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=1792774733; b=deeYA4+dIrtLQq9u7JgMnU+uTvTJcLgfk9wJrZAH0R6AOQCjtpw06dsHNlnwRDgIMUun RG49USDBXZ1f2MNWwilja1kVWgtoCHnE1BlU0cpMJKfilIh3r1NngBJWAbr+30r1Egz8S NW8RlfcQJOZZUc2F9stVljmcaZiB+GbwVhxUkgjXHFSghbNrqDNe18w+AmH00p0jiyNS+ T/WGbQpoKpZdjg9ndudWp0mGduHb7Ohmj4a1X0JwtBARsPspx+l5aRb0Q/APSJ9t0ua8q BhPnCguLw5C1K887IbLI83RXCv34Jv2QD1hRNo2k/BAQ6Z2aux/stPO8jQuw5yXEutQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774733; 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=VRmArm3hiUnpl4dDefsA28ZQla9ifzc0+eEJdnZ3ras=; b=AeAi33QXty+T+nJF/LBMQZM39D3PZMpvY9mgnEclME8IDWIBm+Ce+QZyn8aeaT0haVts zZPTABOYlGAS0sWkp5ej6mcxGNO9vT3UDIjKtfJnIkiERG22Sinx5dweBhG4nReYB18Xw tEuG40NMHqA9nh2YsxUL8BmieKeiQHnPzWqUJzE4Css3jvDfvK+mx/ULs6iJoOslbN3fR BbIc+JSiloXtLemanQ7XyY52ozczEjEKdFOFaGEDAzjON/OKSNaXHiOddsxnvfBnOCCKS S4i1rFWr6S1dcCHikqrh9xIR7IK5x5yPLZpNdNC8o2z3GGEvZI5A10nMR7mrJASeHgg== 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=SjqpO5dB; 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 994CB606A31D; Fri, 23 Oct 2026 16:58:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=SjqpO5dB Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD71E1F01825; Fri, 23 Oct 2026 16:58:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774733; bh=VRmArm3hiUnpl4dDefsA28ZQla9ifzc0+eEJdnZ3ras=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SjqpO5dB50plMvIaOz6UeOPFitjetJXOoDBPAbt1yvvyvEkUkrRG76tst5EsspI6R /RCn8aXfutIVtVgQaf+OFMDMOLkzTvMFLp7p+QyVNnC0Mhm5BI2LY5RmqYxYimKyTc X1+oc+rmk+XwpHL+UPvtczklESO3Hijn3TWXfpVg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , David Carlier , Steven Rostedt Subject: [PATCH 7.2 141/242] ring-buffer: Do not show buffer_meta for CPUs without a buffer Date: Fri, 23 Oct 2026 18:39:43 +0200 Message-ID: <20261023163717.113979488@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163713.816071858@linuxfoundation.org> References: <20261023163713.816071858@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Carlier commit 3f23cae09a4677a3f7c163a68388512cb231ff22 upstream. The per_cpu/cpuN/buffer_meta files are created for every possible CPU, but buffer->buffers[cpu] is only allocated once that CPU comes online. Reading the file of a CPU that never came online dereferences a NULL cpu_buffer in rbm_start(). Fail the open with -ENODEV when the CPU has no buffer, as the other per CPU ring buffer interfaces do. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260914133506.4865-3-devnexen@gmail.com Fixes: 950032ffcee7 ("ring-buffer: Add output of ring buffer meta page") Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260913134906.6E8A01F000FF@smtp.kernel.org/ Signed-off-by: David Carlier Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/ring_buffer.c | 3 +++ 1 file changed, 3 insertions(+) --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2362,6 +2362,9 @@ int ring_buffer_meta_seq_init(struct fil struct seq_file *m; int ret; + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -ENODEV; + ret = seq_open(file, &rb_meta_seq_ops); if (ret) return ret;