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=1793207622; b=Zd7kRsiND6rWpaWXaLaTYybH/PLr6Zz0dou3NN5X6KoLbINYGacOcnjsnHh+4gGYuQq0 mW+URVPhpnB6+Ig84bR32ktGA5WmA8m7xKMEzw5Alfjf/EPB68J+DN/Ic/GseU7UIa9t9 O3BU7Y/eXwFSoeO5Cr368LSU8vRopIHyViNOIAIuefIuaW1SF07ESjD3XWN7AXfJ8xjUp 3ZaqGiSUffWk3PXt1TSqGKEJWzfXhfQN5orwFmHgSGggRyuFh8V4WtV1/kKvH6ro4VGh3 rpkFMZ2/pY/o+JlQq90chcV4neGpLmCo+BPreQj/g4Vv6eV/M1ROr6MaKmaHYaEzogg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793207622; 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=BGBkTGUwCfxKMz8o0GYyyNruBa9FklqEOAr9fYxdwZ4=; b=tsgiXgmvXTDB9Fl242N++7tDxRShpKXkFJUlJ72bX7VvYyJLI6OQxKZrxIzOnCqWTH9v sANLIEcorTR6zitCTdN1QhhJJIiJ+enykiJLdu9m/QDvsw06kPaJdQFi2nzxK6d87KRvV Lv2Odmop55i3jh4HvyMVhfhIZ46Y0sOActq0JVKiDvwTVSnhkgQXeTb77YpdKoGZq//vh X8BkYl2k2W7he23RfB/GLdVeCu9yM8hVAcGEwpQG/4rGGBeN400wPNXPEET2sDjAwMUjq Yg78fehkEnFfDb/8fMZBmqo5/86AmEwMf5As0cXWK3pi5VcHx2FQWFnfZDAfdGToCMw== 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=TUxy9mwH; 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 43108606A31A; Wed, 28 Oct 2026 17:13:42 +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=TUxy9mwH Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9367E1F01825; Wed, 28 Oct 2026 17:13:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793207622; bh=BGBkTGUwCfxKMz8o0GYyyNruBa9FklqEOAr9fYxdwZ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TUxy9mwHKzgq2t2qxPI02kV0Kpak/C0wTMfV7i5XhYctzT1yUF6EWIt6To95augsi JD/52RenBOBRYVQZEO04YHyP7TANHZy3id/MdAg7+aaFCnfiiGaChSqWiY47W/fnuB C3hNOGiHkBEMR92T1n8kNsFe5jerXelvXHiTJaqE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sashiko , David Carlier , Steven Rostedt Subject: [PATCH 6.12 079/247] ring-buffer: Do not show buffer_meta for CPUs without a buffer Date: Wed, 28 Oct 2026 17:58:02 +0100 Message-ID: <20261028165949.263786034@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165947.349197979@linuxfoundation.org> References: <20261028165947.349197979@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 6.12-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 @@ -2106,6 +2106,9 @@ 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;