Subject: linux-next: build failure after merge of the tip tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 18 Oct 2021 17:23:30 +1100

Hi all,

After merging the tip tree, today's linux-next build (x86_64 allnoconfig)
failed like this:

arch/x86/kernel/process.c: In function '__get_wchan':
arch/x86/kernel/process.c:950:2: error: implicit declaration of function 'stack_trace_save_tsk' [-Werror=implicit-function-declaration]
  950 |  stack_trace_save_tsk(p, &entry, 1, 0);
      |  ^~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

Caused by commit

  bc9bbb81730e ("x86: Fix get_wchan() to support the ORC unwinder")

stack_trace_save_tsk() requires CONFIG_STACKTRACE which is not set for
this build.

I have reverted that commit, and commit

  42a20f86dc19 ("sched: Add wrapper for get_wchan() to keep task blocked")

which follows it, for today.

-- 
Cheers,
Stephen Rothwell