On Fri, 30 Sep 2016 11:50:34 +0300 Andrey Ryabinin [off-list ref] wrote:

It could be not possible to freeze coredumping task when it waits
for 'core_state->startup' completion, because threads are frozen
in get_signal() before they got a chance to complete 'core_state->startup'.

Use freezer_do_not_count() to tell freezer to ignore coredumping
task while it waits for core_state->startup completion.

Signed-off-by: Andrey Ryabinin <redacted>
Cc: stable@vger.kernel.org

The changelog provides no reason why this patch should be merged into
-stable.  Nor into anything else, really.

Please (as always) provide a full description of the bug's end-user
visible effects.