Re: [PATCH 5.15.y 1/4] x86: Fix get_wchan() to support the ORC unwinder

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: bc9bbb81730ea667c31c5b284f95ee312bab466f

WARNING: Author mismatch between patch and upstream commit:
Backport author: Siddhi Katage <siddhi.katage@oracle.com>
Commit author: Qi Zheng <zhengqi.arch@bytedance.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)

Found fixes commits:
5d1ceb3969b6 x86: Fix __get_wchan() for !STACKTRACE

Note: The patch differs from the upstream commit:
---
1:  bc9bbb81730e ! 1:  1f7a2f87bdde x86: Fix get_wchan() to support the ORC unwinder
    @@ Metadata
      ## Commit message ##
         x86: Fix get_wchan() to support the ORC unwinder
     
    +    [ Upstream commit bc9bbb81730ea667c31c5b284f95ee312bab466f ]
    +
         Currently, the kernel CONFIG_UNWINDER_ORC option is enabled by default
         on x86, but the implementation of get_wchan() is still based on the frame
         pointer unwinder, so the /proc/<pid>/wchan usually returned 0 regardless
    @@ Commit message
         Signed-off-by: Kees Cook <keescook@chromium.org>
         Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
         Link: https://lkml.kernel.org/r/20211008111626.271115116@infradead.org
    +    Signed-off-by: Siddhi Katage <siddhi.katage@oracle.com>
     
      ## arch/x86/kernel/process.c ##
     @@ arch/x86/kernel/process.c: unsigned long arch_randomize_brk(struct mm_struct *mm)

---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| 5.15                      | Success     | Success    |