From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0A0F8B67A; Sat, 12 Oct 2024 05:20:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728710459; cv=none; b=D463EtuqNn144pyONWy+7bILj0/oyVD+y77FAa9i1NOYv84CMnUfZa8x5GC+ZGb9zOBlVa0ahGOfcKETcmd22xLf2bm979ofE+lvkuK7DaoNAjTD090lT5O7W1H5sQAhWGxsMenVeLYfDxEbEuDAe3L0Omi62lMESaLVFM46ORY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728710459; c=relaxed/simple; bh=BzwsNGwWPFbLQrywGqQnb8DA672Q23+r40wwcBCKWv0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=CIFrUn+mnh8eCHqlOdJZ42gf0ZeBnejL4B4qgLJWJ5dKUj/2vcqC+2ZTLcf3F7kC4cp+yAjkaoObrUJyG1/Lk82Z2tafBR+c0JEgdVqyRnYrqeqb9MQ78ALX3QPJMIv/ygW/jqgNcgXizI5sFnBUVMEYZa/gzLqYVEqzbec+/RE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GXZncEE0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GXZncEE0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2906DC4CEC6; Sat, 12 Oct 2024 05:20:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728710458; bh=BzwsNGwWPFbLQrywGqQnb8DA672Q23+r40wwcBCKWv0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=GXZncEE06NownrToKmaAR9eeFS8yLicRU0Wg8sHHa7yPfhVK09vpkxeGShSLAIha3 46beUDZvv7QCbiqJwOjhVbJ28DtL3o5y1ZkIGKl9wlmXeOHVhqnTw6zdKZaVtagX6C KJi/1clzW5f/rERNDpCuSfFfuI5GTlAvBY2M2JwVn4IR3u/7OA7sakyMNYzSen9lfP vkepmNPFiBDgQ9/+IcJRn0M+L5GhfuGUe6iPm8vTeWHaVU9PK/2mJMY04I8X2RPC3N sugaNx8qW4FPWgKPQqR5D6U9pe9Ksicoz3EVYIYY9DqPjhcHwWzXnT4C0ZhDuN82NT gJKLkMzGVHz2A== Date: Sat, 12 Oct 2024 14:20:54 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: LKML , Linux Trace Kernel , Masami Hiramatsu , Mathieu Desnoyers Subject: Re: [PATCH] ring-buffer: Fix refcount setting of boot mapped buffers Message-Id: <20241012142054.bc1fffb7b4829ff2e496e566@kernel.org> In-Reply-To: <20241011165224.33dd2624@gandalf.local.home> References: <20241011165224.33dd2624@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 11 Oct 2024 16:52:24 -0400 Steven Rostedt wrote: > From: Steven Rostedt > > A ring buffer which has its buffered mapped at boot up to fixed memory > should not be freed. Other buffers can be. The ref counting setup was > wrong for both. It made the not mapped buffers ref count have zero, and the > boot mapped buffer a ref count of 1. But an normally allocated buffer > should be 1, where it can be removed. > > Keep the ref count of a normal boot buffer with its setup ref count (do > not decrement it), and increment the fixed memory boot mapped buffer's ref > count. > Looks good to me. Reviewed-by: Masami Hiramatsu (Google) Thank you, > Fixes: e645535a954ad ("tracing: Add option to use memmapped memory for trace boot instance") > Signed-off-by: Steven Rostedt (Google) > --- > kernel/trace/trace.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index c01375adc471..5ba40f39c8b5 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -10610,10 +10610,10 @@ __init static void enable_instances(void) > * cannot be deleted by user space, so keep the reference > * to it. > */ > - if (start) > + if (start) { > tr->flags |= TRACE_ARRAY_FL_BOOT; > - else > - trace_array_put(tr); > + tr->ref++; > + } > > while ((tok = strsep(&curr_str, ","))) { > early_enable_events(tr, tok, true); > -- > 2.45.2 > -- Masami Hiramatsu (Google)