Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@xxxxxxxxxxxxxx/ Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Reviewed-by: Nicolas Schier <nicolas@xxxxxxxxx> Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> # LLVM-14 (x86-64) --- Changes in v7: - Add comment to the code scripts/Makefile.build | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 014ebee70fd6..31feb798e16e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -274,8 +274,10 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE $(call if_changed_rule,cc_o_c) $(call cmd,force_checksrc) -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \ - $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@ +# To make this rule robust against "Argument list too long" error, +# ensure to add $(obj)/ prefix by a shell command. +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \ + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE $(call if_changed,mod) -- 2.32.0
