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

[Christophe Leroy]

Le 30/10/2025 à 19:09, Jan Stancek a écrit :
> On Mon, Oct 6, 2025 at 10:19 PM Justin Forbes <jforbes@xxxxxxxxxxxxxxxxx> wrote:
> > On Tue, Sep 23, 2025 at 9:31 AM Jan Stancek <jstancek@xxxxxxxxxx> wrote:
> > > 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@xxxxxxxxxx>
> > > Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
> > > Signed-off-by: Jan Stancek <jstancek@xxxxxxxxxx>
> > > ---
> > >   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 <jforbes@xxxxxxxxxxxxxxxxx>
>
> 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:

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