gpu: nvgpu: stop timer on failing channel

In gk20a_channel_timeout_handler(), below deadlock scenario
is possible :

thread 1:
- take global lock g->ch_wdt_lock
- identify timed out channel (as ch1)
- check engine status which is stuck
- identify failing channel on engine as ch2
- we need to trigger recovery with ch2
- as part of recovery, call channel_abort() for ch2
- in channel_abort(), we wait to cancel the timer wq
- but timer wq for ch2 never completes due to thread 2

thread 2:
- ch2 has already timed out
- to process, we wait for global lock g->ch_wdt_lock
- this lock needs to be released by thread 1

To fix this, cancel the timer (through flag) of ch2
(failing channel on engine) before triggering recovery
on that channel

Bug 200164753

Change-Id: Idb42d01c8440a53f43cb5e87e41f1c283f7e8fcf
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/929924
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Tested-by: Terje Bergstrom <tbergstrom@nvidia.com>

0 files changed, 0 insertions, 0 deletions