From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C725B582B80 for ; Fri, 11 Sep 2026 19:55:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156563; cv=none; b=AvJNa5fo8V0icrfJ6WoC0k7LqN/sKa0xns0HckqB395edbgaQ7R8oIwOb/PrPWFIq6a5GlzRbIeKZU8K7jhlFjVDiHT5R5O9WtPrIvNt5laFB/Cxq+z5EVDgVOHXAneH5oK7lJE18saojPkim2dWDKXu7OzrJx2slIhDtBXW+Wo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156563; c=relaxed/simple; bh=FVMPTQDbBIwsz/V9/J7NcSkXsmW0pvsrqbmv7cFvz6A=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=CfyDwBcp+z8vR2VJVLWVjfcGpgE557jrckR8gEkXlsq6R/2Upq/sUaKOun75YOFgLloWAFe4yYYR3Wugk77kYbFyAMH7bpzM+1FcfxgALKyHlStyzBJFXsBpATTT3E8sWx6d9vfK37ntbjEU7CkDJPSgueiX7CA2sOwzCoeg/So= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=K8i6Q4S2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K8i6Q4S2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BCEBF1F000FF; Fri, 11 Sep 2026 19:55:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156547; bh=J/3E0IY/UZdEWNH+8AnI0aM2DNX049RLE0dwOPOMN4M=; h=From:To:Cc:Subject:Date:Reply-To; b=K8i6Q4S20p6lj9AO+yw7YUkswVJy3HuWZmQD7VGHU5peQnIgvuYP1t/EUFKHUtsYp 45Y5YB6rvHhFt8MVYmg++TOaimRBaNUVrQ1gJv6PzCpj+btWKzpfJA4QheTCcXfqan knxNweXj2zntob2rJ5ZNd9llCKDyXuhZqhguxFro= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89519: sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return Date: Fri, 11 Sep 2026 21:43:28 +0200 Message-ID: <2026091114-CVE-2026-89519-b25f@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2838; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=Ts9PYGeIHAE7boYs6LHj3KhM+1xqGanQ6GQZ1Mv6nIA=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIqN2/eFviNt/+OV33k2/LIuWlDMdZtr3uVt6w7aFh dslcoXudcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBE4uUZZjJGfN1Yl3hM6ZaX e2781PSdbpvt9jMsmPwmosj1rsvzdbKTXfaVvRe0aNFqAQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: sched_ext: Replace SCX_RQ_BAL_KEEP with a dispatch verdict return SCX_RQ_BAL_KEEP tells the pick to keep running the previous task, a leftover from when balancing and picking were separate operations. An rq-level flag only works while dispatches and picks pair up one to one, which core scheduling breaks: selections interleave through dispatch's lock drops and a pick can consume a stale flag, keeping a task that has since been dequeued. Fixing core scheduling support requires the decision to travel with the dispatch that made it. Make scx_dispatch_sched() and balance_one() return an explicit verdict instead and drop the flag's plumbing from the tools autogen enum headers. Also factor the pick-side invocation, its follow-up queueing and the post-dispatch checks out of do_pick_task_scx() into dispatch_pick(). No functional changes intended. v2: Drop the SCX_RQ_BAL_KEEP plumbing from the tools autogen enum headers as well (Andrea). The Linux kernel CVE team has assigned CVE-2026-89519 to this issue. Affected and fixed versions =========================== Issue introduced in 6.19 with commit 4c95380701f58b8112f0b891de8d160e4199e19d and fixed in 7.2.4 with commit 6f1d3bfe54430f8d54e0530a27f2ecbf8466576e Issue introduced in 6.19 with commit 4c95380701f58b8112f0b891de8d160e4199e19d and fixed in 7.3-rc1 with commit ffaab58d217581cb75353168f8812a16e10463fc Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-89519 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: kernel/sched/ext/ext.c kernel/sched/sched.h tools/sched_ext/include/scx/enum_defs.autogen.h tools/sched_ext/include/scx/enums.autogen.bpf.h tools/sched_ext/include/scx/enums.autogen.h Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/6f1d3bfe54430f8d54e0530a27f2ecbf8466576e https://git.kernel.org/stable/c/ffaab58d217581cb75353168f8812a16e10463fc