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GET /api/patches/2218056/?format=api
{ "id": 2218056, "url": "http://patchwork.ozlabs.org/api/patches/2218056/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260331102608.60882-1-kwolf@redhat.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "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": "<20260331102608.60882-1-kwolf@redhat.com>", "list_archive_url": null, "date": "2026-03-31T10:26:08", "name": "block: Fix crash after setting latency historygram with single bin", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "9b3339068efd8c36bd59180e03536e3afd1eb948", "submitter": { "id": 2714, "url": "http://patchwork.ozlabs.org/api/people/2714/?format=api", "name": "Kevin Wolf", "email": "kwolf@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260331102608.60882-1-kwolf@redhat.com/mbox/", "series": [ { "id": 498170, "url": "http://patchwork.ozlabs.org/api/series/498170/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=498170", "date": "2026-03-31T10:26:08", "name": "block: Fix crash after setting latency historygram with single bin", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/498170/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2218056/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2218056/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "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=T0Fz1+qY;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)" ], "Received": [ "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4flPSJ4DNpz1y1q\n\tfor <incoming@patchwork.ozlabs.org>; Tue, 31 Mar 2026 21:27:11 +1100 (AEDT)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1w7WIw-0006YW-OK; Tue, 31 Mar 2026 06:26:38 -0400", "from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1w7WIk-0006Ne-L2\n for qemu-devel@nongnu.org; Tue, 31 Mar 2026 06:26:30 -0400", "from us-smtp-delivery-124.mimecast.com ([170.10.129.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1w7WIi-0003y7-Tu\n for qemu-devel@nongnu.org; Tue, 31 Mar 2026 06:26:26 -0400", "from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-45-kE__8mKrNe-6d7kTvaqrEw-1; Tue,\n 31 Mar 2026 06:26:20 -0400", "from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 62695195607B; Tue, 31 Mar 2026 10:26:19 +0000 (UTC)", "from merkur.redhat.com (unknown [10.44.50.38])\n by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id E4A9E19560AB; Tue, 31 Mar 2026 10:26:17 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1774952783;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding;\n bh=YMX7uqCepZbBy0LM9S6dtaAYYNd8bWTL8dzhvurWY/c=;\n b=T0Fz1+qY0KwTkOdH96H3Bh9g1Ox518+CYcmxDJrs1sgrtOY7w5MAw8CZF6YXIOSdhoa48w\n BBgMYSVRnn+r4g5EhbO7N85CQaxJd5rxH6YGqZcFKalaxJdk9TLC3L62gFiFZYfsSHz100\n p6UKriLFBKjND21MzEMSU0AnKPLoy7E=", "X-MC-Unique": "kE__8mKrNe-6d7kTvaqrEw-1", "X-Mimecast-MFC-AGG-ID": "kE__8mKrNe-6d7kTvaqrEw_1774952779", "From": "Kevin Wolf <kwolf@redhat.com>", "To": "qemu-block@nongnu.org", "Cc": "kwolf@redhat.com,\n\threitz@redhat.com,\n\tqemu-devel@nongnu.org", "Subject": "[PATCH] block: Fix crash after setting latency historygram with\n single bin", "Date": "Tue, 31 Mar 2026 12:26:08 +0200", "Message-ID": "<20260331102608.60882-1-kwolf@redhat.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Scanned-By": "MIMEDefang 3.0 on 10.30.177.12", "Received-SPF": "pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com", "X-Spam_score_int": "27", "X-Spam_score": "2.7", "X-Spam_bar": "++", "X-Spam_report": "(2.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54,\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_SBL_CSS=3.335,\n RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=1, RCVD_IN_VALIDITY_RPBL_BLOCKED=1,\n SPF_HELO_PASS=-0.001, 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 <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "Passing an empty list of boundaries to block-latency-histogram-set sets\nup a state that leads to a NULL pointer dereference when the next\nrequest should be accounted for. This is not a useful configuration, so\njust error out if the user tries to set it.\n\nThe crash can easily be reproduced with the following script:\n\n qmp() {\n cat <<EOF\n {'execute':'qmp_capabilities'}\n {'execute':'block-latency-histogram-set',\n 'arguments': {'id':'ide0','boundaries':[]}}\n {'execute':'cont'}\n EOF\n }\n\n qmp | ./qemu-system-x86_64 -S -qmp stdio \\\n -drive if=none,format=raw,file=null-co:// \\\n -device ide-hd,drive=none0,id=ide0\n\nSigned-off-by: Kevin Wolf <kwolf@redhat.com>\n---\n block/accounting.c | 9 +++++++++\n 1 file changed, 9 insertions(+)", "diff": "diff --git a/block/accounting.c b/block/accounting.c\nindex 5cf51f029b1..f00fe997403 100644\n--- a/block/accounting.c\n+++ b/block/accounting.c\n@@ -185,6 +185,15 @@ int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,\n prev = entry->value;\n }\n \n+ /*\n+ * block_latency_histogram_account() assumes that it can always access\n+ * hist->boundaries[0], so require at least one boundary. A histogram with\n+ * a single bin is useless anyway.\n+ */\n+ if (new_nbins <= 1) {\n+ return -EINVAL;\n+ }\n+\n hist->nbins = new_nbins;\n g_free(hist->boundaries);\n hist->boundaries = g_new(uint64_t, hist->nbins - 1);\n", "prefixes": [] }