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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c2966159c07sm441454566b.63.2026.09.14.06.35.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2026 06:35:09 -0700 (PDT) From: David Carlier To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, David Carlier Subject: [PATCH v2 1/2] tracing: Take trace_types_lock when dropping the buffer_meta reference Date: Mon, 14 Sep 2026 14:35:04 +0100 Message-ID: <20260914133506.4865-2-devnexen@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260914133506.4865-1-devnexen@gmail.com> References: <20260914133506.4865-1-devnexen@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" tracing_buffer_meta_open() drops the trace_array reference with __trace_array_put() when ring_buffer_meta_seq_init() fails, without holding trace_types_lock. Use trace_array_put() like every other open error path. Fixes: 950032ffcee7 ("ring-buffer: Add output of ring buffer meta page") Signed-off-by: David Carlier --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 8658cad53cb5..c8295324ffaa 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5881,7 +5881,7 @@ static int tracing_buffer_meta_open(struct inode *ino= de, struct file *filp) =20 ret =3D ring_buffer_meta_seq_init(filp, tr->array_buffer.buffer, cpu); if (ret < 0) - __trace_array_put(tr); + trace_array_put(tr); return ret; } =20 --=20 2.55.0 From nobody Fri Sep 25 10:03:18 2026 Received: from mail-ej1-f43.google.com (mail-ej1-f43.google.com [209.85.218.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2222047A88C for ; Mon, 14 Sep 2026 13:35:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789392917; cv=none; b=PkxO4tO3AmnYjL1OHc/D7FF7cguWYdakzP3wQmH7pRK4ChhGXzKqq7L/glDZw1nN4VykGOq6u/bOBXKFeBWM+DFyZNr5mYR2/oVuyNBOUMtYK72AmqCWjoyRiewymSMA153gwi4Yp4yg7EB1icxqgzE5FVI2SHw/ft3vtoF9aYA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789392917; c=relaxed/simple; bh=rob29vuMJiM6unglL8riKgmWKOv8j0OKpd04pbbohkE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=chshS3JfRkzzD7f/Wefg1OU0LhmyN+6S0E4C7rll0UMwfoq4L+xMmZZZmMSeV9j2SPCPzSSEbGVC+nc0QUqhFp9Ihino1SlSe1+2dJAEZn9uIyQdq+YCUl99D65VIBE/ow78KSHj+hPXiEyfugVB6LNAx+WNigKxHN12hihU1So= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=kZAT7/a3; arc=none smtp.client-ip=209.85.218.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kZAT7/a3" Received: by mail-ej1-f43.google.com with SMTP id a640c23a62f3a-c253425b253so514176366b.1 for ; Mon, 14 Sep 2026 06:35:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1789392912; x=1789997712; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=7u5qVr4y53yodZo8gWGizbwm6BRp6jZIIKbBtggqr88=; b=kZAT7/a3mbujJosWxfKTCqT05ZSrRD39fxUF+69ap/lY2cHDGuhz90ofIQJUrYehE0 +Xe90th42rikLASkxM7qCuidIGtuzIf2CR0jy1x5UM5SEq912DiWgw45ml2Cv1AgYkQj yUl9PznwmGvwu7RkgeE5ObJweqps9tZ66u0kj7TCsfs9mjB8Rlj1UFU2FX67+cg+cIFc +ehIitYjJcyFcvDy+tgUPuqZPsBXWOt6/lBKp6vt2yCIQOpAHYBS4QcQrW33xk60f5/l 6DZSHwMqRcMN9jGrHrT3AioIuexDBhok7pbeCcjf5HVbmkGyhTzp7rBhOtjyHMH/aWz9 2Vkg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789392912; x=1789997712; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=7u5qVr4y53yodZo8gWGizbwm6BRp6jZIIKbBtggqr88=; b=Cu1Zc2TzUYmbs2bAaRfe0r8ribrGljp7wSwkr/8ei6rkMDEsYKnPwlLynozGSsRB7V 4wQHytqIsgU2pT0d/Uhv7kDbB5Q0FGktuSWaN8V/R7ifLGwhVZ+1bfPItODoWyYnFBDf NjgJaYwlOcPeiN/CQGnD0DpHQRfNWsHSCzmwnGddVVRNTKkUukVCi3d4eC1mD37BQyw6 H7WuobcgpqcdvFAmwmI0oDh9rnmL/T1pMv38ePty1RNEpbWLm6CB79zENxiYc+wU+RXX r9xooB8oL4dmxYDkEP/AJ1/VY8zasAAEoz0eR6M7prbJC/SQ9NSfER3rpB5u6jqaGUpq tQBw== X-Forwarded-Encrypted: i=1; AKwUvByIfVjZavHGZxu5HyypAIjsq+R9y0NttqTW+gu8F/W7jNTnjCA5xkgbOklELuBbq2YgfZZMbAtA22WHDPw=@vger.kernel.org X-Gm-Message-State: AFuF++lVXVl7uRHr+1xtrLLtQZ5C75+IUBJcqw0R0KWQbbUGwgB/p4MM fkopr141Pc28qU+Pgd1QdpvlPwTAEEvdsgIK9i8eYrUsagVSD7ZlL/mC X-Gm-Gg: AYBFou05JLvi7H8VKGSK57TaxhcLBzU1qjCzUCl4r+4W6yMo7DRrofZlOBzwKZNzsrD Qlqs9d+Qve8K7331J43+CXOkk4u0g12E4w4ELgm4UWaz3CIwN79K9467AZriDebisk/zOfaA2HE hF/RFCeJjt8bOipUn8/A4sKEwAJWmPFvKSNOErbKD5ESyTb7iIgtw1ByYP+bSCtZFour3oafb+x lMFAhH7nL8qKCtQ7pwR0cTse84HLOiUlT/pe/jX8Ovsrhwmw6c5h3v31F8BYi0WF0R4pVBzRf7f ROrL42SkjKiC5kO0pPZI6iLrW7xPfTAbgmjNe3o9bS3dcxwhxxbLP0kO/P2xesTb6Hq/Y778dUS r/fIQOwzvtxJm7/SKHVyQTQW/at8TIVegtis6VMVUTJhT2OFvAUV1dF568Pittvw4/fAe0ojiiN 287RkOoAbKyqaIpX7CVuNDRm63canl9/bLODG1kiRVnICAbhqWSrMmKonRNt+W9dr022BO2BdEj wXFAns5sT6biz4fxzUJR10+0whgsGG59N7AFTmIAQNCC6VMyA92uXX5gm4= X-Received: by 2002:a17:907:1c2a:b0:c26:2fc8:4e91 with SMTP id a640c23a62f3a-c29b87055ffmr157187366b.29.1789392911608; Mon, 14 Sep 2026 06:35:11 -0700 (PDT) Received: from dohko.chello.ie (188-141-5-72.dynamic.upc.ie. [188.141.5.72]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c2966159c07sm441454566b.63.2026.09.14.06.35.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Sep 2026 06:35:11 -0700 (PDT) From: David Carlier To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, David Carlier , stable@vger.kernel.org, Sashiko Subject: [PATCH v2 2/2] ring-buffer: Do not show buffer_meta for CPUs without a buffer Date: Mon, 14 Sep 2026 14:35:05 +0100 Message-ID: <20260914133506.4865-3-devnexen@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260914133506.4865-1-devnexen@gmail.com> References: <20260914133506.4865-1-devnexen@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 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 --- kernel/trace/ring_buffer.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 9c03a555a6ba..8833d04b9fee 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2381,6 +2381,9 @@ int ring_buffer_meta_seq_init(struct file *file, stru= ct trace_buffer *buffer, in struct seq_file *m; int ret; =20 + if (!cpumask_test_cpu(cpu, buffer->cpumask)) + return -ENODEV; + ret =3D seq_open(file, &rb_meta_seq_ops); if (ret) return ret; --=20 2.55.0