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=1794063435; b=qI0W+VEAN7SLGvcvnomSFxIJWseyVKamstueg/gPIEkHAuUPIlIiwTsipwGMrvfKDgw0 1m2NXcQbr2fUtU6OUNv87Qrc+4lAR8w/DTGbL5FGAXxLvJnjZohVyx1s/gqDpDCjdtW4X aiK1qeO3ZHToaRBWRvW5oY4mwHF0pG7fDk+Euq6eEKC7Twl908JkRXX70ejksqoYzRFwD uUJdmrScPRS/MgV1gDrFKM9aNdMhRspxAUazWNuxLgu/vLE1AqeJt+IGdHktYOiv+NkXG H9JvQHqREqHuIu41vO7kKtveOfhF+Z5hYDx0PR5tYlDEVo1w0RYjkFd/yJYHbd3A2yQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063435; 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=BkMLqvaYqVDV3W44XAJv13qJUOgJxzL2+MYSt1alY/s=; b=MvPz98WS+9oWEbSC49fLNefM/79Ze20WsW6VYqvneoSdJuRb6r/2HvGNQrk/IdPdKdK1 /r+AzF4g/4U8WH1cVTNQpQ1RytDqVs+A+ROZgQTGjFNmtdBhRSlqcVRjolUe+zw2FuFoh sxsHon+QR6e4ojePYeAoWtX6ZoZJoj7sgaEr7Kie85aOaNrmGLsUWPGwYpEuj3AstfUK/ Wn0BZ/j5xbCmsXJzKaE5EwPqPn/vAUoHLYPSH1IfL8jrOv11b9awbbF6WYP/VqZjPgHg4 yT7HCvnRzSsKiTdsx+RaGxyBIfejHNzlfdfGa3IlwoeaCgqAESdEG46NC3vMf3x3dfA== 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=iJOfBirI; 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 4F5BB606D801; Sat, 7 Nov 2026 14:57:15 +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=iJOfBirI Received: by smtp.kernel.org (Postfix) with ESMTPSA id E8F4D1F0089F; Sat, 7 Nov 2026 14:57:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063435; bh=BkMLqvaYqVDV3W44XAJv13qJUOgJxzL2+MYSt1alY/s=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iJOfBirI0LDfa6QKvO47/R6i9yc0sS+JB6gqsQsve082Nu39o4wEvT13n/IQ8gTKu a9mbyRrAGTRf+KZ+WuiKbXlSEhNvQ6oLXH2VTLfFbvDhtraz1NecmyCbGiIk33JNQr iWq0z3klSW8fE6BurLe9fVSubrdi8/gaMS17ewdo= 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 6.18 597/869] ring-buffer: Take cpus_read_lock() when changing the subbuf order Date: Sat, 7 Nov 2026 08:54:39 -0500 Message-ID: <20261107134913.324751926@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@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 6.18-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 f74acc78866d8..dcb762664ce73 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7004,6 +7004,8 @@ 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