Re: [PATCH v3 1/2] modpost: rework and consolidate logging interface

From: Masahiro Yamada
Date: Mon Mar 09 2020 - 06:21:33 EST

On Mon, Mar 9, 2020 at 6:59 PM Jessica Yu <jeyu@xxxxxxxxxx> wrote:
>
> +++ Masahiro Yamada [09/03/20 09:40 +0900]:
> >Hi Jessica,
> >
> >
> >
> >On Sat, Mar 7, 2020 at 1:02 AM Jessica Yu <jeyu@xxxxxxxxxx> wrote:
> >>
> >> Rework modpost's logging interface by consolidating merror(), warn(), and
> >> fatal() to use a single function, modpost_log(). Introduce different
> >> logging levels (WARN, ERROR, FATAL) as well. The purpose of this cleanup is
> >> to reduce code duplication when deciding whether or not to warn or error
> >> out based on a condition.
> >>
> >> Signed-off-by: Jessica Yu <jeyu@xxxxxxxxxx>
> >> ---
> >> v3:
> >> - remove level variable from modpost_log and just call fprintf in each
> >> case
> >> - remove warn_unless and just call modpost_log() directly
> >> - fix checkpatch error:
> >> ERROR: space required before the open parenthesis '('
> >> #102: FILE: scripts/mod/modpost.c:61:
> >> + switch(loglevel) {
> >>
> >> scripts/mod/modpost.c | 68 ++++++++++++++++++++++-----------------------------
> >> scripts/mod/modpost.h | 14 ++++++++---
> >> 2 files changed, 40 insertions(+), 42 deletions(-)
> >>
> >> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> >> index 7edfdb2f4497..a2329235a6db 100644
> >> --- a/scripts/mod/modpost.c
> >> +++ b/scripts/mod/modpost.c
> >> @@ -51,41 +51,34 @@ enum export {
> >>
> >> #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
> >>
> >> -#define PRINTF __attribute__ ((format (printf, 1, 2)))
> >> +#define PRINTF __attribute__ ((format (printf, 2, 3)))
> >>
> >> -PRINTF void fatal(const char *fmt, ...)
> >> +PRINTF void modpost_log(enum loglevel loglevel, const char *fmt, ...)
> >> {
> >
> >
> >This series looks good to me.
> >
> >I can queue it up to kbuild tree
> >if there is no objection.
> >
> >
> >I just noticed one nit.
> >
> >Now that modpost_log() is the only user of PRINTF,
> >we can delete PRITNF, and directly add the attribute
> >to modpost_log(), like this:
> >
> >
> >void __attribute__((format(printf, 2, 3)))
> >modpost_log(enum loglevel loglevel, const char *fmt, ...)
> >{
> > ...
> >}
> >
> >
> >If you agree, I can modify it when I apply it.
>
> Yes, I agree with this change. Thank you!
>
> One more thing, it's not immediately obvious to me why the first patch
> would cause those kbuild warnings :-/ I'll see if I have any luck
> reproducing them locally..
>


Hmm, this warning option is not so new.


At least, commit 7c0d35a339db6 (4 years ago)
fixed a similar one.



I use GCC 7.4

If I apply your previous version,
I see build log like follows:




$ gcc --version
gcc (Ubuntu 7.4.0-1ubuntu1~18.04.1) 7.4.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

masahiro@pug:~/ref/linux$ make defconfig all
HOSTCC scripts/kconfig/conf.o
HOSTCC scripts/kconfig/confdata.o
HOSTCC scripts/kconfig/expr.o
LEX scripts/kconfig/lexer.lex.c
YACC scripts/kconfig/parser.tab.[ch]
HOSTCC scripts/kconfig/lexer.lex.o
HOSTCC scripts/kconfig/parser.tab.o
HOSTCC scripts/kconfig/preprocess.o
HOSTCC scripts/kconfig/symbol.o
HOSTCC scripts/kconfig/util.o
HOSTLD scripts/kconfig/conf
*** Default configuration is based on 'x86_64_defconfig'
#
# configuration written to .config
#
SYSTBL arch/x86/include/generated/asm/syscalls_32.h
SYSHDR arch/x86/include/generated/asm/unistd_32_ia32.h
SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h
SYSTBL arch/x86/include/generated/asm/syscalls_64.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_32.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_64.h
SYSHDR arch/x86/include/generated/uapi/asm/unistd_x32.h
HOSTCC arch/x86/tools/relocs_32.o
HOSTCC arch/x86/tools/relocs_64.o
HOSTCC arch/x86/tools/relocs_common.o
HOSTLD arch/x86/tools/relocs
HOSTCC scripts/selinux/genheaders/genheaders
HOSTCC scripts/selinux/mdp/mdp
HOSTCC scripts/kallsyms
HOSTCC scripts/sorttable
HOSTCC scripts/asn1_compiler
HOSTCC scripts/extract-cert
WRAP arch/x86/include/generated/uapi/asm/bpf_perf_event.h
WRAP arch/x86/include/generated/uapi/asm/errno.h
WRAP arch/x86/include/generated/uapi/asm/fcntl.h
WRAP arch/x86/include/generated/uapi/asm/ioctl.h
WRAP arch/x86/include/generated/uapi/asm/ioctls.h
WRAP arch/x86/include/generated/uapi/asm/ipcbuf.h
WRAP arch/x86/include/generated/uapi/asm/param.h
WRAP arch/x86/include/generated/uapi/asm/poll.h
WRAP arch/x86/include/generated/uapi/asm/resource.h
WRAP arch/x86/include/generated/uapi/asm/socket.h
WRAP arch/x86/include/generated/uapi/asm/sockios.h
WRAP arch/x86/include/generated/uapi/asm/termbits.h
WRAP arch/x86/include/generated/uapi/asm/termios.h
WRAP arch/x86/include/generated/uapi/asm/types.h
WRAP arch/x86/include/generated/asm/early_ioremap.h
WRAP arch/x86/include/generated/asm/export.h
WRAP arch/x86/include/generated/asm/mcs_spinlock.h
WRAP arch/x86/include/generated/asm/mm-arch-hooks.h
WRAP arch/x86/include/generated/asm/mmiowb.h
WRAP arch/x86/include/generated/asm/dma-contiguous.h
UPD include/config/kernel.release
UPD include/generated/uapi/linux/version.h
UPD include/generated/utsrelease.h
CC scripts/mod/empty.o
HOSTCC scripts/mod/mk_elfconfig
MKELF scripts/mod/elfconfig.h
HOSTCC scripts/mod/modpost.o
scripts/mod/modpost.c: In function âmodpost_logâ:
scripts/mod/modpost.c:75:2: warning: format not a string literal and
no format arguments [-Wformat-security]
fprintf(stderr, level);
^~~~~~~
CC scripts/mod/devicetable-offsets.s
UPD scripts/mod/devicetable-offsets.h
HOSTCC scripts/mod/file2alias.o
HOSTCC scripts/mod/sumversion.o
HOSTLD scripts/mod/modpost
CC kernel/bounds.s
UPD include/generated/bounds.h
UPD include/generated/timeconst.h
CC arch/x86/kernel/asm-offsets.s


--
Best Regards
Masahiro Yamada