On Thu, Oct 25, 2018 at 10:16:08AM -0400, Sasha Levin wrote:
From: Jiri Kosina jkosina@suse.cz
[ Upstream commit 838fe1887765f4cc679febea60d87d2a06bd300e ]
cleaner_kthread() is not marked freezable, and therefore calling try_to_freeze() in its context is a pointless no-op.
In addition to that, as has been clearly demonstrated by 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()"), it's perfectly valid / legal for cleaner_kthread() to stay scheduled out in an arbitrary place during suspend (in that particular example that was waiting for reading of extent pages), so there is no need to leave any traces of freezer in this kthread.
Fixes: 80ad623edd2d ("Revert "btrfs: clear PF_NOFREEZE in cleaner_kthread()") Fixes: 696249132158 ("btrfs: clear PF_NOFREEZE in cleaner_kthread()") Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org
IIRC it was some preparatory work for livepatching. I did a quick check if this is safe for 4.4 and would say yes, but the patch does not fix anything so IMO this does not need to go to stable.