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=1794064918; b=lUocbVAT6RCk2hMIDZMoM4dQoDXIdhN1p/khrX2/qt7vDow1u6uc69zMhiUUdJ31QGkP w5I94QOwL+j6u1/lN9xdK5ULHnnhUa/sZtJpVq2XCm/GDXM2AlRkD1IqKRaDU0ydZvTaZ sMcJW82VDxQ6ZUzO7M4p26SnNjrc9jYBWTsAfr6xDzS6WDbEFABgv5toQGf2MF1mnac2d 6m+G7C6ZrqfViBPuFU10jNPCyLcgCy169H6bfHq9Sl+z/H1P3/vG3Z6Hu+V5oounpG1ps EiZtxoj3OiSPaB6pr3sLSM6r2SyEMx9YRsaWu6E9ydYXQv/2Fgf/Om+mo0LfE3XY/gg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794064918; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=9WUGMSN4eurK0FXC5F2UXsh/PQemfTRfI1MmmhK4yLM=; b=k93x/AW278izq/Z5Tj1G+hOdAzu/RU4BkFrkMyXcHdjv0WIMvFo1Kdv9nL4vP3piHxGj 9A4h7m71+iU52VxQToHAmhhlBOi7NESu5UCiH+2qnssk06v0+MFVJnJI1VDxOWYtChOVW pywzaEujrO7h4nM1zaz2u6k+mFAhN6BPvknZjqlJea9xEOhY6KmHw5QPlCC+peQQZQbrX O/7wBOT3ucFANpsp4p3HyRmor//YhVUrWqBqjCm9mV2yWoKqD0Avsc8ICzXN2QgrjhXEK mKJcRNX+7ixZeqh0AFCK6TPOe290lrLAjxl++QSwMic0abUDg+tYbet0wpbJDVdYmdA== 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=S5mAXaOp; 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 0BBA0606A33E; Sat, 7 Nov 2026 15:21:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=S5mAXaOp Received: by smtp.kernel.org (Postfix) with ESMTPSA id 929DC1F0089F; Sat, 7 Nov 2026 15:21:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794064917; bh=9WUGMSN4eurK0FXC5F2UXsh/PQemfTRfI1MmmhK4yLM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=S5mAXaOpsmG59IPB74eQF8B/N6zkE0IOIUk3E0iLWLVok0Lg83vovm4cCZjmellj/ HO4Sfgjjm2izxWNoYr6hKZTl3N0PE+XECtPjwlIx1cDM6t6n2g/tzfOLI6grWMQiXo nZughOhPgx9siuZ/YWacqYmr2/A6dv5toQ0ElEQk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Carlier , Vincent Donnefort , Steven Rostedt , Sasha Levin Subject: [PATCH 7.3 0816/1257] ring-buffer: Take cpus_read_lock() when changing the subbuf order Date: Sat, 7 Nov 2026 08:51:52 -0500 Message-ID: <20261107135001.882491202@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Carlier [ Upstream commit 453d0f47b174cac387af48d303c503b84f82212e ] A CPU coming online for the first time gets its per CPU buffer allocated by trace_rb_cpu_prepare(), which then adds it to buffer->cpumask. If that happens while ring_buffer_subbuf_order_set() is running, the CPU shows up after the allocation loop and the install loop walks it with an empty new_pages list, corrupting the buffer. Take cpus_read_lock() as ring_buffer_resize() does. Cc: stable@vger.kernel.org Fixes: f9b94daa542a ("ring-buffer: Set new size of the ring buffer sub page") Link: https://patch.msgid.link/20260916192628.274136-1-devnexen@gmail.com Signed-off-by: David Carlier Reviewed-by: Vincent Donnefort Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 9c4e40847e430..1a1219b6d0fc0 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7466,6 +7466,8 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) if (psize > RB_WRITE_MASK + 1) return -EINVAL; + guard(cpus_read_lock)(); + /* prevent another thread from changing buffer sizes */ guard(mutex)(&buffer->mutex); -- 2.53.0