Re: [PATCH V7 5/7] cpufreq: Register notifiers with the PM QoS framework

[Viresh Kumar]

On 22-09-19, 23:12, Dmitry Osipenko wrote:
> This patch causes use-after-free on a cpufreq driver module reload. Please take a look, thanks in advance.
> 
> 
> [   87.952369] ==================================================================
> [   87.953259] BUG: KASAN: use-after-free in notifier_chain_register+0x4f/0x9c
> [   87.954031] Read of size 4 at addr e6abbd0c by task modprobe/243

Hi Dmitry,

I tried to reproduce it on my ubuntu on ARM64 setup and I couldn't hit
these issues on v5.4-rc1 with Kasan built in.

I then enabled Kasan (tried both inline and outline instrumentation)
but I couldn't get past the issues with module insertion. It fails
like this for me:

root@linaro-developer:~/work# insmod cpufreq-dt.ko 
[   72.985974] cpufreq_dt: Unknown symbol __asan_report_load1_noabort (err -2)
[   72.993164] cpufreq_dt: Unknown symbol __asan_report_load4_noabort (err -2)
[   73.000307] cpufreq_dt: Unknown symbol __asan_report_load8_noabort (err -2)
[   73.007451] cpufreq_dt: Unknown symbol __asan_report_store1_noabort (err -2)
[   73.014643] cpufreq_dt: Unknown symbol __asan_register_globals (err -2)
[   73.021409] cpufreq_dt: Unknown symbol __asan_unregister_globals (err -2)
[   73.028349] cpufreq_dt: Unknown symbol __asan_report_store8_noabort (err -2)
[   73.035543] cpufreq_dt: Unknown symbol __asan_report_store4_noabort (err -2)
insmod: ERROR: could not insert module cpufreq-dt.ko: Unknown symbol in module

I tried to search for these errors but couldn't find why I am getting
these and why the symbols are missing here. Can you suggest something
here ?

-- 
viresh