| Message ID | 20250106095906.330877-1-ruansy.fnst@fujitsu.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | include/builddefs.in: ignore unused-result warning | expand |
ping~ 在 2025/1/6 17:59, Shiyang Ruan 写道: > When build xfstests, a lot of "unused result" warning are reported: > > [CC] write_log.lo > write_log.c: In function 'wlog_record_write': > write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > 205 | write(wfile->w_afd, wbuf, reclen); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > 209 | write(wfile->w_rfd, wbuf, reclen); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > [CC] random.lo > > Mostly are calused by not using the return value of read()/write()/... > Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This > won't cause other problem but make the log clean. > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > --- > include/builddefs.in | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/builddefs.in b/include/builddefs.in > index 7274cde8d..edf87ff00 100644 > --- a/include/builddefs.in > +++ b/include/builddefs.in > @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ > NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ > HAVE_FICLONE = @have_ficlone@ > > -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall > +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result > > ifeq ($(PKG_PLATFORM),linux) > PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS)
On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: > When build xfstests, a lot of "unused result" warning are reported: > > [CC] write_log.lo > write_log.c: In function 'wlog_record_write': > write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > 205 | write(wfile->w_afd, wbuf, reclen); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > 209 | write(wfile->w_rfd, wbuf, reclen); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > [CC] random.lo Hi, I never hit this build warning: # make ... Building lib [LTDEP] [CC] write_log.lo [LD] Building ltp [CC] doio [CC] fsstress ... Besides that ... > > Mostly are calused by not using the return value of read()/write()/... > Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This > won't cause other problem but make the log clean. > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > --- > include/builddefs.in | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/builddefs.in b/include/builddefs.in > index 7274cde8d..edf87ff00 100644 > --- a/include/builddefs.in > +++ b/include/builddefs.in > @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ > NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ > HAVE_FICLONE = @have_ficlone@ > > -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall > +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result I'm not an expert of gcc. From the manual of gcc, it says: -Wno-unused-result Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. Looks like the "-Wno-unused-result" works for "a function marked with attribute warn_unused_result", e.g. int __attribute__((warn_unused_result)) foo(void) I think fstests doesn't use that attribute. Thanks, Zorro > > ifeq ($(PKG_PLATFORM),linux) > PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) > -- > 2.43.0 > >
On Wed, Jan 15, 2025 at 11:33:27PM +0800, Zorro Lang wrote: > On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: > > When build xfstests, a lot of "unused result" warning are reported: > > > > [CC] write_log.lo > > write_log.c: In function 'wlog_record_write': > > write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > 205 | write(wfile->w_afd, wbuf, reclen); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > 209 | write(wfile->w_rfd, wbuf, reclen); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > [CC] random.lo > > Hi, > > I never hit this build warning: > > # make > ... > Building lib > [LTDEP] > [CC] write_log.lo > [LD] > Building ltp > [CC] doio > [CC] fsstress > ... > > Besides that ... > > > > > Mostly are calused by not using the return value of read()/write()/... > > Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This > > won't cause other problem but make the log clean. > > > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > > --- > > include/builddefs.in | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/include/builddefs.in b/include/builddefs.in > > index 7274cde8d..edf87ff00 100644 > > --- a/include/builddefs.in > > +++ b/include/builddefs.in > > @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ > > NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ > > HAVE_FICLONE = @have_ficlone@ > > > > -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall > > +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result > > I'm not an expert of gcc. From the manual of gcc, it says: > > -Wno-unused-result > Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. > > Looks like the "-Wno-unused-result" works for "a function marked with > attribute warn_unused_result", e.g. > > int __attribute__((warn_unused_result)) foo(void) > > I think fstests doesn't use that attribute. No, but unistd.h does for write(): extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur __attr_access ((__read_only__, 2, 3)); where "__wur" is a macro wrapping __attribute__ ((__warn_unused_result__)) if available and FORTIFY_SOURCE is nonzero. But, uh, shouldn't we fix these programs either to fail the test because some part of its execution failed, or declare that the return value is irrelevant if that's the case? --D > Thanks, > Zorro > > > > > > ifeq ($(PKG_PLATFORM),linux) > > PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) > > -- > > 2.43.0 > > > > > >
