From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793187470; b=i75PuXE1eVlSl9w+w7Yc03XbXz9fvnQAr1hkDxhNpwimyhPAD6GrgxAka9icqXUJF2LS TjcDYXXqPw8PdCZsI6jLg/Picawq0jF1bIFCg58hlPreG2OJOnGNziM/PE6gga2dIpJvt JZWrEfg9w7rE55O8rCjfwINSnAxxVyO0o7H9MokYySckWtg21P5cL5mxQrgHUmZ9rTaQt UQIWz3ZZBleM8/F43OUUoNkrbkG69Qjx56SqQfUsA3X1NlIw/RBlCXBGXHH5BcrE1IOnP L8daPeNN/gwUmYAt+jBxO36tapv6u5GVRcyDoKu+NLWsa5QL0yXqrN3gZmMOFIY58EA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793187470; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: Reply-To:MIME-Version:Lines:X-Developer-Signature:X-Developer-Key: Content-Transfer-Encoding; bh=vw4tmoW8T68E6xXfDtVF0c5JeLpOqsvmVxfDq1yMa0Y=; b=HvdGT2P9O60NeQdDYozYg9tFz2yHOHISDPI//Q5/cU+H+wpbKkcmy5oHdJ//3crj/klo x8hv6X5MLFD8rKPtGg5dQeFQUKTEH8HaZ/eXNJuBVr8tG9KEyJd5yksGN5knIIPS27Y0s XK2ymvjf6XWn6caPb5rnRhuAlPd/uWaauzvYJtg3wYzdWUB4qGDQn9HfAMnym2G73AZdG tDVMP/pMMkURsBsekAXVPE/Q9nTCHM20Fq2oWIdZ67TJr3dXLsSEAmpNY0PfBaHEOPhNz dBvI2XKMGJPxZUZwCQANl6AUoj1oHQPvFkfNOUZVn9toyEqDK45IX1kpLi946yFuMGQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=uiCRChQO; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3CD7B606A31C for ; Wed, 28 Oct 2026 11:37:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=uiCRChQO Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A4251F01829; Wed, 28 Oct 2026 11:37:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793187469; bh=vw4tmoW8T68E6xXfDtVF0c5JeLpOqsvmVxfDq1yMa0Y=; h=From:To:Cc:Subject:Date:Reply-To; b=uiCRChQOlFt15L9mwhwYNRTaHefAEcjyUCHdpf3HEjspy06mV2cOcuhn30sjpQyN0 7BkbxDzaWWKADMRL6U6T63nwUPW0c9xctY//S6OsxJCtxXa/eeNvdkHVVzKc/nU9Hb BM/GUxI4+B2jsLEHapowYfPvZhR7vlP8WHokT+/s= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-99104: sched_ext: Fix the bypass dispatch claim for schedulers bypassed by an ancestor Date: Wed, 28 Oct 2026 11:34:51 +0100 Message-ID: <2026102852-CVE-2026-99104-2dda@gregkh> X-Mailer: git-send-email 2.56.0 Reply-To: , X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2897; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=YwslKfOP9tcTB32KuYSoOVpbOlneUwnvM/vRIZXB9d8=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkPz5/V7d+8uGtBXfOMgPrzcea3PBWDDVn4Hx34NzXRf rHCtIP/OmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiMycxzJWZXiGxk70l5bFG RbmiTU+gwFJvZ4YF+1SSZQoFEtoytzNPKWapNP5wIv4FAA== 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: Fix the bypass dispatch claim for schedulers bypassed by an ancestor scx_bypass() claims bypass dispatch when the scheduler's depth goes from zero to one and releases it when the depth returns to zero, but propagates only the depth to the descendants, not the claim. A descendant that starts bypassing with its ancestor never claims, and one whose own bypass ends under the ancestor's keeps its claim, as its depth does not return to zero. A sub-scheduler enable whose bypass ends under a PM suspend thus leaks its claim: the parent keeps hosting bypass dispatch and the sub-scheduler's next bypass trips the WARN_ON_ONCE() on the claim. A sub-scheduler disable that starts under a PM suspend has no claim, so once the resume lifts the root's bypass its tasks sit on the parent's bypass DSQs with nobody consuming them. Claim for every descendant whose depth goes from zero to one in the propagation and release every scheduler in the subtree whose depth returned to zero once the tasks have moved out of the bypass DSQs. A parent that is bypassing itself when a descendant claims consumes only its own bypass DSQs, empty until it leaves bypass and becomes the host. The Linux kernel CVE team has assigned CVE-2026-99104 to this issue. Affected and fixed versions =========================== Issue introduced in 7.1 with commit aa2a0a19686c90106ade6a7e848ffbb62d55d733 and fixed in 7.2.13 with commit f0f18075e45d47bef7ff2eb9512ee4f0c7e5f9c7 Issue introduced in 7.1 with commit aa2a0a19686c90106ade6a7e848ffbb62d55d733 and fixed in 7.3 with commit 5bdeca322a6f8d10acaf67cccab1f69747ee7be3 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-2026-99104 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 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/f0f18075e45d47bef7ff2eb9512ee4f0c7e5f9c7 https://git.kernel.org/stable/c/5bdeca322a6f8d10acaf67cccab1f69747ee7be3