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From: Brian Foster <bfoster@redhat.com>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: linux-bcachefs@vger.kernel.org
Subject: Re: [BUG] trace_printk() broken?
Date: Wed, 14 Dec 2022 12:46:59 -0500	[thread overview]
Message-ID: <Y5oME9YVbg9Me2An@bfoster> (raw)
In-Reply-To: <Y5kLgQh3NVMmUr8W@moria.home.lan>

On Tue, Dec 13, 2022 at 06:32:17PM -0500, Kent Overstreet wrote:
> On Mon, Dec 12, 2022 at 02:20:39PM -0500, Brian Foster wrote:
> > Hi,
> > 
> > While poking around the bcachefs tree I ran into a problem where
> > trace_printk() seems to be broken. I suspect this has something to do
> > with the printbuf bits as it works once I back out some of those
> > changes.
> > 
> > What I observe is that a smaller printk with a fixed string seems to
> > work as expected, but once I add some variable args the message string
> > seems to get chewed up. This results in wonky formatting when reading
> > /sys/kernel/debug/tracing/trace and a read of the corresponding
> > trace_pipe file seems to spin in a livelock.
> 
> I recently noticed it was broken too, but different symptoms - I wasn't getting
> any output at all. Thanks for the reminder, I'll have a look soon.
> 

Thanks. Just to be clear, I saw no output from trace_pipe. The separate
.../tracing/trace file is where I observed the wonky event formatting.

Brian


      reply	other threads:[~2022-12-14 17:47 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-12 19:20 [BUG] trace_printk() broken? Brian Foster
2022-12-13 23:32 ` Kent Overstreet
2022-12-14 17:46   ` Brian Foster [this message]

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