[bug #63818] V=1 stopped working for Linux kernel module builds with make-4.4

[Martin Dorey]

URL:
  <https://savannah.gnu.org/bugs/?63818>

                 Summary: V=1 stopped working for Linux kernel module builds
with make-4.4
                   Group: make
               Submitter: mdorey
               Submitted: Sun 19 Feb 2023 11:59:36 AM PST
                Severity: 3 - Normal
              Item Group: Documentation
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
       Component Version: 4.4
        Operating System: POSIX-Based
           Fixed Release: None
           Triage Status: None


    _______________________________________________________

Follow-up Comments:


-------------------------------------------------------
Date: Sun 19 Feb 2023 11:59:36 AM PST By: Martin Dorey <mdorey>
As reported by Jan Palus in
https://lists.gnu.org/archive/html/bug-make/2022-11/msg00185.html with the
diagnosis polished by Paul in reply, the Linux kernel build system goes into
silent mode, stopping V=1 from telling you eg about the compiler commands,
with make-4.4 (but not earlier), if an s is present in certain parts of the
command line.  When compiling modules, this is more likely than it might seem,
because an argument of the form M=$(CURDIR) is given to make and s is common
in directory names.

This was fixed in the Linux kernel build system by Dmitry with help from
Masahiro Yamada for v6.2-rc1
(https://github.com/torvalds/linux/commit/4bf73588165ba7d32131a043775557a54b6e1db5).
 I think the problem arrived with v4.13-rc1
(https://github.com/torvalds/linux/commit/6f0fa58e459642b16901521cc58ac474b787ec5b).
 To put that in Debian terms, that means that Buster, Bullseye and (likely)
Bookworm are afflicted.

Here's a complete example, derived from https://sysprog21.github.io/lkmpg/ but
with the Makefile simplified the way I would have written it and a stray quote
left deliberately at the end of the .c file:


martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$ cat Makefile
obj-m += hello-1.o 
        
KVERSION ?= $(shell uname -r)
KVERSION := $(KVERSION)
        
TARGETS = modules clean
.PHONY: $(TARGETS)
$(TARGETS): %:; $(MAKE) -C /lib/modules/$(KVERSION)/build M=$(CURDIR) $@
martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$ cat hello-1.c 
/* 
 * hello-1.c - The simplest kernel module. 
 */ 
#include <linux/kernel.h> /* Needed for pr_info() */ 
#include <linux/module.h> /* Needed by all modules */ 
 
int init_module(void) 
{ 
    pr_info("Hello world 1.\n"); 
 
    /* A non 0 return means init_module failed; module can't be loaded. */ 
    return 0; 
} 
 
void cleanup_module(void) 
{ 
    pr_info("Goodbye world 1.\n"); 
} 
 
MODULE_LICENSE("GPL");
"
martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$ 


This is what the problem looks like:


martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$
~/download/make-4.4/make V=1
/home/martind/download/make-4.4/make -C /lib/modules/4.19.0-21-amd64/build
M=/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s modules
make[1]: Entering directory '/usr/src/linux-headers-4.19.0-21-amd64'
/home/martind/download/make-4.4/make -C /usr/src/linux-headers-4.19.0-21-amd64
KBUILD_SRC=/usr/src/linux-headers-4.19.0-21-common \
-f /usr/src/linux-headers-4.19.0-21-common/Makefile modules
mkdir -p /home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/.tmp_versions ; rm
-f /home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/.tmp_versions/*
/home/martind/download/make-4.4/make -f
/usr/src/linux-headers-4.19.0-21-common/scripts/Makefile.build
obj=/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s
(cat /dev/null;   echo
kernel//home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.ko;) >
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/modules.order
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.c:21:1: warning:
missing terminating " character
 "
 ^
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.c:21:1: error:
missing terminating " character
make[4]: ***
[/usr/src/linux-headers-4.19.0-21-common/scripts/Makefile.build:315:
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.o] Error 1
make[3]: *** [/usr/src/linux-headers-4.19.0-21-common/Makefile:1561:
_module_/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s] Error 2
make[2]: *** [Makefile:146: sub-make] Error 2
make[1]: *** [Makefile:8: all] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-4.19.0-21-amd64'
make: *** [Makefile:8: modules] Error 2
martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$ 


