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Wed, 9 Sep 2026 13:49:39 +0000 (GMT) Date: Wed, 9 Sep 2026 19:19:36 +0530 From: Gautam Menghani To: Chaithanya Lagisetty Cc: pbonzini@redhat.com, seanjc@google.com, shuah@kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests: kvm: Fix transposed calloc() arguments in the uffd helper Message-ID: References: <20260904052033.3648259-1-nagachaithanya9911@gmail.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260904052033.3648259-1-nagachaithanya9911@gmail.com> X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: 9eICNbdAGc1dM7c0EPq-6akPTP0aYTzK X-Proofpoint-GUID: zlMKD7G2Lt4LzMLjtdKJ-Eu_gCZ78Clh X-Authority-Analysis: v=2.4 cv=DbEnbPtW c=1 sm=1 tr=0 ts=6aa163f9 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=kj9zAlcOel0A:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=pGLkceISAAAA:8 a=VnNF1IyMAAAA:8 a=q2RsVZR9PaoYCt8hnh0A:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTA5MDE1MSBTYWx0ZWRfX7+ZjmaZWHxxl sYhBwAvghoPW2UT3D7sTHr1bU4FETF/tTOZVsO3z0E7cCN5XxxR6nshOyhyCXOxgn5Yk96oTgj0 mRdaKrkXFwjdshA9HvO2AZG1zIqu3cFiVhMVedBZiKaHuFridWG+se3nT6TEA2kEjNBPtZuN5Ei C8yWJV8XZHN0Z5V0IM8pPErmzclGW0NQhHapcXuFmpCfu3Dv2AW/xhK8uV2Csk+ck2Jqg/6kApw tkH0KDtM/arTtKEXBCNoIgDRk6ssTwj2ZJ+7e810jJ9DAILo1PdY4LZ04oc2F58HvG+85fxb4ak LssloLCGqLYElSfRYr9vATM/EHp9rXsCEHu7M25afw6s+DY634PwsErCo5DrJxLN1kX/TF1z7Ua 38ph3rIVheBvpnRXIgOZK915piOQTrIFR6Mgy1LzLFEiU5pAtLT3V2or5uW3EyKa7BkOXV1A15i Pm7hVSQaQTwk8mL0o5A== X-Proofpoint-Spam-Info: AW1haW4tMjYwOTA5MDE1MSBTYWx0ZWRfXwzzDhPtnVcrX DixBrJw+n2P0TIjTjmyglJK+Phev2BUcFGeuhZ5D73xBHeeWgJZEd15YKsCiqzqNpp69hrGOJEO VnYXfmTt3INbV3nUfiMID5Ffue0wOH0= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-08_03,2026-09-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 impostorscore=0 adultscore=0 spamscore=0 clxscore=1011 suspectscore=0 bulkscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609090151 On Fri, Sep 04, 2026 at 05:20:33AM +0000, Chaithanya Lagisetty wrote: > uffd_setup_demand_paging() passes the element size as the first argument > to calloc() and the element count as the second: > > uffd_desc->pipefds = calloc(sizeof(int), num_readers); > > calloc() expects the number of elements first and the size of each element > second. The product, and therefore the allocation size, is the same either > way, so this is not a functional change, but the arguments are misleading > and GCC 14 diagnoses them with -Wcalloc-transposed-args, which is enabled > by -Wextra. > > Swap the arguments to match the calloc() prototype. > > Signed-off-by: Chaithanya Lagisetty > --- > tools/testing/selftests/kvm/lib/userfaultfd_util.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/kvm/lib/userfaultfd_util.c b/tools/testing/selftests/kvm/lib/userfaultfd_util.c > index f7ce5a6ddcc2..49eff05b7d39 100644 > --- a/tools/testing/selftests/kvm/lib/userfaultfd_util.c > +++ b/tools/testing/selftests/kvm/lib/userfaultfd_util.c > @@ -119,13 +119,13 @@ struct uffd_desc *uffd_setup_demand_paging(int uffd_mode, useconds_t delay, > uffd_desc = malloc(sizeof(struct uffd_desc)); > TEST_ASSERT(uffd_desc, "Failed to malloc uffd descriptor"); > > - uffd_desc->pipefds = calloc(sizeof(int), num_readers); > + uffd_desc->pipefds = calloc(num_readers, sizeof(int)); > TEST_ASSERT(uffd_desc->pipefds, "Failed to alloc pipes"); > > - uffd_desc->readers = calloc(sizeof(pthread_t), num_readers); > + uffd_desc->readers = calloc(num_readers, sizeof(pthread_t)); > TEST_ASSERT(uffd_desc->readers, "Failed to alloc reader threads"); > > - uffd_desc->reader_args = calloc(sizeof(struct uffd_reader_args), num_readers); > + uffd_desc->reader_args = calloc(num_readers, sizeof(struct uffd_reader_args)); > TEST_ASSERT(uffd_desc->reader_args, "Failed to alloc reader_args"); > > uffd_desc->num_readers = num_readers; > -- > 2.43.0 > Good catch Reviewed-by: Gautam Menghani