Re: [PATCH RESEND] powerpc/tools: drop `-o pipefail` in gcc check scripts

On Mon, Nov 10, 2025 at 12:33 PM Christophe Leroy
[off-list ref] wrote:

Le 30/10/2025 à 19:09, Jan Stancek a écrit :

quoted

On Mon, Oct 6, 2025 at 10:19 PM Justin Forbes [off-list ref] wrote:

quoted

On Tue, Sep 23, 2025 at 9:31 AM Jan Stancek [off-list ref] wrote:

quoted

We've been observing rare non-deterministic kconfig failures during
olddefconfig, where ARCH_USING_PATCHABLE_FUNCTION_ENTRY was getting
disabled and with it number of other config options that depend on it.

The reason is that gcc-check-fpatchable-function-entry.sh can fail
if `grep -q` (or scripts/dummy-tools/gcc) is fast enough to exit while
there is still someone writing on other side of pipe. `pipefail`
propagates that error up to kconfig.

This can be seen for example with:
   # (set -e; set -o pipefail; yes | grep -q y); echo $?
   141

or by running the actual check script in loop extensively:
   ----------------------------- 8< -------------------------------
   function kconfig()
   {
     for i in `seq 1 100`; do
       arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh \
         ./scripts/dummy-tools/gcc -mlittle-endian \
         || { echo "Oops"; exit 1; }
     done
   }

   for ((i=0; i<$(nproc); i++)); do kconfig & done
   wait; echo "Done"
   ----------------------------- >8 -------------------------------

Fixes: 0f71dcfb4aef ("powerpc/ftrace: Add support for -fpatchable-function-entry")
Fixes: b71c9ffb1405 ("powerpc: Add arch/powerpc/tools directory")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
  arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh | 1 -
  arch/powerpc/tools/gcc-check-mprofile-kernel.sh           | 1 -
  2 files changed, 2 deletions(-)

diff --git a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
index 06706903503b..baed467a016b 100755
--- a/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh
+++ b/arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh

@@ -2,7 +2,6 @@
  # SPDX-License-Identifier: GPL-2.0

  set -e
-set -o pipefail

  # To debug, uncomment the following line
  # set -x

diff --git a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
index 73e331e7660e..6193b0ed0c77 100755
--- a/arch/powerpc/tools/gcc-check-mprofile-kernel.sh
+++ b/arch/powerpc/tools/gcc-check-mprofile-kernel.sh

@@ -2,7 +2,6 @@
  # SPDX-License-Identifier: GPL-2.0

  set -e
-set -o pipefail

  # To debug, uncomment the following line
  # set -x
--

2.47.1

Would love to see this picked up, it fixes a problem we have run into
with our CI.

Tested-by: Justin M. Forbes <redacted>

Thanks Justin.

Would any maintainers also care to review? Ty.

Is the problem only with those scripts ? I see other scripts using
pipefail in the kernel:

As far as kconfig goes, we've observed this issue only with the two
gcc-check scripts.

arch/powerpc/tools/gcc-check-fpatchable-function-entry.sh:set -o pipefail
arch/powerpc/tools/gcc-check-mprofile-kernel.sh:set -o pipefail
drivers/gpu/drm/ci/dt-binding-check.sh:set -euxo pipefail
drivers/gpu/drm/ci/dtbs-check.sh:set -euxo pipefail
drivers/gpu/drm/ci/kunit.sh:set -euxo pipefail
drivers/gpu/drm/ci/setup-llvm-links.sh:set -euo pipefail
scripts/check-uapi.sh:set -o pipefail

Christophe