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REPLY(-4.00)[]; BAYES_HAM(-3.00)[99.99%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; RCPT_COUNT_TWO(0.00)[2]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; MISSING_XM_UA(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.cz:email] X-Virus-Scanned: clamav-milter 1.0.3 at in-4.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH] syscalls/mallinfo02: introduce LTP_VAR_USED to avoid optimization X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" Hi! > gcc 15 is a bit more clever and noticed that 'buf' isn't used > for anything so it optimized it out, including call to malloc. > So, there's also no mmap() call behind it and test fails, > because nothing was allocated. Huh, that sounds like the optimizations are getting more and more evil over the time. > Introduce LTP_VAR_USED macro, that makes compiler aware of the > variable and doesn't optimize it out. > > Signed-off-by: Jan Stancek > --- > include/tst_common.h | 2 ++ > testcases/kernel/syscalls/mallinfo2/mallinfo2_01.c | 2 +- > 2 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/include/tst_common.h b/include/tst_common.h > index b14bbae04077..3de826acd0ec 100644 > --- a/include/tst_common.h > +++ b/include/tst_common.h > @@ -13,6 +13,8 @@ > #define LTP_ATTRIBUTE_UNUSED __attribute__((unused)) > #define LTP_ATTRIBUTE_UNUSED_RESULT __attribute__((warn_unused_result)) > > +#define LTP_VAR_USED(p) asm volatile("" :: "m"(p)); p Shouldn't __attribute__((used)) suffice? > #ifndef ARRAY_SIZE > # define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])) > #endif > diff --git a/testcases/kernel/syscalls/mallinfo2/mallinfo2_01.c b/testcases/kernel/syscalls/mallinfo2/mallinfo2_01.c > index 90cf4fcb3b89..51783fc22b80 100644 > --- a/testcases/kernel/syscalls/mallinfo2/mallinfo2_01.c > +++ b/testcases/kernel/syscalls/mallinfo2/mallinfo2_01.c > @@ -26,7 +26,7 @@ void test_mallinfo2(void) > char *buf; > size_t size = 2UL * 1024UL * 1024UL * 1024UL; > > - buf = malloc(size); > + LTP_VAR_USED(buf) = malloc(size); > > if (!buf) > tst_brk(TCONF, "Current system can not malloc 2G space, skip it"); > -- > 2.43.0 > > > -- > Mailing list info: https://lists.linux.it/listinfo/ltp -- Cyril Hrubis chrubis@suse.cz -- Mailing list info: https://lists.linux.it/listinfo/ltp