Re: Wrong module .text address in 4.16.0

From: Christian Borntraeger
Date: Mon Apr 16 2018 - 02:24:09 EST


FWIW, this breaks at least perf capability to resolve module symbols.
Adding some more CCs for perf and module.


On 04/16/2018 07:51 AM, Thomas-Mich Richter wrote:
> I just installed 4.16.0 and discovered the module .text address is
> wrong. It happens on s390 and x86 platforms. I have not tested others.
>
> Here is the issue, I have used module qeth_l2 on s390 which is the
> ethernet device driver:
>
> root@s35lp76 ~]# lsmod
> Module Size Used by
> qeth_l2 94208 1
> ...
>
> [root@s35lp76 ~]# cat /proc/modules | egrep '^qeth_l2'
> qeth_l2 94208 1 - Live 0x000003ff80401000 <---- This is the correct address in memory
> [root@s35lp76 ~]# cat /sys/module/qeth_l2/sections/.text
> 0x0000000018ea8363 <---- This is the wrong address
> [root@s35lp76 ~]#
>
> File /sys/module/qeth_l2/sections/.text displays a very strange
> address which is definitely wrong. It should be something like
> 0x000003ff80401xxx.
>
> Same on x86.
>
> I have checked file kernel/module.c function add_sect_attrs()
> and it calls module_sect_show() when the sysfs file is read.
> And module_sect_show() uses
>
> sprintf(buf, "0x%pK\n", (void *)sattr->address);
>
> and my sysctl setting should be correct:
> [root@s35lp76 linux]# sysctl -a | fgrep kernel.kptr_restrict
> kernel.kptr_restrict = 0
> [root@s35lp76 linux]#
>
> I wonder if somebody else has seen this issue?
> Ideas how to fix this?
>
> Thanks
>