{"id":2232369,"url":"http://patchwork.ozlabs.org/api/patches/2232369/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260504-qom-tests-v2-45-ef7e3dc94f7a@redhat.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/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":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260504-qom-tests-v2-45-ef7e3dc94f7a@redhat.com>","list_archive_url":null,"date":"2026-05-04T11:35:33","name":"[v2,45/46] 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/people/66774/?format=json","name":"Marc-André Lureau","email":"marcandre.lureau@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260504-qom-tests-v2-45-ef7e3dc94f7a@redhat.com/mbox/","series":[{"id":502649,"url":"http://patchwork.ozlabs.org/api/series/502649/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=502649","date":"2026-05-04T11:34:48","name":"Fix various QOM object life-cycle issues","version":2,"mbox":"http://patchwork.ozlabs.org/series/502649/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2232369/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2232369/checks/","tags":{},"related":[],"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=QXK/VMs3;\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=tLDFCKiyZ3IHoxFsadnpmt3a+eVCWPPwxdz50j2s6oQ=;\n b=owEBbQKS/ZANAwAKAdro4Ql1lpzlAcsmYgBp+IRuzEwHy/3uM3LhfvD1h1GLoHgnQh+T9RSov\n wVKj8uq/8uJAjMEAAEKAB0WIQSHqb2TP4fGBtJ29i3a6OEJdZac5QUCafiEbgAKCRDa6OEJdZac\n 5fbKD/4o51Pq9FXe5oLI4wtU1/Ymo3XZd/+0e1d8KTK2M055ke++G5391NeFtV/Xy648iKRZjNV\n o0mL0c3F3TRlZOM7EON4dzylMpnwe3e4MW15Ft0QmluYpApHDFSSfFc6A4RSKN0IrkwnM2c4Oc1\n L/4GAIxQYu4EZpbrw5GVheLQppS3Dtwk8ne0DdAEQSC21WuDOZWzwjeN5Jjy0WG8WNhToV3Jpu1\n B78P8jualYUQRf3FlD3Gsjdn2AxxTR46x155ExQjhVwEcS6KqQQbzHmHmcu55e5lGvt3C1t0pLG\n 3xUzAUYaZUn+NF+C8x/TKXXKol4XaCWtj6jJobwAvYu5KFYhEB7U8oXMSKOxsW5COob3BkpCANt\n sAOcanAyy4RNcpunC998zo8F6mFbm3Jlo/oLYJW00eCXaSjqFsOcEZ2MV3yWBG8wR0EOurdGA3B\n aYNR3O3szQXJX4IJjkTCC8jIQDgDBSasGluwz7Q3w4y1z7rhdFBSPThEn1wF38mqRzmcKKOrI1s\n pSSL1dMTdCuoFzrPo1CipyuPnAlJzJRVugxKLfpT/4Jj1+gb2vl7eMLUcsvVa8jJoEdoDUh8P6C\n TACksSE3N/CPmSK9+gaqDa1gn7xt+SKYb8qf+7N6Fh2L9oaM9ki70nmY8hNXS49UsVMXKMtmlC+\n GMb/wkxQXXM0/Vg==","X-Developer-Key":"i=marcandre.lureau@redhat.com; a=openpgp;\n fpr=87A9BD933F87C606D276F62DDAE8E10975969CE5","X-Scanned-By":"MIMEDefang 3.4.1 on 10.30.177.111","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":"8","X-Spam_score":"0.8","X-Spam_bar":"/","X-Spam_report":"(0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.444,\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 RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001,\n SPF_PASS=-0.001 autolearn=no 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":["v2","45/46"]}