+ kfence-avoid-passing-g-for-test.patch added to mm-hotfixes-unstable branch

+ kfence-avoid-passing-g-for-test.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: kfence: avoid passing -g for test
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     kfence-avoid-passing-g-for-test.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/kfence-avoid-passing-g-for-test.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Marco Elver <elver@google.com>
Subject: kfence: avoid passing -g for test
Date: Thu, 16 Mar 2023 23:47:04 +0100

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5:

  $ make -skj"$(nproc)" ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- \
			LLVM=1 LLVM_IAS=0 O=build \
			mrproper allmodconfig mm/kfence/kfence_test.o
  /tmp/kfence_test-08a0a0.s: Assembler messages:
  /tmp/kfence_test-08a0a0.s:14627: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14628: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14632: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14633: Error: non-constant .uleb128 is not supported
  /tmp/kfence_test-08a0a0.s:14639: Error: non-constant .uleb128 is not supported
  ...

This is because `-g` defaults to the compiler debug info default.  If the
assembler does not support some of the directives used, the above errors
occur.  To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that.  (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-1-elver@google.com
Fixes: bc8fbc5f305a ("kfence: add test suite")
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/mm/kfence/Makefile~kfence-avoid-passing-g-for-test
+++ a/mm/kfence/Makefile
@@ -2,5 +2,5 @@
 
 obj-y := core.o report.o
 
-CFLAGS_kfence_test.o := -g -fno-omit-frame-pointer -fno-optimize-sibling-calls
+CFLAGS_kfence_test.o := -fno-omit-frame-pointer -fno-optimize-sibling-calls
 obj-$(CONFIG_KFENCE_KUNIT_TEST) += kfence_test.o
_

Patches currently in -mm which might be from elver@google.com are

kasan-powerpc-dont-rename-memintrinsics-if-compiler-adds-prefixes.patch
kfence-avoid-passing-g-for-test.patch
kcsan-avoid-passing-g-for-test.patch
kfence-kcsan-avoid-passing-g-for-tests.patch