
> [   15.385562]  [<ffffffff810521c9>] note_page+0x619/0x7e0
> [   15.385793]  [<ffffffff8105269a>] ptdump_walk_pgd_level_core+0x30a/0x3b0
> [   15.386045]  [<ffffffff81052762>]
> ptdump_walk_pgd_level_checkwx+0x12/0x20
> [   15.386284]  [<ffffffff81048f69>] mark_rodata_ro+0xe9/0xf0
> [   15.386520]  [<ffffffff8194e040>] ? rest_init+0x140/0x140
> [   15.386752]  [<ffffffff8194e058>] kernel_init+0x18/0xe0
> [   15.386986]  [<ffffffff8195b6ff>] ret_from_fork+0x3f/0x70
> [   15.387240]  [<ffffffff8194e040>] ? rest_init+0x140/0x140
> [   15.387472] ---[ end trace efbf79af9fce1389 ]---
> [   15.387727] x86/mm: Checked W+X mappings: FAILED, 2 W+X pages found.
>