From: Sasha Levin <sashal@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: gregkh@linuxfoundation.org, joel@joelfernandes.org,
paulmck@kernel.org, stable@vger.kernel.org
Subject: Re: FAILED: patch "[PATCH] ftrace: Protect ftrace_graph_hash with ftrace_sync" failed to apply to 5.5-stable tree
Date: Fri, 7 Feb 2020 10:07:28 -0500 [thread overview]
Message-ID: <20200207150728.GW31482@sasha-vm> (raw)
In-Reply-To: <20200207082842.1ce4bf32@oasis.local.home>
On Fri, Feb 07, 2020 at 08:28:42AM -0500, Steven Rostedt wrote:
>
>Hi Greg,
>
>On Fri, 07 Feb 2020 11:16:16 +0100
><gregkh@linuxfoundation.org> wrote:
>
>> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
>> index 8c52f5de9384..3c75d29bd861 100644
>> --- a/kernel/trace/trace.h
>> +++ b/kernel/trace/trace.h
>> @@ -979,6 +979,7 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
>> * Have to open code "rcu_dereference_sched()" because the
>> * function graph tracer can be called when RCU is not
>> * "watching".
>> + * Protected with schedule_on_each_cpu(ftrace_sync)
>> */
>> hash = rcu_dereference_protected(ftrace_graph_hash, !preemptible());
>>
>> @@ -1031,6 +1032,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
>> * Have to open code "rcu_dereference_sched()" because the
>> * function graph tracer can be called when RCU is not
>> * "watching".
>> + * Protected with schedule_on_each_cpu(ftrace_sync)
>> */
>> notrace_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
>> !preemptible());
>
>Ah, I updated that patch to insert these comments, which makes it
>dependent on 16052dd5bdfa ("ftrace: Add comment to why
>rcu_dereference_sched() is open coded"). This is just adding comments
>and should have a very lower risk of breaking anything. If you add that
>patch first, then this patch should apply cleanly. Would it be OK to
>add that comment patch? It should fix most the conflicts.
I've ended up taking these additional commits, and queued everything for
5.5-4.14:
16052dd5bdfa ("ftrace: Add comment to why rcu_dereference_sched() is open coded")
24a9729f8314 ("tracing: Annotate ftrace_graph_hash pointer with __rcu")
fd0e6852c407 ("tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu")
--
Thanks,
Sasha
next prev parent reply other threads:[~2020-02-07 15:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 10:16 FAILED: patch "[PATCH] ftrace: Protect ftrace_graph_hash with ftrace_sync" failed to apply to 5.5-stable tree gregkh
2020-02-07 13:28 ` Steven Rostedt
2020-02-07 15:07 ` Sasha Levin [this message]
2020-02-07 16:53 ` Steven Rostedt
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