在 2025/1/15 23:33, Zorro Lang 写道: > On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: >> When build xfstests, a lot of "unused result" warning are reported: >> >> [CC] write_log.lo >> write_log.c: In function 'wlog_record_write': >> write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] >> 205 | write(wfile->w_afd, wbuf, reclen); >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] >> 209 | write(wfile->w_rfd, wbuf, reclen); >> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >> [CC] random.lo > > Hi, > > I never hit this build warning: > > # make > ... > Building lib > [LTDEP] > [CC] write_log.lo > [LD] > Building ltp > [CC] doio > [CC] fsstress > ... > > Besides that ... Could you share me the info of your build environment? Such as OS, kernel, gcc version. I'd like to find out what wrong with mine. -- Thanks, Ruan. > >> >> Mostly are calused by not using the return value of read()/write()/... >> Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This >> won't cause other problem but make the log clean. >> >> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> >> --- >> include/builddefs.in | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/include/builddefs.in b/include/builddefs.in >> index 7274cde8d..edf87ff00 100644 >> --- a/include/builddefs.in >> +++ b/include/builddefs.in >> @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ >> NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ >> HAVE_FICLONE = @have_ficlone@ >> >> -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall >> +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result > > I'm not an expert of gcc. From the manual of gcc, it says: > > -Wno-unused-result > Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. > > Looks like the "-Wno-unused-result" works for "a function marked with > attribute warn_unused_result", e.g. > > int __attribute__((warn_unused_result)) foo(void) > > I think fstests doesn't use that attribute. > > Thanks, > Zorro > > >> >> ifeq ($(PKG_PLATFORM),linux) >> PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) >> -- >> 2.43.0 >> >> >
On Thu, Jan 16, 2025 at 05:55:49PM +0800, Shiyang Ruan wrote: > > > 在 2025/1/15 23:33, Zorro Lang 写道: > > On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: > > > When build xfstests, a lot of "unused result" warning are reported: > > > > > > [CC] write_log.lo > > > write_log.c: In function 'wlog_record_write': > > > write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > > 205 | write(wfile->w_afd, wbuf, reclen); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > > 209 | write(wfile->w_rfd, wbuf, reclen); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > [CC] random.lo > > > > Hi, > > > > I never hit this build warning: > > > > # make > > ... > > Building lib > > [LTDEP] > > [CC] write_log.lo > > [LD] > > Building ltp > > [CC] doio > > [CC] fsstress > > ... > > > > Besides that ... > > Could you share me the info of your build environment? Such as OS, kernel, > gcc version. I'd like to find out what wrong with mine. Do you use gcc-15? > > > -- > Thanks, > Ruan. > > > > > > > > > Mostly are calused by not using the return value of read()/write()/... > > > Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This > > > won't cause other problem but make the log clean. > > > > > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > > > --- > > > include/builddefs.in | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/include/builddefs.in b/include/builddefs.in > > > index 7274cde8d..edf87ff00 100644 > > > --- a/include/builddefs.in > > > +++ b/include/builddefs.in > > > @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ > > > NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ > > > HAVE_FICLONE = @have_ficlone@ > > > -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall > > > +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result > > > > I'm not an expert of gcc. From the manual of gcc, it says: > > > > -Wno-unused-result > > Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. > > > > Looks like the "-Wno-unused-result" works for "a function marked with > > attribute warn_unused_result", e.g. > > > > int __attribute__((warn_unused_result)) foo(void) > > > > I think fstests doesn't use that attribute. > > > > Thanks, > > Zorro > > > > > > > ifeq ($(PKG_PLATFORM),linux) > > > PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) > > > -- > > > 2.43.0 > > > > > > > > >
On Wed, Jan 15, 2025 at 01:45:47PM -0800, Darrick J. Wong wrote: > On Wed, Jan 15, 2025 at 11:33:27PM +0800, Zorro Lang wrote: > > On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: > > > When build xfstests, a lot of "unused result" warning are reported: > > > > > > [CC] write_log.lo > > > write_log.c: In function 'wlog_record_write': > > > write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > > 205 | write(wfile->w_afd, wbuf, reclen); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] > > > 209 | write(wfile->w_rfd, wbuf, reclen); > > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > [CC] random.lo > > > > Hi, > > > > I never hit this build warning: > > > > # make > > ... > > Building lib > > [LTDEP] > > [CC] write_log.lo > > [LD] > > Building ltp > > [CC] doio > > [CC] fsstress > > ... > > > > Besides that ... > > > > > > > > Mostly are calused by not using the return value of read()/write()/... > > > Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This > > > won't cause other problem but make the log clean. > > > > > > Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> > > > --- > > > include/builddefs.in | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/include/builddefs.in b/include/builddefs.in > > > index 7274cde8d..edf87ff00 100644 > > > --- a/include/builddefs.in > > > +++ b/include/builddefs.in > > > @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ > > > NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ > > > HAVE_FICLONE = @have_ficlone@ > > > > > > -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall > > > +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result > > > > I'm not an expert of gcc. From the manual of gcc, it says: > > > > -Wno-unused-result > > Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. > > > > Looks like the "-Wno-unused-result" works for "a function marked with > > attribute warn_unused_result", e.g. > > > > int __attribute__((warn_unused_result)) foo(void) > > > > I think fstests doesn't use that attribute. > > No, but unistd.h does for write(): > > extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur > __attr_access ((__read_only__, 2, 3)); > > where "__wur" is a macro wrapping __attribute__ > ((__warn_unused_result__)) if available and FORTIFY_SOURCE is nonzero. Oh, good to know that :) > > But, uh, shouldn't we fix these programs either to fail the test because > some part of its execution failed, or declare that the return value is > irrelevant if that's the case? The warning is not a big deal, /but/ I just found GCC-15 changed lots of default things, especially use -std=gnu23 by default: https://gcc.gnu.org/gcc-15/porting_to.html that causes xfstests can't be built with gcc-15 ... lots of build errors. It can be "fixed"(skipped) by set -std=gnu17: -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall +GCCFLAGS = -funsigned-char -fno-strict-aliasing -std=gnu17 -Wall but I'm not sure if it's a good way. I'm wondering should we port to C23 totally... It needs to changes lots of "old style" C codes. Thanks, Zorro > > --D > > > Thanks, > > Zorro > > > > > > > > > > ifeq ($(PKG_PLATFORM),linux) > > > PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) > > > -- > > > 2.43.0 > > > > > > > > > > >
在 2025/1/17 12:01, Zorro Lang 写道: > On Thu, Jan 16, 2025 at 05:55:49PM +0800, Shiyang Ruan wrote: >> >> >> 在 2025/1/15 23:33, Zorro Lang 写道: >>> On Mon, Jan 06, 2025 at 05:59:06PM +0800, Shiyang Ruan wrote: >>>> When build xfstests, a lot of "unused result" warning are reported: >>>> >>>> [CC] write_log.lo >>>> write_log.c: In function 'wlog_record_write': >>>> write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] >>>> 205 | write(wfile->w_afd, wbuf, reclen); >>>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] >>>> 209 | write(wfile->w_rfd, wbuf, reclen); >>>> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>>> [CC] random.lo >>> >>> Hi, >>> >>> I never hit this build warning: >>> >>> # make >>> ... >>> Building lib >>> [LTDEP] >>> [CC] write_log.lo >>> [LD] >>> Building ltp >>> [CC] doio >>> [CC] fsstress >>> ... >>> >>> Besides that ... >> >> Could you share me the info of your build environment? Such as OS, kernel, >> gcc version. I'd like to find out what wrong with mine. > > Do you use gcc-15? I'm using gcc v13, installed from Ubuntu 24.04's apt. $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/13/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa OFFLOAD_TARGET_DEFAULT=1 Target: x86_64-linux-gnu Configured with: ... Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 13.3.0 (Ubuntu 13.3.0-6ubuntu2~24.04) -- Thanks, Ruan. > >> >> >> -- >> Thanks, >> Ruan. >> >>> >>>> >>>> Mostly are calused by not using the return value of read()/write()/... >>>> Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This >>>> won't cause other problem but make the log clean. >>>> >>>> Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> >>>> --- >>>> include/builddefs.in | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/include/builddefs.in b/include/builddefs.in >>>> index 7274cde8d..edf87ff00 100644 >>>> --- a/include/builddefs.in >>>> +++ b/include/builddefs.in >>>> @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ >>>> NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ >>>> HAVE_FICLONE = @have_ficlone@ >>>> -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall >>>> +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result >>> >>> I'm not an expert of gcc. From the manual of gcc, it says: >>> >>> -Wno-unused-result >>> Do not warn if a caller of a function marked with attribute "warn_unused_result" does not use its return value. The default is -Wunused-result. >>> >>> Looks like the "-Wno-unused-result" works for "a function marked with >>> attribute warn_unused_result", e.g. >>> >>> int __attribute__((warn_unused_result)) foo(void) >>> >>> I think fstests doesn't use that attribute. >>> >>> Thanks, >>> Zorro >>> >>> >>>> ifeq ($(PKG_PLATFORM),linux) >>>> PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS) >>>> -- >>>> 2.43.0 >>>> >>>> >>> >> >
diff --git a/include/builddefs.in b/include/builddefs.in index 7274cde8d..edf87ff00 100644 --- a/include/builddefs.in +++ b/include/builddefs.in @@ -75,7 +75,7 @@ HAVE_RLIMIT_NOFILE = @have_rlimit_nofile@ NEED_INTERNAL_XFS_IOC_EXCHANGE_RANGE = @need_internal_xfs_ioc_exchange_range@ HAVE_FICLONE = @have_ficlone@ -GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall +GCCFLAGS = -funsigned-char -fno-strict-aliasing -Wall -Wno-unused-result ifeq ($(PKG_PLATFORM),linux) PCFLAGS = -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 $(GCCFLAGS)
When build xfstests, a lot of "unused result" warning are reported: [CC] write_log.lo write_log.c: In function 'wlog_record_write': write_log.c:205:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] 205 | write(wfile->w_afd, wbuf, reclen); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ write_log.c:209:13: warning: ignoring return value of 'write' declared with attribute 'warn_unused_result' [-Wunused-result] 209 | write(wfile->w_rfd, wbuf, reclen); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ [CC] random.lo Mostly are calused by not using the return value of read()/write()/... Ignore this warning by adding `-Wno-unused-result` to CCFLAGS. This won't cause other problem but make the log clean. Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com> --- include/builddefs.in | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)