From: Steven Rostedt <rostedt@goodmis.org>
To: 王贇 <yun.wang@linux.alibaba.com>
Cc: Guo Ren <guoren@kernel.org>, Ingo Molnar <mingo@redhat.com>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Helge Deller <deller@gmx.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>,
Joe Lawrence <joe.lawrence@redhat.com>,
Colin Ian King <colin.king@canonical.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Nicholas Piggin <npiggin@gmail.com>,
Jisheng Zhang <jszhang@kernel.org>,
linux-csky@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, live-patching@vger.kernel.org
Subject: Re: [PATCH 1/2] ftrace: disable preemption on the testing of recursion
Date: Tue, 12 Oct 2021 08:17:28 -0400 [thread overview]
Message-ID: <20211012081728.5d357d6c@gandalf.local.home> (raw)
In-Reply-To: <a8756482-024c-c858-b3d1-1ffa9a5eb3f7@linux.alibaba.com>
On Tue, 12 Oct 2021 13:40:08 +0800
王贇 <yun.wang@linux.alibaba.com> wrote:
> @@ -52,11 +52,6 @@ static void notrace klp_ftrace_handler(unsigned long ip,
> bit = ftrace_test_recursion_trylock(ip, parent_ip);
> if (WARN_ON_ONCE(bit < 0))
> return;
> - /*
> - * A variant of synchronize_rcu() is used to allow patching functions
> - * where RCU is not watching, see klp_synchronize_transition().
> - */
I have to take a deeper look at this patch set, but do not remove this
comment, as it explains the protection here, that is not obvious with the
changes you made.
-- Steve
> - preempt_disable_notrace();
>
> func = list_first_or_null_rcu(&ops->func_stack, struct klp_func,
> stack_node);
next prev parent reply other threads:[~2021-10-12 12:17 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-12 5:39 [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing 王贇
2021-10-12 5:40 ` [PATCH 1/2] ftrace: disable preemption on the testing of recursion 王贇
2021-10-12 12:17 ` Steven Rostedt [this message]
2021-10-13 1:46 ` 王贇
2021-10-12 12:24 ` Miroslav Benes
2021-10-12 12:29 ` Steven Rostedt
2021-10-13 1:52 ` 王贇
2021-10-13 1:50 ` 王贇
2021-10-13 2:27 ` Steven Rostedt
2021-10-13 2:36 ` 王贇
2021-10-12 12:43 ` Steven Rostedt
2021-10-13 2:04 ` 王贇
2021-10-13 2:30 ` Steven Rostedt
2021-10-13 2:38 ` 王贇
2021-10-12 5:40 ` [PATCH 2/2] ftrace: prevent preemption in perf_ftrace_function_call() 王贇
2021-10-12 11:20 ` Peter Zijlstra
2021-10-13 1:45 ` 王贇
2021-10-12 5:41 ` [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing 王贇
2021-10-13 3:16 ` [PATCH v2 0/2] fix & prevent the missing preemption disabling 王贇
2021-10-13 3:17 ` [PATCH v2 1/2] ftrace: disable preemption between ftrace_test_recursion_trylock/unlock() 王贇
2021-10-13 3:18 ` [PATCH v2 2/2] ftrace: do CPU checking after preemption disabled 王贇
2021-10-13 3:26 ` [PATCH v2 0/2] fix & prevent the missing preemption disabling Steven Rostedt
2021-10-13 3:33 ` 王贇
2021-10-26 23:48 ` [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing Palmer Dabbelt
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