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 93D9E1CCB21; Thu, 27 Mar 2025 21:38:52 +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=1743111533; cv=none; b=bx2atcJtG4n+Ajkb7+akTG57Hk6s3z1JF2vKjF60lEovS0nSu7jjjMlpB/docPOfgZIaTDqidjftsAIot1ycUxZgx9BKCGn4utvGKlrDfwMe34gj6oy1+tCFEL3NvMc0zl/2aOl+I7gQIto1pjgKuhACRxcRs3Kt9jBuR5i2CvU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743111533; c=relaxed/simple; bh=KwwlIvn4CGJviwfKhK4vVhwZ4cEFfDMs09ARBlHVKB0=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=NkLqlY6I/86M1GMHmny5mThjmjS/XzGIZChWZu7IEV9TOblis4u0vNhdC3jEJotfFxp6u0TOpAXeUmHzHpC8EFHFT9b/jg9NxWn+L0qH1xllImRzmquzOnhbd5y1Z+er0UECDkjJLwsCnpqdcpNky+nVMV6nhlspyNVHFOC79Lk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J0k6he5v; 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="J0k6he5v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C397C4CEDD; Thu, 27 Mar 2025 21:38:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743111532; bh=KwwlIvn4CGJviwfKhK4vVhwZ4cEFfDMs09ARBlHVKB0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=J0k6he5vHB0B8ms50bsKPAIQ3nWtJPjZg9pRVh3d7TFMXwlbdgiVid95WGo1FQ9ZX qtFEIWbqB55KyYwJcpRlL4h6vLa02BU0GC6ZJnP3RhZd29ybN1B7IChGs37+2Bc4L1 0HbNjtUMXVSWnTVEmRR593gJQOnDb1ZprTSlGF5u7Z+Jyb055yVUhXyZs+zV3x7oSr dLsJ9uT+m3u1NYi7CE1y63OhtBcnUyJ7I82WpAlyC9uViMddPS8hbNdqgTVJfbKyQm oyW1jlyKk6g2FHEPWuokO2kyQ5mLn1QrH0KyYFmp4k2EtDMJgwESBHe2dTGIISfwWk CPSd08kMj4jKw== Date: Fri, 28 Mar 2025 06:38:48 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: LKML , Linux Trace Kernel , Masami Hiramatsu , Mathieu Desnoyers Subject: Re: [PATCH] tracing: Use _text and the kernel offset in last_boot_info Message-Id: <20250328063848.8d4a71fbb8e2a969c46bb27d@kernel.org> In-Reply-To: <20250326220304.38dbedcd@gandalf.local.home> References: <20250326220304.38dbedcd@gandalf.local.home> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-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 Wed, 26 Mar 2025 22:03:04 -0400 Steven Rostedt wrote: > From: Steven Rostedt > > Instead of using kaslr_offset() just record the location of "_text". This > makes it possible for user space to use either the System.map or > /proc/kallsyms as what to map all addresses to functions with. > Looks good to me. Reviewed-by: Masami Hiramatsu (Google) Thank you, > Signed-off-by: Steven Rostedt (Google) > --- > kernel/trace/trace.c | 18 ++++++------------ > 1 file changed, 6 insertions(+), 12 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index 85128ef96246..3b8f5e3313e0 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -51,7 +51,7 @@ > #include > #include > > -#include /* COMMAND_LINE_SIZE and kaslr_offset() */ > +#include /* COMMAND_LINE_SIZE */ > > #include "trace.h" > #include "trace_output.h" > @@ -5995,7 +5995,7 @@ struct trace_mod_entry { > }; > > struct trace_scratch { > - unsigned long kaslr_addr; > + unsigned long text_addr; > unsigned long nr_entries; > struct trace_mod_entry entries[]; > }; > @@ -6137,11 +6137,7 @@ static void update_last_data(struct trace_array *tr) > kfree_rcu(module_delta, rcu); > > /* Set the persistent ring buffer meta data to this address */ > -#ifdef CONFIG_RANDOMIZE_BASE > - tscratch->kaslr_addr = kaslr_offset(); > -#else > - tscratch->kaslr_addr = 0; > -#endif > + tscratch->text_addr = (unsigned long)_text; > } > > /** > @@ -7000,7 +6996,7 @@ static void show_last_boot_header(struct seq_file *m, struct trace_array *tr) > * should not be the same as the current boot. > */ > if (tscratch && (tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) > - seq_printf(m, "%lx\t[kernel]\n", tscratch->kaslr_addr); > + seq_printf(m, "%lx\t[kernel]\n", tscratch->text_addr); > else > seq_puts(m, "# Current\n"); > } > @@ -9465,10 +9461,8 @@ static void setup_trace_scratch(struct trace_array *tr, > tr->scratch = tscratch; > tr->scratch_size = size; > > -#ifdef CONFIG_RANDOMIZE_BASE > - if (tscratch->kaslr_addr) > - tr->text_delta = kaslr_offset() - tscratch->kaslr_addr; > -#endif > + if (tscratch->text_addr) > + tr->text_delta = (unsigned long)_text - tscratch->text_addr; > > if (struct_size(tscratch, entries, tscratch->nr_entries) > size) > goto reset; > -- > 2.47.2 > -- Masami Hiramatsu (Google)