Re: [PATCH] tools/build: make in-target rule robust against too long argument error

[Changqing Li]

Hi, Ian

Kindly ping.  Could you reproduce it?  Any comments?

Regards

Changqing

On 8/19/25 11:01, Changqing Li wrote:
> On 8/19/25 04:38, Ian Rogers wrote:
> > CAUTION: This email comes from a non Wind River email account!
> > Do not click links or open attachments unless you recognize the 
> > sender and know the content is safe.
> >
> > On Mon, Jul 28, 2025 at 2:31 AM <changqing.li@xxxxxxxxxxxxx> wrote:
> > > From: Changqing Li <changqing.li@xxxxxxxxxxxxx>
> > >
> > > The command length of in-target scales with the depth of the directory
> > > times the number of objects in the Makefile. When there are many
> > > objects, and O=[absolute_path] is set, and the absolute_path is
> > > relatively long. It is possile that this line "$(call
> > > if_changed,$(host)ld_multi)" will report error:
> > > "make[4]: /bin/sh: Argument list too long"
> > >
> > > For example, build perf tools with O=/long/output/path
> > >
> > > Like built-in.a and *.mod rules in scripts/Makefile.build, add
> > > $(objpredix)/ by the shell command instead of by Make's builtin
> > > function.
> > >
> > > Signed-off-by: Changqing Li <changqing.li@xxxxxxxxxxxxx>
> > Thanks Changqing, the change makes sense to me. The printf is pushing
> > the values into xargs rather than using $^ with ld. I've tried
> > reproducing the error to test your fix by creating long directory
> > names in /tmp and then passing them to O=. I've not been able to do
> > this. Could you send a reproduction for me to test?
> >
> > Thanks,
> > Ian
>
> Hi, Ian
>
> Thanks. Here is my steps:
>
> 1. git clone https://github.com/torvalds/linux.git
>
> 2. cd linux/tools/perf/
>
> 3. mkdir 
> /tmp/01234567890123456789/0123456789012345678901234567890123456789/0123456789012345678901234567890123456789/012345678901234567890123456789/01234567890123456789/012345678901234567890123456789/01234567890123456789012345678/9012345678901234567890123456789/012345678901234567890123456789/012345678901234567890123456789/01234567890123456789012345678901234567890123456789012345678901234567890123/perf-1.0
>
> 4.  make NO_LIBTRACEEVENT=1 
> O=/tmp/01234567890123456789/0123456789012345678901234567890123456789/0123456789012345678901234567890123456789/012345678901234567890123456789/01234567890123456789/012345678901234567890123456789/01234567890123456789012345678/9012345678901234567890123456789/012345678901234567890123456789/012345678901234567890123456789/01234567890123456789012345678901234567890123456789012345678901234567890123/perf-1.0 
>
>
> 5. Above step failed with error:
>
> make[4]: /bin/sh: Argument list too long
>
> make[4]: *** [/buildarea2/cli10/tmp/linux/tools/build/Makefile.build 
> <https://urldefense.com/v3/__http://Makefile.build__;!!AjveYdw8EvQ!c2n7zPX4Vrhwd7a9UxsjCXBGO5V8Llmon1egvupz4kHL4869ilesQgRgQZO8nj8AWwQJUlY9DOoWPD688quA73jNugR6IZRxy09Eig$>:148: 
> /tmp/01234567890123456789/0123456789012345678901234567890123456789/0123456789012345678901234567890123456789/012345678901234567890123456789/01234567890123456789/012345678901234567890123456789/01234567890123456789012345678/9012345678901234567890123456789/012345678901234567890123456789/012345678901234567890123456789/01234567890123456789012345678901234567890123456789012345678901234567890123/perf-1.0/util/perf-util-in.o] 
> Error 127
>
> make[3]: *** [/buildarea2/cli10/tmp/linux/tools/build/Makefile.build 
> <https://urldefense.com/v3/__http://Makefile.build__;!!AjveYdw8EvQ!c2n7zPX4Vrhwd7a9UxsjCXBGO5V8Llmon1egvupz4kHL4869ilesQgRgQZO8nj8AWwQJUlY9DOoWPD688quA73jNugR6IZRxy09Eig$>:142: 
> util] Error 2
>
> make[2]: *** [Makefile.perf:797: 
> /tmp/01234567890123456789/0123456789012345678901234567890123456789/0123456789012345678901234567890123456789/012345678901234567890123456789/01234567890123456789/012345678901234567890123456789/01234567890123456789012345678/9012345678901234567890123456789/012345678901234567890123456789/012345678901234567890123456789/01234567890123456789012345678901234567890123456789012345678901234567890123/perf-1.0/perf-util-in.o] 
> Error 2
>
>
> Regards
>
> Changqing
> > > ---
> > >   tools/build/Makefile.build | 6 ++++--
> > >   1 file changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
> > > index 3584ff308607..39066a3ef2fc 100644
> > > --- a/tools/build/Makefile.build
> > > +++ b/tools/build/Makefile.build
> > > @@ -70,11 +70,13 @@ quiet_cmd_gen = GEN     $@
> > >   # If there's nothing to link, create empty $@ object.
> > >   quiet_cmd_ld_multi = LD      $@
> > >         cmd_ld_multi = $(if $(strip $(obj-y)),\
> > > -                     $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f 
> > > $@; $(AR) rcs $@)
> > > +                     printf "$(objprefix)%s " $(patsubst 
> > > $(objprefix)%,%,$(filter $(obj-y),$^)) | \
> > > +                     xargs $(LD) -r -o $@,rm -f $@; $(AR) rcs $@)
> > >
> > >   quiet_cmd_host_ld_multi = HOSTLD  $@
> > >         cmd_host_ld_multi = $(if $(strip $(obj-y)),\
> > > -                          $(HOSTLD) -r -o $@  $(filter 
> > > $(obj-y),$^),rm -f $@; $(HOSTAR) rcs $@)
> > > +                          printf "$(objprefix)%s " $(patsubst 
> > > $(objprefix)%,%,$(filter $(obj-y),$^)) | \
> > > +                          xargs $(HOSTLD) -r -o $@,rm -f $@; 
> > > $(HOSTAR) rcs $@)
> > >
> > >   ifneq ($(filter $(obj),$(hostprogs)),)
> > >     host = host_
> > > --
> > > 2.34.1