Re: [PATCH 5.15 v3 08/16] x86/alternative: Optimize returns patching

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
ℹ️ This is part 08/16 of a series
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: d2408e043e7296017420aa5929b3bba4d5e61013

WARNING: Author mismatch between patch and upstream commit:
Backport author: Pawan Gupta<pawan.kumar.gupta@linux.intel.com>
Commit author: Borislav Petkov (AMD)<bp@alien8.de>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (different SHA1: 3de55fa8eadb)

Found fixes commits:
4ba89dd6ddec x86/alternatives: Remove faulty optimization

Note: The patch differs from the upstream commit:
---
1:  d2408e043e729 ! 1:  94c28300c096e x86/alternative: Optimize returns patching
    @@ Metadata
      ## Commit message ##
         x86/alternative: Optimize returns patching
     
    +    commit d2408e043e7296017420aa5929b3bba4d5e61013 upstream.
    +
         Instead of decoding each instruction in the return sites range only to
         realize that that return site is a jump to the default return thunk
         which is needed - X86_FEATURE_RETHUNK is enabled - lift that check
    @@ Commit message
         Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
         Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
         Link: https://lore.kernel.org/r/20230512120952.7924-1-bp@alien8.de
    +    Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
     
      ## arch/x86/kernel/alternative.c ##
     @@ arch/x86/kernel/alternative.c: static int patch_return(void *addr, struct insn *insn, u8 *bytes)
---

NOTE: These results are for this patch alone. Full series testing will be
performed when all parts are received.

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |