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 31A315867F5 for ; Fri, 11 Sep 2026 19:58:25 +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=1789156717; cv=none; b=IoiQXqASu2f4cPfSkAniUPyeJ2TrNHxSpXbu6W+ODw9gkQcMmjlxxgPRgB10TwuETgJwgh7E08wZ4xP+lkZRDUxTU4ReNFfyOIv9itRQmxY68nLnSnEChtjZ38lmXPzap1stMCePPib6Kfu34/KNltHp3Gdq+RTJxnvWchnUCTM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156717; c=relaxed/simple; bh=aO7P2P9qw25eBb04/QNU2yoj2nPeZAYOC+Q64mE2aUY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=HP8EaGn+Q8N0pZi9qWs1xVPCzBCE5FRIFIhj4bYTCRtqHOU0aX6aPsHTP5O+TKAYq89LqMVSlTZASGvJriH9ntlw0eYMoJq/dzs8S/+H4Vc+QGEsclxYmE/4CMZfyM7t0NcNDT2zrJGJYzlfQ6mMhFESSzleWaj5Kn+689spZw0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=wDGrmCP4; 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="wDGrmCP4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 282ED1F000FF; Fri, 11 Sep 2026 19:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156705; bh=+t3ZKbM3BPjb6UHh01V2uBZxZLbR55Srrp2q5pGddpk=; h=From:To:Cc:Subject:Date:Reply-To; b=wDGrmCP479zdH+vf2WTXqlFw1B4P8jPV464rkCZZF5Vo9Pj9YLEtXSJT+IBLJD7s3 ZRQdge/qkteDaSqqyuUYX58n0ntMSKNFVbj51cNYGgsnmCN78B9O1z4eAqeLmBbuiP tw2MNmJ0xNWASHOq1XCeyIy12hRdbkNQptwvhydo= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89589: acpi/apei/ghes: Use raw_spinlock_t for CXL CPER work locks Date: Fri, 11 Sep 2026 21:44:38 +0200 Message-ID: <2026091130-CVE-2026-89589-6677@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=3861; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=p8N0uJyRy5seuNko0ZxxHdkGtYCT/hl1JpISAxE4k7s=; b=kA0DAAIRMUfUDdst+ykByyZiAGqkWWqgK8yShIYTm6uo2BaRlmLNjz2PJPqyAo3sB7E6/ZhGp YhdBAARAgAdFiEE9LYMxb94wiFKMT3LMUfUDdst+ykFAmqkWWoACgkQMUfUDdst+ynubACgjZpI QybI803/pcWWyRYEXHTDZlYAnjt6QO2avuD6Eo4M9RkGwZyeF02E 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: acpi/apei/ghes: Use raw_spinlock_t for CXL CPER work locks The CXL CPER work registration and unregistration helpers acquire cxl_cper_work_lock and cxl_cper_prot_err_work_lock with a spinlock guard(), which leaves local interrupts enabled. The corresponding post paths (cxl_cper_post_event(), cxl_cper_post_prot_err()) execute in hard IRQ context (they are called from the GHES error notification path) and acquire the same locks with an irqsave guard(). If a CPU is holding one of these locks via a spinlock guard() when a GHES interrupt arrives on the same CPU, the IRQ handler spins on the held lock waiting for it to release, while the lock holder is preempted by the IRQ. The result is a deadlock. Convert both locks from spinlock_t to raw_spinlock_t and use guard() at all call sites. On PREEMPT_RT kernels spinlock_t is backed by rt_mutex and sleeping from hard IRQ context is not permitted; raw_spinlock_t is safe in both contexts. Add WARN_ONCE to both register functions to surface double-registration bugs at runtime. Restructure both unregister functions to clear the global work pointer under the lock before calling cancel_work_sync(), closing the window where a CPER interrupt could schedule work on a pointer about to be freed. Add kfifo_reset() after cancel_work_sync() so stale entries are not replayed on next module load. Both kfifos are single-consumer: only one work_struct is registered at a time, enforced by the WARN_ONCE guard in the register functions. kfifo_reset() is safe outside the lock because cancel_work_sync() has already quiesced the consumer, and no new consumer can register until the current module exit completes and a fresh module init runs. Remove the redundant cancel_work_sync() call from cxl_ras_exit() and cxl_pci_driver_exit(). The CPER unregister functions now quiesce the work internally. The Linux kernel CVE team has assigned CVE-2026-89589 to this issue. Affected and fixed versions =========================== Issue introduced in 6.10 with commit 5e4a264bf8b55d5a1b4c8cd96ac10b99f98d7487 and fixed in 6.18.50 with commit c735dbce7ad03df708bf22ec964f67e43cbc823a Issue introduced in 6.10 with commit 5e4a264bf8b55d5a1b4c8cd96ac10b99f98d7487 and fixed in 7.2.4 with commit 0e25382b05de48d09b243d3d447d236a6d735bc2 Issue introduced in 6.10 with commit 5e4a264bf8b55d5a1b4c8cd96ac10b99f98d7487 and fixed in 7.3-rc1 with commit 6625ca499c3131ef63be3215f8f942d7a097ea3a 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-2026-89589 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: drivers/acpi/apei/ghes.c drivers/cxl/core/ras.c drivers/cxl/pci.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/c735dbce7ad03df708bf22ec964f67e43cbc823a https://git.kernel.org/stable/c/0e25382b05de48d09b243d3d447d236a6d735bc2 https://git.kernel.org/stable/c/6625ca499c3131ef63be3215f8f942d7a097ea3a