Re: [PATCH] livepatch: klp_send_signal should treat PF_IO_WORKER like PF_KTHREAD

On 3/25/21 5:26 AM, Miroslav Benes wrote:

On Thu, 25 Mar 2021, Dong Kai wrote:

quoted

commit 15b2219facad ("kernel: freezer should treat PF_IO_WORKER like
PF_KTHREAD for freezing") is to fix the freezeing issue of IO threads
by making the freezer not send them fake signals.

Here live patching consistency model call klp_send_signals to wake up
all tasks by send fake signal to all non-kthread which only check the
PF_KTHREAD flag, so it still send signal to io threads which may lead to
freezeing issue of io threads.

I suppose this could happen, but it will also affect the live patching
transition if the io threads do not react to signals.

Are you able to reproduce it easily? I mean, is there a testcase I could
use to take a closer look?
  

If repro is only hypothetical at this point, perhaps we can artificially 
create it in selftests?  And useful to verify the future change you 
mentioned in your other reply?

-- Joe