From: Chuck Lever III <chuck.lever@oracle.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: possible trace_printk() bug in v5.19-rc1
Date: Thu, 16 Jun 2022 15:36:43 +0000 [thread overview]
Message-ID: <E309A098-DA06-490D-A75C-E6295C2987B9@oracle.com> (raw)
In-Reply-To: <20220616113400.15335d91@gandalf.local.home>
> On Jun 16, 2022, at 11:34 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 16 Jun 2022 15:22:26 +0000
> Chuck Lever III <chuck.lever@oracle.com> wrote:
>
>> Hi Steve-
>>
>> Since v5.19-rc1, trace_printk() no longer displays a function
>> name, but rather a kernel address. I don't have time at the
>> moment to track this down to a specific commit, just parking
>> it here in case someone can get to it sooner than me.
>>
>> <idle>-0 [003] 269.397568: bprint: 0xffffffffc0cccab7: nf=0xffff888172dbfba0 still on the LRU or a dispose list
>> <idle>-0 [003] 269.397576: bprint: 0xffffffffc0cccafa: nf=0xffff888172dbfba0
>> <idle>-0 [003] 269.397583: bprint: 0xffffffffc0cccab7: nf=0xffff8881726cd4d8 still on the LRU or a dispose list
>> <idle>-0 [003] 269.397584: bprint: 0xffffffffc0cccafa: nf=0xffff8881726cd4d8
>>
>
> It uses the normal vsprintf() in the kernel (that is, it prints the
> function address just like printk() does with %pS). So if trace_printk() is
> broken, then so is printk().
>
> But one reason for this is if you have a trace_printk() in a module, do the
> record, and then remove the module. The function name will also be removed
> from kallsyms, leaving you with only the function address.
>
> Did you remove any modules before displaying the trace?
I haven't explicitly removed nfsd.ko, and lsmod says it's still there.
And, trace_printk was working as expected on v5.18.
--
Chuck Lever
next prev parent reply other threads:[~2022-06-16 15:36 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 15:22 possible trace_printk() bug in v5.19-rc1 Chuck Lever III
2022-06-16 15:34 ` Steven Rostedt
2022-06-16 15:36 ` Chuck Lever III [this message]
2022-06-16 15:43 ` Steven Rostedt
2022-06-16 18:07 ` Chuck Lever III
2022-06-17 19:50 ` Steven Rostedt
2022-06-18 1:28 ` Chuck Lever III
2022-06-20 0:57 ` Chuck Lever III
2022-06-24 18:23 ` Chuck Lever III
2022-06-24 23:08 ` Steven Rostedt
2022-06-25 17:15 ` Chuck Lever III
2022-06-25 17:45 ` Steven Rostedt
2022-06-25 18:28 ` John 'Warthog9' Hawley
2022-06-26 3:01 ` John 'Warthog9' Hawley
2022-06-27 17:08 ` Chuck Lever III
2022-06-27 17:11 ` Steven Rostedt
2022-06-27 17:19 ` Chuck Lever III
2022-06-27 19:01 ` Steven Rostedt
2022-06-28 15:24 ` Steven Rostedt
2022-06-25 18:50 ` Chuck Lever III
2022-06-25 23:01 ` Steven Rostedt
2022-06-26 17:09 ` Chuck Lever III
2022-06-27 15:43 ` Steven Rostedt
2022-06-27 15:51 ` Chuck Lever III
2022-06-27 16:02 ` Steven Rostedt
2022-06-28 3:59 ` Steven Rostedt
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