On Tue, Mar 14, 2023 at 04:23:54PM +0200, Jarkko Sakkinen wrote:
> > diff --git a/drivers/char/random.c b/drivers/char/random.c
> > index ce3ccd172cc8..708110c780aa 100644
> > --- a/drivers/char/random.c
> > +++ b/drivers/char/random.c
> > @@ -934,20 +934,20 @@ EXPORT_SYMBOL(add_device_randomness);
> > void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy, bool sleep_after)
> > {
> > mix_pool_bytes(buf, len);
> > credit_init_bits(entropy);
> >
> > /*
> > * Throttle writing to once every reseed interval, unless we're not yet
> > * initialized or no entropy is credited.
> > */
> > - if (sleep_after && !kthread_should_stop() && (crng_ready() || !entropy))
> > - schedule_timeout_interruptible(crng_reseed_interval());
> > +// if (sleep_after && !kthread_should_stop() && (crng_ready() || !entropy))
> > +// schedule_timeout_interruptible(crng_reseed_interval());
> > }
> > EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
> >
> > /*
> > * Handle random seed passed by bootloader, and credit it depending
> > * on the command line option 'random.trust_bootloader'.
> > */
> > void __init add_bootloader_randomness(const void *buf, size_t len)
> > {
> >
> > Then I hooked the tpm emulator up to qemu and put it in tpm1 mode. I had
> > userspace `echo mem > /sys/power/state` every couple of seconds (or
> > continuously maybe?), and then I used the qemu monitor interface to wake
> > the system from sleep. And kaboom.
>
> Thanks for the tips! I'll try various patch combinations and see what
> happens.
I created a VM using libvirt with the following configuration [*]
<tpm model='tpm-tis'>
<backend type='emulator' version='1.2'/>
<alias name='tpm0'/>
</tpm>
I do not have issues with suspend so far with unmodified v6.3-rc7.
It would be nice to have a script that gives a guaranteed crash with
unmodified kernel even if run for some hours.
Instead of using QEMU monitor interface and /sys/power/state, I wonder
if a stress test could be based on looping rtcwake for easier comparison
of results?
[*] full description: https://gist.github.com/jarkkojs/66ea0d8d6a927311e8abb8b35e1ddbcd
BR, Jarkko
