From: Sachin Sant <sachinp@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
open list <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
bsingharora@gmail.com, dja@axtens.net, paulus@ozlabs.org,
Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: WARN include/linux/trace_recursion.h:162 (powerpc)
Date: Thu, 2 Feb 2023 19:31:18 +0530 [thread overview]
Message-ID: <FD2608B2-6A0F-4235-9D54-55C067777E79@linux.ibm.com> (raw)
In-Reply-To: <Y9t6yoafrO5YqVgM@hirez.programming.kicks-ass.net>
>> ---[ end trace 0000000000000000 ]---
>> ------------[ cut here ]------------
>> RCU not on for: shared_cede_loop+0xc/0x170
>>
>> The code in question was added by
>> commit d099dbfd330686a8c09cd8944bcc77a56f9e7815
>> cpuidle: tracing: Warn about !rcu_is_watching()
>
> Note that by selecting ARCH_WANTS_NO_INSTR you effectively state to
> abide by its rules.
>
> 41b7a347bf14 ("powerpc: Book3S 64-bit outline-only KASAN support")
>
> AFAICT the power code does not even attempt to do this.
>
> For your idle path you want at least something like the below, but given
> you don't have build time validation of noinstr I can't really tell and
> you'll just have to run chase the stragglers.
>
Thanks for the feedback Peter. With the interim patch submitted by
Michael, I no longer see this warning.
WARNING: multiple messages have this Message-ID (diff)
From: Sachin Sant <sachinp@linux.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: open list <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
dja@axtens.net
Subject: Re: WARN include/linux/trace_recursion.h:162 (powerpc)
Date: Thu, 2 Feb 2023 19:31:18 +0530 [thread overview]
Message-ID: <FD2608B2-6A0F-4235-9D54-55C067777E79@linux.ibm.com> (raw)
In-Reply-To: <Y9t6yoafrO5YqVgM@hirez.programming.kicks-ass.net>
>> ---[ end trace 0000000000000000 ]---
>> ------------[ cut here ]------------
>> RCU not on for: shared_cede_loop+0xc/0x170
>>
>> The code in question was added by
>> commit d099dbfd330686a8c09cd8944bcc77a56f9e7815
>> cpuidle: tracing: Warn about !rcu_is_watching()
>
> Note that by selecting ARCH_WANTS_NO_INSTR you effectively state to
> abide by its rules.
>
> 41b7a347bf14 ("powerpc: Book3S 64-bit outline-only KASAN support")
>
> AFAICT the power code does not even attempt to do this.
>
> For your idle path you want at least something like the below, but given
> you don't have build time validation of noinstr I can't really tell and
> you'll just have to run chase the stragglers.
>
Thanks for the feedback Peter. With the interim patch submitted by
Michael, I no longer see this warning.
next prev parent reply other threads:[~2023-02-02 14:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 8:16 WARN include/linux/trace_recursion.h:162 (powerpc) Sachin Sant
2023-02-02 8:56 ` Peter Zijlstra
2023-02-02 8:56 ` Peter Zijlstra
2023-02-02 14:01 ` Sachin Sant [this message]
2023-02-02 14:01 ` Sachin Sant
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