From: Daniel Axtens <dja@axtens.net> To: Andrew Morton <akpm@linux-foundation.org>, kbuild test robot <lkp@intel.com> Cc: kbuild-all@lists.01.org, Johannes Weiner <hannes@cmpxchg.org>, Dmitry Vyukov <dvyukov@google.com>, Linux Memory Management List <linux-mm@kvack.org> Subject: Re: [hnaz-linux-mm:master 169/698] include/linux/string.h:307:9: note: in expansion of macro '__underlying_strncpy' Date: Tue, 02 Jun 2020 13:53:22 +1000 [thread overview] Message-ID: <87tuzuyvgt.fsf@dja-thinkpad.axtens.net> (raw) In-Reply-To: <87wo4qywp4.fsf@dja-thinkpad.axtens.net> Daniel Axtens <dja@axtens.net> writes: > Hi Andrew, > >>> include/linux/string.h:297:30: warning: '__builtin_strncpy' specified bound 8 equals destination size [-Wstringop-truncation] >>> 297 | #define __underlying_strncpy __builtin_strncpy >>> | ^ >>> >> include/linux/string.h:307:9: note: in expansion of macro '__underlying_strncpy' >>> 307 | return __underlying_strncpy(p, q, size); >>> | ^~~~~~~~~~~~~~~~~~~~ >> >> Looks like another false positive. >> >> Daniel, is there a practical way of suppressing these? > > I think we probably want '-Wno-stringop-truncation'. That will stop > warnings where the bound equals the destination size (so there won't be > any null-truncation). But it won't stop the overflow warnings about > full-on overflows (-Wstringop-overflow). Ah, so both stringop-truncate and stringop-overflow are disabled in Makefile: - commit 5a76021c2eff ("gcc-10: disable 'stringop-overflow' warning for now") - commit 217c3e019675 ("disable stringop truncation warnings for now") However, at W=1, stringop-truncate is re-enabled - last touched commit 64a91907c896 ("kbuild: refactor scripts/Makefile.extrawarn"). That would explain why we see this on test builds with W=1 only. I'll bump it to W=2. > I'll send a patch. > > Regards, > Daniel
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Axtens <dja@axtens.net> To: kbuild-all@lists.01.org Subject: Re: [hnaz-linux-mm:master 169/698] include/linux/string.h:307:9: note: in expansion of macro '__underlying_strncpy' Date: Tue, 02 Jun 2020 13:53:22 +1000 [thread overview] Message-ID: <87tuzuyvgt.fsf@dja-thinkpad.axtens.net> (raw) In-Reply-To: <87wo4qywp4.fsf@dja-thinkpad.axtens.net> [-- Attachment #1: Type: text/plain, Size: 1343 bytes --] Daniel Axtens <dja@axtens.net> writes: > Hi Andrew, > >>> include/linux/string.h:297:30: warning: '__builtin_strncpy' specified bound 8 equals destination size [-Wstringop-truncation] >>> 297 | #define __underlying_strncpy __builtin_strncpy >>> | ^ >>> >> include/linux/string.h:307:9: note: in expansion of macro '__underlying_strncpy' >>> 307 | return __underlying_strncpy(p, q, size); >>> | ^~~~~~~~~~~~~~~~~~~~ >> >> Looks like another false positive. >> >> Daniel, is there a practical way of suppressing these? > > I think we probably want '-Wno-stringop-truncation'. That will stop > warnings where the bound equals the destination size (so there won't be > any null-truncation). But it won't stop the overflow warnings about > full-on overflows (-Wstringop-overflow). Ah, so both stringop-truncate and stringop-overflow are disabled in Makefile: - commit 5a76021c2eff ("gcc-10: disable 'stringop-overflow' warning for now") - commit 217c3e019675 ("disable stringop truncation warnings for now") However, at W=1, stringop-truncate is re-enabled - last touched commit 64a91907c896 ("kbuild: refactor scripts/Makefile.extrawarn"). That would explain why we see this on test builds with W=1 only. I'll bump it to W=2. > I'll send a patch. > > Regards, > Daniel
next prev parent reply other threads:[~2020-06-02 3:53 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-30 10:07 [hnaz-linux-mm:master 169/698] include/linux/string.h:307:9: note: in expansion of macro '__underlying_strncpy' kbuild test robot 2020-05-30 10:07 ` kbuild test robot 2020-06-02 1:04 ` Andrew Morton 2020-06-02 1:04 ` Andrew Morton 2020-06-02 3:26 ` Daniel Axtens 2020-06-02 3:26 ` Daniel Axtens 2020-06-02 3:53 ` Daniel Axtens [this message] 2020-06-02 3:53 ` Daniel Axtens 2020-06-02 5:55 ` Daniel Axtens 2020-06-02 5:55 ` Daniel Axtens 2020-06-02 19:16 ` Andrew Morton 2020-06-02 19:16 ` Andrew Morton 2020-06-05 10:35 ` Daniel Axtens 2020-06-05 10:35 ` Daniel Axtens
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