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 EE0D1552958 for ; Fri, 11 Sep 2026 19:55:40 +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=1789156546; cv=none; b=QdH+dCxhL+lQaofH7rpj3t/R9bNGwx6KtQdyIr/O+hE8TfUBOI0Ks47/wHEgmaSn6C7KQa1BfuXbXuhnEvZ9MhmcuRtMvEh7UUQGZpAYA7ZdKr2DDuwvmPAeleBZDtSEz/ZtzXf20e8UkWJNk6duQX81+ClzfGVxPGeYF93dxsQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156546; c=relaxed/simple; bh=eEL0VqueD+E/K6VEY56/5KfJnfp3UtM4kaDY1VZZ1+8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=d1oJ1WKFX7xAmGU21/bhfbZsH385HQ7mR15LzyVu2qspXGV+66laDLVafFf14RDjoHxk2FlzelKnufC/iLtZWw1flO4gMCgfXfrnqffeFTEUeZd7c2RarISWySYPxSmqiCLIN2RgNMCfll4yO7liVVyQvcbj/r+IJ+5EVJq7fyo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=puunrpYj; 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="puunrpYj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D468B1F000FF; Fri, 11 Sep 2026 19:55:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156538; bh=S00H4JNDK0wj/kt5g/FxkNCP3XEkO/g2BzkeofnHLEc=; h=From:To:Cc:Subject:Date:Reply-To; b=puunrpYjKs2B1Tby7brNfsXh2HLIHbXbAcmubFsfDr6kgdpbHC6qhklRR597A+KgR z8S7QLBCvjcrodcUdcXF9zn0xhY+aBbQBNTQ3A49+WJ+vMRlHybIWcxaZju9y8linW O6IIyq62pObTgd0HPjejG5lbPTLf3t5N1YedNbbA= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89549: sunrpc: route to a populated pool in svc_pool_for_cpu() Date: Fri, 11 Sep 2026 21:43:58 +0200 Message-ID: <2026091121-CVE-2026-89549-a44c@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=3251; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=H1B/FAxnjFJg1JwNu2uHg+RT2GimH8eAEyal22EuQFQ=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIhPj5/63qThps6XCVbpc9cmHws+7lybmrxHSNFRO9 m46ff1/RywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAExEaTfDPKuHHgePMtm8qXhj LVVq//r5pAvKIQzz01/GSNzr33mQ2evnGdVT3c82974wAgA= 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: sunrpc: route to a populated pool in svc_pool_for_cpu() svc_set_num_threads() spreads the requested threads evenly across the service's pools (base = nrservs / sv_nrpools). When a service runs fewer threads than it has pools -- e.g. an nfsd configured with fewer threads than the host has NUMA nodes while running in "pernode" or "percpu" mode -- the trailing pools are left with no threads at all. svc_xprt_enqueue() selects a pool from the CPU servicing the transport, queues the transport on that pool's sp_xprts, and only wakes a thread from the same pool. Each thread services exclusively its own pool, so a transport that lands on a threadless pool is enqueued on sp_xprts and never picked up: the connection hangs indefinitely. Have svc_pool_for_cpu() skip pools that currently have no threads, falling back to the next populated pool. This trades NUMA locality for a guarantee that the work is actually serviced. sp_nrthreads is only updated under the service mutex; the lockless read here is a best-effort routing hint, so annotate it with data_race(). The Linux kernel CVE team has assigned CVE-2026-89549 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.19 with commit bfd241600a3b0db4fe43c859f1460d0a958d924a and fixed in 6.12.109 with commit 011479cf9a7657d4a3e7cc42a784ac63df594170 Issue introduced in 2.6.19 with commit bfd241600a3b0db4fe43c859f1460d0a958d924a and fixed in 6.18.50 with commit 9d04d64ad192439835ed9884d767353061c3ed6f Issue introduced in 2.6.19 with commit bfd241600a3b0db4fe43c859f1460d0a958d924a and fixed in 7.2.4 with commit 8f766d2d0b4dabf54f8b35812df2b4f481d13316 Issue introduced in 2.6.19 with commit bfd241600a3b0db4fe43c859f1460d0a958d924a and fixed in 7.3-rc1 with commit f6310491c4cdb88af73aa551ec9df1f10a90c709 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-2026-89549 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: net/sunrpc/svc.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/011479cf9a7657d4a3e7cc42a784ac63df594170 https://git.kernel.org/stable/c/9d04d64ad192439835ed9884d767353061c3ed6f https://git.kernel.org/stable/c/8f766d2d0b4dabf54f8b35812df2b4f481d13316 https://git.kernel.org/stable/c/f6310491c4cdb88af73aa551ec9df1f10a90c709