{"id":2229145,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229145/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427-qom-tests-v1-40-c413f3605311@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260427-qom-tests-v1-40-c413f3605311@redhat.com>","date":"2026-04-27T19:42:39","name":"[40/41] hw/i2c/pmbus: fix undefined behavior in pmbus_direct_mode2data","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"d4dfbeb2766de26513f5d52b74568873b4eb8bf4","submitter":{"id":66774,"url":"http://patchwork.ozlabs.org/api/1.1/people/66774/?format=json","name":"Marc-André Lureau","email":"marcandre.lureau@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260427-qom-tests-v1-40-c413f3605311@redhat.com/mbox/","series":[{"id":501716,"url":"http://patchwork.ozlabs.org/api/1.1/series/501716/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=501716","date":"2026-04-27T19:42:03","name":"Fix various QOM object life-cycle issues","version":1,"mbox":"http://patchwork.ozlabs.org/series/501716/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229145/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229145/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=Ac0jO+er;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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a=openpgp-sha256; l=1137;\n i=marcandre.lureau@redhat.com; h=from:subject:message-id;\n bh=2dC++hVlKU9GL8wkcDvF8pRIuTJVc02X3ZdB8ioXtmc=;\n b=owEBbQKS/ZANAwAKAdro4Ql1lpzlAcsmYgBp77wWCSMLWSFlL5vt4DE7S0EM5qpi04Dpc02qu\n p6FV0ylYJOJAjMEAAEKAB0WIQSHqb2TP4fGBtJ29i3a6OEJdZac5QUCae+8FgAKCRDa6OEJdZac\n 5aqGEACx0uhHWEOvrKH+OM/eJnMfLtK/oZ2FIQ06+ockve3mGc8evJRD6BiAD6iCEwLqKCuxT/J\n A4YMSPcegVtKYcFNcPYGogfeMIQ3KWDKOhuOmXHBCh2EBlEABp60YnPFb93dMCwbD3LsSllmP/2\n WXGMoAOmoHM7LPRulsKa6AFsQYZbrehZcJYt+cXwDpKa0rMJUHGs1VQ8PQBhDsJRCESEfGgPDhi\n dtsO1SX3ILQOQ7fValcvDFkKWxVNnXdKq5EfTKKy+VzT5bAisceOddWJsPcdHT5GIoBQLaz0K6/\n ZbapY7KqiC5yDY4hF84hz9aeeK6Ar8zOOmo+wnkYvr3C1Bs489Unpli9Uk2BJZGeZPvkfTncgM+\n U286pHCRVv+0Ngi91sNuB9Qrf/rvlDAQelxUimNZPj73Vu7qpJpzJK8vAutlLGKwBf8IM4hTEqy\n F0Wdcg6qJUiqtPhYWi5ZS6+PO9QIF5H+7+1iu7EDqs3vukoA7U2VV+7KMCd/x2LeI41H/yu0SK+\n PL10FcYWCS6Kok/b2djb7SMv2X2m1yxakQspVPnc6UaXuFdYDZURwSgGu7nI7rdOBQyb9/GDNnb\n 1iwKqkTWmdd/Bs7GbtwDDEH44myq5pLgWDg7EXrpeI9koKc3ANE2cQlt96CWUHthMLvnLr15kMi\n n630XJ939sJxjXA==","X-Developer-Key":"i=marcandre.lureau@redhat.com; a=openpgp;\n fpr=87A9BD933F87C606D276F62DDAE8E10975969CE5","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.4","Received-SPF":"pass client-ip=170.10.133.124;\n envelope-from=marcandre.lureau@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com","X-Spam_score_int":"-20","X-Spam_score":"-2.1","X-Spam_bar":"--","X-Spam_report":"(-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001,\n SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"The intermediate result of (Y * 10^-R - b) / m can be negative when\nthe bias (b) is large and the raw register value is small (e.g. zero\non an uninitialized device). Assigning that negative double to uint32_t\nis undefined behavior, caught by UBSan/clang.\n\nUse a double intermediate and clamp negative results to zero.\n\nFixes: 3746d5c15e70 (\"hw/i2c: add support for PMBus\")\nSigned-off-by: Marc-André Lureau \n---\n hw/i2c/pmbus_device.c | 4 ++--\n 1 file changed, 2 insertions(+), 2 deletions(-)","diff":"diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c\nindex 853dc4b4342..861f5b4fb63 100644\n--- a/hw/i2c/pmbus_device.c\n+++ b/hw/i2c/pmbus_device.c\n@@ -23,8 +23,8 @@ uint16_t pmbus_data2direct_mode(PMBusCoefficients c, uint32_t value)\n uint32_t pmbus_direct_mode2data(PMBusCoefficients c, uint16_t value)\n {\n /* X = (Y * 10^-R - b) / m */\n- uint32_t x = (value / pow(10, c.R) - c.b) / c.m;\n- return x;\n+ double x = (value / pow(10, c.R) - c.b) / c.m;\n+ return (x > 0) ? (uint32_t)x : 0;\n }\n \n uint16_t pmbus_data2linear_mode(uint16_t value, int exp)\n","prefixes":["40/41"]}