[PATCH v4 0/2] rcu: Display registers of self-detected stall as far as possible

[Zhen Lei <thunder.leizhen@huawei.com>]

v3 --> v4:
1. To avoid undo/redo, merge patch 1-2 in v3 into one.

v2 --> v3:
1. Patch 1 Add trigger_single_cpu_backtrace(cpu) in synchronize_rcu_expedited_wait()
   Subsequently, we can see that all callers of dump_cpu_task() try
   trigger_single_cpu_backtrace() first. Then I do the cleanup in Patch 2.
2. Patch 3, as Paul E. McKenney's suggestion, push the code into dump_cpu_task().

For newcomers:
Currently, dump_cpu_task() is mainly used by RCU, in order to dump the
stack traces of the current task of the specified CPU when a rcu stall
is detected.

For architectures that do not support NMI interrupts, registers is not
printed when rcu stall is self-detected. This patch series improve it.


v2:
https://lkml.org/lkml/2022/7/27/1800

Zhen Lei (2):
  sched/debug: Try trigger_single_cpu_backtrace(cpu) in dump_cpu_task()
  sched/debug: Show the registers of 'current' in dump_cpu_task()

 kernel/rcu/tree_stall.h |  8 +++-----
 kernel/sched/core.c     | 14 ++++++++++++++
 kernel/smp.c            |  3 +--
 3 files changed, 18 insertions(+), 7 deletions(-)

-- 
2.25.1