Re: [bug report][stable] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)

[Joseph Qi]

Hi Nadav,
Thanks for the comments.
I'll test the 3 patches in the mentioned thread.

Thanks,
Joseph

On 19/6/8 00:38, Nadav Amit wrote:
>> On Jun 7, 2019, at 3:24 AM, Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx> wrote:
>>
>> Hi all,
>> Any idea on this regression? 
> 
> Sorry for the late response (I assumed, for some reason, that you also follow 
> the second thread about this issue).
> 
> Anyhow, it should be fixed by backporting some patches which were mistakenly
> missed.
> 
> See https://lore.kernel.org/stable/20190606131558.GJ29739@sasha-vm/
> 
> Regards,
> Nadav
> 
> 
>> Thanks,
>> Joseph
>>
>> On 19/6/5 18:23, Joseph Qi wrote:
>>> Hi,
>>>
>>> I have encountered a kernel BUG when running ltp ftrace-stress-test
>>> on 4.19.48.
>>>
>>> [  209.704855] LTP: starting ftrace-stress-test (ftrace_stress_test.sh 90)
>>> [  209.739412] Scheduler tracepoints stat_sleep, stat_iowait, stat_blocked and stat_runtime require the kernel parameter schedstats=enable or kernel.sched_schedstats=1
>>> [  212.054506] kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
>>> [  212.055595] BUG: unable to handle kernel paging request at ffffffffc0349000
>>> [  212.056589] PGD d00c067 P4D d00c067 PUD d00e067 PMD 23673e067 PTE 800000023457f061
>>> [  212.057759] Oops: 0011 [#1] SMP PTI
>>> [  212.058303] CPU: 0 PID: 0 Comm: swapper/0 Kdump: loaded Not tainted 4.19.48 #112
>>>
>>> After some investigation I have found that it is introduced by commit
>>> 8715ce033eb3 ("x86/modules: Avoid breaking W^X while loading modules"),
>>> and then revert this commit the issue is gone.
>>>
>>> I have also tested the same case on 5.2-rc3 as well as right at
>>> upstream commit f2c65fb3221a ("x86/modules: Avoid breaking W^X while
>>> loading modules"), which has been merged in 5.2-rc1, it doesn't
>>> happen.
>>>
>>> So I don't know why only stable has this issue while upstream doesn't.
>>>
>>> Thanks,
>>> Joseph
>