locking/ww_mutex/test: Make sure we bail out instead of livelock
authorJohn Stultz <jstultz@google.com>
Fri, 22 Sep 2023 04:36:01 +0000 (04:36 +0000)
committerIngo Molnar <mingo@kernel.org>
Fri, 22 Sep 2023 07:43:41 +0000 (09:43 +0200)
commitcfa92b6d52071aaa8f27d21affdcb14e7448fbc1
treee0d91a4be542da4cd17319f316e8e18dc12d6b48
parentbccdd808902f8c677317cec47c306e42b93b849e
locking/ww_mutex/test: Make sure we bail out instead of livelock

I've seen what appears to be livelocks in the stress_inorder_work()
function, and looking at the code it is clear we can have a case
where we continually retry acquiring the locks and never check to
see if we have passed the specified timeout.

This patch reworks that function so we always check the timeout
before iterating through the loop again.

I believe others may have hit this previously here:

  https://lore.kernel.org/lkml/895ef450-4fb3-5d29-a6ad-790657106a5a@intel.com/

Reported-by: Li Zhijian <zhijianx.li@intel.com>
Signed-off-by: John Stultz <jstultz@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230922043616.19282-4-jstultz@google.com
kernel/locking/test-ww_mutex.c