From: Steven Rostedt <rostedt@goodmis.org>
To: Changbin Du <changbin.du@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Ingo Molnar <mingo@redhat.com>, Albert Ou <aou@eecs.berkeley.edu>,
Palmer Dabbelt <palmer@dabbelt.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: ftrace: no need to acquire text_mutex when executed in stop_machine
Date: Thu, 10 Mar 2022 09:27:42 -0500 [thread overview]
Message-ID: <20220310092742.4fcc7131@gandalf.local.home> (raw)
In-Reply-To: <20220310045454.672097-1-changbin.du@gmail.com>
On Thu, 10 Mar 2022 12:54:54 +0800
Changbin Du <changbin.du@gmail.com> wrote:
> It's safe to patch text segment in stop_machine. No race is possible here.
> Besides, there is a false positive for the lock assertion in
> patch_insn_write() since the lock is not held by cpu migration thread.
>
> So we actually don't need our ftrace_arch_code_modify_prepare/post(). And
> the lock assertion in patch_insn_write() should be removed to avoid
> producing lots of false positive warnings.
>
> Signed-off-by: Changbin Du <changbin.du@gmail.com>
Ideally, RISC-V should try to get off of the stop_machine approach, and
move to the breakpoint modification.
-- Steve
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next prev parent reply other threads:[~2022-03-10 14:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-10 4:54 [PATCH] riscv: ftrace: no need to acquire text_mutex when executed in stop_machine Changbin Du
2022-03-10 14:27 ` Steven Rostedt [this message]
2022-03-13 8:07 ` Changbin Du
2022-03-22 2:40 ` Palmer Dabbelt
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