The one new piece of information I want to present with this not-really-a-bug
report is the work around of adding quiet= to the command line, which then
adds the gcc line to the output:


martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$
~/download/make-4.4/make V=1 quiet=
/home/martind/download/make-4.4/make -C /lib/modules/4.19.0-21-amd64/build
M=/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s modules
make[1]: Entering directory '/usr/src/linux-headers-4.19.0-21-amd64'
/home/martind/download/make-4.4/make -C /usr/src/linux-headers-4.19.0-21-amd64
KBUILD_SRC=/usr/src/linux-headers-4.19.0-21-common \
-f /usr/src/linux-headers-4.19.0-21-common/Makefile modules
mkdir -p /home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/.tmp_versions ; rm
-f /home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/.tmp_versions/*
/home/martind/download/make-4.4/make -f
/usr/src/linux-headers-4.19.0-21-common/scripts/Makefile.build
obj=/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s
(cat /dev/null;   echo
kernel//home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.ko;) >
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/modules.order
   gcc-8
-Wp,-MD,/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/.hello-1.o.d
-nostdinc -isystem /usr/lib/gcc/x86_64-linux-gnu/8/include
-I/usr/src/linux-headers-4.19.0-21-common/arch/x86/include
-I./arch/x86/include/generated 
-I/usr/src/linux-headers-4.19.0-21-common/include -I./include
-I/usr/src/linux-headers-4.19.0-21-common/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi
-I/usr/src/linux-headers-4.19.0-21-common/include/uapi
-I./include/generated/uapi -include
/usr/src/linux-headers-4.19.0-21-common/include/linux/kconfig.h -include
/usr/src/linux-headers-4.19.0-21-common/include/linux/compiler_types.h 
-I/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s
-I/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s -D__KERNEL__ -Wall -Wundef
-Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common
-fshort-wchar -Werror-implicit-function-declaration -Werror=return-type
-Wno-format-security -std=gnu89 -fno-PIE -mno-sse -mno-mmx -mno-sse2
-mno-3dnow -mno-avx -fcf-protection=none -m64 -falign-jumps=1 -falign-loops=1
-mno-80387 -mno-fp-ret-in-387 -mpreferred-stack-boundary=3 -mskip-rax-setup
-mtune=generic -mno-red-zone -mcmodel=kernel -funit-at-a-time
-DCONFIG_X86_X32_ABI -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1
-DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -DCONFIG_AS_SSSE3=1
-DCONFIG_AS_CRC32=1 -DCONFIG_AS_AVX=1 -DCONFIG_AS_AVX2=1 -DCONFIG_AS_AVX512=1
-DCONFIG_AS_SHA1_NI=1 -DCONFIG_AS_SHA256_NI=1 -pipe -Wno-sign-compare
-fno-asynchronous-unwind-tables -mindirect-branch=thunk-extern
-mindirect-branch-register -fno-jump-tables -fno-delete-null-pointer-checks
-Wno-frame-address -Wno-format-truncation -Wno-format-overflow
-Wno-int-in-bool-context -O2 --param=allow-store-data-races=0
-Wframe-larger-than=2048 -fstack-protector-strong -Wno-unused-but-set-variable
-Wno-unused-const-variable -fno-var-tracking-assignments -g -pg
-mrecord-mcount -mfentry -DCC_USING_FENTRY -Wdeclaration-after-statement
-Wno-pointer-sign -Wno-stringop-truncation -Wno-array-bounds
-Wno-stringop-overflow -Wno-restrict -Wno-maybe-uninitialized
-fno-strict-overflow -fno-merge-all-constants -fmerge-constants
-fno-stack-check -fconserve-stack -Werror=implicit-int
-Werror=strict-prototypes -Werror=date-time -Werror=incompatible-pointer-types
-Werror=designated-init -fmacro-prefix-map=/usr/src/linux-heade
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.c:21:1: warning:
missing terminating " character
 "
 ^
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.c:21:1: error:
missing terminating " character
make[4]: ***
[/usr/src/linux-headers-4.19.0-21-common/scripts/Makefile.build:315:
/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s/hello-1.o] Error 1
make[3]: *** [/usr/src/linux-headers-4.19.0-21-common/Makefile:1561:
_module_/home/martind/tmp/make-kernel-MAKEFLAGS-with-an-s] Error 2
make[2]: *** [Makefile:146: sub-make] Error 2
make[1]: *** [Makefile:8: all] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-4.19.0-21-amd64'
make: *** [Makefile:8: modules] Error 2
martind@pizzagate:~/tmp/make-kernel-MAKEFLAGS-with-an-s$ 


This was accepted as a Linux kernel build system bug rather than a Make bug,
so there's nothing to do here, but I for one will likely have to compile
modules for the afflicted kernels for years yet, so I thought the work around
was worth sharing.  Bug #63347 didn't seem like the ideal place.  I guess the
mailing list archives are sufficiently durable and I could probably have
replied to the old thread without spamming the wrong bug.







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