tree 6473938e7b80fffad24d9b7fb63a7f884428407a
parent 6a7c0215d28c6ec1482d3aa5bf28d88c2070f426
author Douglas Anderson <dianders@chromium.org> 1543981108 -0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1549997239 +0100

kdb: Don't back trace on a cpu that didn't round up

[ Upstream commit 162bc7f5afd75b72acbe3c5f3488ef7e64a3fe36 ]

If you have a CPU that fails to round up and then run 'btc' you'll end
up crashing in kdb becaue we dereferenced NULL.  Let's add a check.
It's wise to also set the task to NULL when leaving the debugger so
that if we fail to round up on a later entry into the debugger we
won't backtrace a stale task.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>