On Fri, Nov 16, 2018 at 03:54:19PM +0800, Qu Wenruo wrote: > From: Su Yanjun <suyj.fnst@xxxxxxxxxxxxxx> > > When using gcc8 compiles utils.c, it complains as below: > > utils.c:852:45: warning: '%s' directive output may be truncated writing > up to 4095 bytes into a region of size 4084 [-Wformat-truncation=] > snprintf(path, sizeof(path), "/dev/mapper/%s", name); > ^~ ~~~~ > In file included from /usr/include/stdio.h:873, > from utils.c:20: > /usr/include/bits/stdio2.h:67:10: note: '__builtin___snprintf_chk' > output between 13 and 4108 bytes into a destination of size 4096 > return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > __bos (__s), __fmt, __va_arg_pack ()); > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > This isn't a type of warning we care about, particularly when PATH_MAX > is much less than either. > > Using the GCC option -Wno-format-truncation to disable this for default > build. > > Signed-off-by: Su Yanjun <suyj.fnst@xxxxxxxxxxxxxx> > [Use cc-disable-warning to fix the not working CFLAGS setting in configure.ac] > Signed-off-by: Qu Wenruo <wqu@xxxxxxxx> > --- > Makefile | 1 + > Makefile.extrawarn | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/Makefile b/Makefile > index f4ab14ea74c8..252299f8869f 100644 > --- a/Makefile > +++ b/Makefile > @@ -49,6 +49,7 @@ CSCOPE_CMD := cscope -u -b -c -q > include Makefile.extrawarn > > EXTRA_CFLAGS := > +EXTRA_CFLAGS += $(call cc-disable-warning, format-truncation) Please don't touch EXTRA_CFLAGS, this is for users who want to override any defaults that are set by build. This should go to CFLAGS. > EXTRA_LDFLAGS := > > DEBUG_CFLAGS_DEFAULT = -O0 -U_FORTIFY_SOURCE -ggdb3 > diff --git a/Makefile.extrawarn b/Makefile.extrawarn > index 5849036fd166..bbb2d5173846 100644 > --- a/Makefile.extrawarn > +++ b/Makefile.extrawarn > @@ -53,6 +53,7 @@ warning-1 += -Wold-style-definition > warning-1 += $(call cc-option, -Wmissing-include-dirs) > warning-1 += $(call cc-option, -Wunused-but-set-variable) > warning-1 += $(call cc-disable-warning, missing-field-initializers) > +warning-1 += $(call cc-disable-warning, format-truncation) It's ok to disable for W=1 but eg. the W=3 level could take all previously disabled warnings. > > warning-2 := -Waggregate-return > warning-2 += -Wcast-align > -- > 2.19.1
