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([2405:201:682f:389d:fc92:597c:e074:9e0e]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-8231877005dsm4839572b3a.68.2026.01.24.05.22.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 24 Jan 2026 05:22:30 -0800 (PST) From: Deepanshu Kartikey To: jgg@ziepe.ca, kevin.tian@intel.com, joro@8bytes.org, will@kernel.org, robin.murphy@arm.com Cc: iommu@lists.linux.dev, Deepanshu Kartikey , syzbot+df28076a30d726933015@syzkaller.appspotmail.com Subject: [PATCH] iommufd: Initialize batch->kind in batch_clear() Date: Sat, 24 Jan 2026 18:52:14 +0530 Message-ID: <20260124132214.624041-1-kartikey406@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit KMSAN reported an uninitialized value when batch_add_pfn_num() reads batch->kind. This occurs because batch_clear() does not initialize the kind field, leaving it with garbage data when a struct pfn_batch is declared on the stack. When batch_add_pfn_num() checks "if (batch->kind != kind)", it reads this uninitialized value, triggering KMSAN warnings. Initialize batch->kind to zero in batch_clear() to ensure the field always starts in a known state. Reported-by: syzbot+df28076a30d726933015@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=df28076a30d726933015 Fixes: f394576eb11db ("iommufd: PFN handling for iopt_pages") Tested-by: syzbot+df28076a30d726933015@syzkaller.appspotmail.com Signed-off-by: Deepanshu Kartikey --- drivers/iommu/iommufd/pages.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c index dbe51ecb9a20..f606148920fa 100644 --- a/drivers/iommu/iommufd/pages.c +++ b/drivers/iommu/iommufd/pages.c @@ -289,6 +289,7 @@ static void batch_clear(struct pfn_batch *batch) batch->end = 0; batch->pfns[0] = 0; batch->npfns[0] = 0; + batch->kind = 0; } /* -- 2.43.0