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 BED4C584971 for ; Fri, 11 Sep 2026 19:53:05 +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=1789156396; cv=none; b=fg/7dscg0k2hoxICPKoOAGwxUzIZlQShGDIiPMUElzeWvpIwFfzLWEzkJ9BE7cr/Gaxj8kWgI6MLOAtAUVwd94PiuEPq0F/Csrkg3FNome5bBS6mEmbi0lIRVd7COz/PjMtGbLED6U/IGdDrMnRAPf3ZclO1uAx+CQfNt70yQy8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156396; c=relaxed/simple; bh=29moSpCMhs5nbKocxJUbItLMFbKSRRYGX5xlroAeuQ0=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=KgFhr1Bn6PPdp3jbf9wSE9c9YQXjSzYBPT1mWW7Qa8AP9cj0Z5rOfPzGJXAwW9iyV3UHolezp1n8cz3qMrNAZvfuINl/kRKcdgCxR5qf3+tr6kipxu5W3BGTLHxiqrNlbgex6GP1/sHqv6wgwQsIXWW8/TtEeeA7N1hz70XRcyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PsKBUsGe; 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="PsKBUsGe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A754A1F00893; Fri, 11 Sep 2026 19:53:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156384; bh=wGFGnYMngmytY7+vK+y2VNZltjmeCDKPN+ul/4vUUzY=; h=From:To:Cc:Subject:Date:Reply-To; b=PsKBUsGeny67lfaJDXH15ieARqrcTGm9U9pH1R8YPu7Ayl+ANJspQrERzEm6Rxerq 0cuI/zsmRQSl4whb31aA6isNW3xWDne1TEF+rmSO+ti2Ne3FYyqrbbo2xk8eaBCJcq kwosiqqm0oVRPqkZWB5MYJuXdMVcTjfoMxzKofHU= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-89499: ring-buffer: Stop remote reader update when page swap fails Date: Fri, 11 Sep 2026 21:43:08 +0200 Message-ID: <2026091109-CVE-2026-89499-d253@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=2409; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=6gv81yTbOmLuUNEvd858z23tfwWr/TkPa4Bq8kV9BMc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIkP9955Rfcg6nXnvg/ajW86J+v7ccifj4Qbf/jLzB OP+6RPXdcSyMAgyMciKKbJ82cZzdH/FIUUvQ9vTMHNYmUCGMHBxCsBEzkYxzOFd5aW2PKh0dXBv Q3W6pu6S3VUKeQwLWkWvn6i7orf2z1HjYx6PD7702aAnCAA= 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: ring-buffer: Stop remote reader update when page swap fails The remote swap_reader_page callback can return -EBUSY when the writer moves the head before the remote catches it, particularly during an event storm on a small buffer. __rb_get_reader_page_from_remote() currently warns about that failure but continues with the unchanged reader ID and rearranges the local page list as though the swap succeeded. Handle the callback failure as a recoverable error. Report it with pr_warn_ratelimited() and return NULL. Callers already handle a NULL reader page as a failed attempt. This avoids splicing the same page as both the previous and new reader without flooding the log under contention. The Linux kernel CVE team has assigned CVE-2026-89499 to this issue. Affected and fixed versions =========================== Issue introduced in 7.1 with commit 2e67fabd8b77c4f482df9b211bca1b495c6c2c24 and fixed in 7.2.4 with commit a14a97048e48471e283d76879b83d2ae323e0722 Issue introduced in 7.1 with commit 2e67fabd8b77c4f482df9b211bca1b495c6c2c24 and fixed in 7.3-rc1 with commit 5eab74874d11160725c42ab676ba97a797a362eb 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-2026-89499 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/trace/ring_buffer.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/a14a97048e48471e283d76879b83d2ae323e0722 https://git.kernel.org/stable/c/5eab74874d11160725c42ab676ba97a797a362eb