From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1610346EC7E; Fri, 14 Aug 2026 12:41:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786711288; cv=none; b=S+iAKX6sY+RzJaF+qbxVnu3BBK+DhlDnKeMsrsaUhOiTvH4zFT1TSfpNP6NYpHSzkGtTJ9Xd/luEv1iapzeBNN5+2FMXIJk2L6sIYWluayPgnnf4KuEP+B7yGB3nz66CgAnWriAbB+bDnX0iJAarl8BDxCX/8HAn9gkND+TWXNA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786711288; c=relaxed/simple; bh=JqnHCT32qVO54UOzLmOYNavvaxQn9B1g5DougJpccrw=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=tXi/rn1mB3e70GqI8+EPK2S0qsJG3Oh+1KRpvET3aK61B97Kt3pEflsRQsurm+O/yDg6hQH1mVADK7C3J6rUCrXNX3+x/mdS7nhS493bL7OZyTO3wc8hDmqip5BWqJ4rk8cNbyIm8Kd8WBqvnrh5j0bE/IeGUzj/eFR8WuwmwiE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gDtMtLa5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gDtMtLa5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 731B11F00A3F; Fri, 14 Aug 2026 12:41:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786711283; bh=1IS8mEyq71qXVERuAbIYDjD6JjBWkULc6LCRV5cXw4Y=; h=Date:From:To:Cc:Subject:References; b=gDtMtLa5pRig4GZcsDgWPkic3VNmskhhC/8x/dZrjsY0Rk4zflB3ytMNajNSIBHec RG97dlkK1Cos3GvkWBBlyxtOmSk7AIEHHL04km+TLJQfW7uXz35eMteGVDzHCbs78V AGez5d03bX+bgL0tGNpZi/i2FYLGwmrW2SRc7CkoUekYLkKGTJGy3PNXBh6PPWc4Cu 0KBNBhfN4pgiXXK6fKq3djt3wRhcfev4gaQW50a4gucSyEeCctWyjf2YSTm4BhRjUO 7stLBx+TLFENJToMfT434ZXd70Eq18py9vYS4wZbF8s3xU4UoYdVhLmSvxftnsxnAO GkweoUsfyAd6w== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1wurED-00000003zlK-41gf; Fri, 14 Aug 2026 08:41:41 -0400 Message-ID: <20260814124141.810285258@kernel.org> User-Agent: quilt/0.69 Date: Fri, 14 Aug 2026 08:41:26 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Sashiko , Vincent Donnefort Subject: [for-next][PATCH 3/9] ring-buffer: Hold cpu_buffer::lock when resizing a subbuf References: <20260814124123.133362396@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Vincent Donnefort Because, ring_buffer_subbuf_order_set() can clear cpu_buffer->free_page, hold cpu_buffer->lock to prevent races with ring_buffer_alloc_read_page() and ring_buffer_free_read_page(). Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260813131152.3589632-3-vdonnefort@google.com Fixes: 8e7b58c27b3c ("ring-buffer: Just update the subbuffers when changing their allocation order") Reported-by: Sashiko Signed-off-by: Vincent Donnefort Signed-off-by: Steven Rostedt --- 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 73a3fb76ba4d..0479c404db03 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -7431,8 +7431,10 @@ int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order) cpu_buffer->nr_pages = cpu_buffer->nr_pages_to_update; cpu_buffer->nr_pages_to_update = 0; + arch_spin_lock(&cpu_buffer->lock); old_free_data_page = cpu_buffer->free_page; cpu_buffer->free_page = NULL; + arch_spin_unlock(&cpu_buffer->lock); rb_head_page_activate(cpu_buffer); -- 2.53.0