From: Linus Torvalds <torvalds@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] tracing: Simplify the max length test when using the filtering temp buffer
Date: Wed, 9 Jun 2021 15:21:52 -0700 [thread overview]
Message-ID: <CAHk-=wj3S_DxdQkXVaQKcUBCyjiYHC3KqPBTMY151rvZzqKVFQ@mail.gmail.com> (raw)
In-Reply-To: <20210609220537.927890401@goodmis.org>
On Wed, Jun 9, 2021 at 3:05 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> val = this_cpu_inc_return(trace_buffered_event_cnt);
> - if ((len < (PAGE_SIZE - sizeof(*entry) - sizeof(entry->array[0]))) && val == 1) {
> + if (val == 1 && unlikely(len < max_len)) {
unlikely? No.
Also, I still think that "len < max_len" should actually be "len <=
max_len". It should be ok to use the whole page, no?
Unless there is some *other* overflow issue, and "len" doesn't contain
a terminating NUL character or something like that.
Linus
next prev parent reply other threads:[~2021-06-09 22:22 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-09 22:04 [PATCH 0/2] tracing: Simplify and document the trace event filtering temp buffer code Steven Rostedt
2021-06-09 22:04 ` [PATCH 1/2] tracing: Simplify the max length test when using the filtering temp buffer Steven Rostedt
2021-06-09 22:21 ` Linus Torvalds [this message]
2021-06-09 22:36 ` Steven Rostedt
2021-06-09 22:04 ` [PATCH 2/2] tracing: Add better comments for the filtering temp buffer use case Steven Rostedt
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