On Sun, Sep 29, 2019 at 11:43:38PM +0900, Tetsuo Handa wrote:
On 2019/09/29 22:54, Greg Kroah-Hartman wrote:
From: Waiman Long <longman@xxxxxxxxxx>
[ Upstream commit 513e1073d52e55b8024b4f238a48de7587c64ccf ]
Tetsuo Handa had reported he saw an incorrect "downgrading a read lock"
warning right after a previous lockdep warning. It is likely that the
previous warning turned off lock debugging causing the lockdep to have
inconsistency states leading to the lock downgrade warning.
Fix that by add a check for debug_locks at the beginning of
__lock_downgrade().
Please drop "[PATCH 4.19 36/63] locking/lockdep: Add debug_locks check in __lock_downgrade()".
We had a revert patch shown below in the past.
We had a revert in the stable trees, but that revert was incorrect.
Take a look at commit 513e1073d52e55 upstream, it patches
__lock_set_class() (even though the subject line says
__lock_downgrade()). So this is not a backporting error as the revert
said it is, but is rather the intended location to be patched.
If this is actually wrong, then it should be addressed upstream first.
--
Thanks,
Sasha
