From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] tracing: Make the backup instance readonly
Date: Thu, 8 Jan 2026 12:07:39 +0900 [thread overview]
Message-ID: <20260108120739.e85941b9d7d67f15ded52410@kernel.org> (raw)
In-Reply-To: <20260107114133.7f14dac2@gandalf.local.home>
On Wed, 7 Jan 2026 11:41:33 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> > @@ -4888,6 +4888,9 @@ static int tracing_open(struct inode *inode, struct file *file)
> > int cpu = tracing_get_cpu(inode);
> > struct array_buffer *trace_buf = &tr->array_buffer;
> >
> > + if (trace_array_is_readonly(tr))
> > + return -EPERM;
>
> So this fails if someone opens a file in RDONLY mode?
>
> Why?
This is for `trace` file and this block is to erase the buffer.
-----
/* If this file was open for write, then erase contents */
if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
int cpu = tracing_get_cpu(inode);
struct array_buffer *trace_buf = &tr->array_buffer;
if (trace_array_is_readonly(tr))
return -EPERM;
-----
Thus, if user opens it RDONLY mode to read the buffer, we don't care
because it is readonly (readable).
Thank you,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
next prev parent reply other threads:[~2026-01-08 3:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-07 14:45 [PATCH 0/2] tracing: Remove backup instance after read all Masami Hiramatsu (Google)
2026-01-07 14:45 ` [PATCH 1/2] tracing: Make the backup instance readonly Masami Hiramatsu (Google)
2026-01-07 16:41 ` Steven Rostedt
2026-01-08 2:51 ` Masami Hiramatsu
2026-01-08 3:05 ` Steven Rostedt
2026-01-08 5:30 ` Masami Hiramatsu
2026-01-08 3:07 ` Masami Hiramatsu [this message]
2026-01-07 14:46 ` [PATCH 2/2] tracing: Add autoremove feature to the backup instance Masami Hiramatsu (Google)
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