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Tue, 23 Sep 2025 10:28:23 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1v16oQ-0000000AyOX-3yTq; Tue, 23 Sep 2025 14:28:22 -0300 Date: Tue, 23 Sep 2025 14:28:22 -0300 From: Jason Gunthorpe To: Alessandro Zanni Cc: kevin.tian@intel.com, shuah@kernel.org, iommu@lists.linux.dev, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/iommu: prevent use of uninitialized variable Message-ID: <20250923172822.GD2547959@ziepe.ca> References: <20250923150108.34309-1-alessandro.zanni87@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20250923150108.34309-1-alessandro.zanni87@gmail.com> On Tue, Sep 23, 2025 at 05:01:06PM +0200, Alessandro Zanni wrote: > Fix to avoid the usage of the `res` variable uninitialized in the > following macro expansions. > > It solves the following warning: > In function ‘iommufd_viommu_vdevice_alloc’, > inlined from ‘wrapper_iommufd_viommu_vdevice_alloc’ at > iommufd.c:2889:1: > ../kselftest_harness.h:760:12: warning: ‘ret’ may be used uninitialized > [-Wmaybe-uninitialized] > 760 | if (!(__exp _t __seen)) { \ > | ^ > ../kselftest_harness.h:513:9: note: in expansion of macro ‘__EXPECT’ > 513 | __EXPECT(expected, #expected, seen, #seen, ==, 1) > | ^~~~~~~~ > iommufd_utils.h:1057:9: note: in expansion of macro ‘ASSERT_EQ’ > 1057 | ASSERT_EQ(0, _test_cmd_trigger_vevents(self->fd, dev_id, > nvevents)) > | ^~~~~~~~~ > iommufd.c:2924:17: note: in expansion of macro > ‘test_cmd_trigger_vevents’ > 2924 | test_cmd_trigger_vevents(dev_id, 3); > | ^~~~~~~~~~~~~~~~~~~~~~~~ > > The issue can be reproduced, building the tests, with the command: > make -C tools/testing/selftests TARGETS=iommu > > Signed-off-by: Alessandro Zanni > --- > tools/testing/selftests/iommu/iommufd_utils.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) I think it should be like this? @@ -1042,15 +1042,12 @@ static int _test_cmd_trigger_vevents(int fd, __u32 dev_id, __u32 nvevents) .dev_id = dev_id, }, }; - int ret; - while (nvevents--) { - ret = ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT), - &trigger_vevent_cmd); - if (ret < 0) + while (nvevents--) + if (ioctl(fd, _IOMMU_TEST_CMD(IOMMU_TEST_OP_TRIGGER_VEVENT), + &trigger_vevent_cmd)) return -1; - } - return ret; + return 0; } And add a fixes line? Jason