[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240229143432.273b4871@gandalf.local.home>
Date: Thu, 29 Feb 2024 14:34:44 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>, netdev@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>, Mathieu Desnoyers
<mathieu.desnoyers@...icios.com>, Cong Wang <xiyou.wangcong@...il.com>,
vaclav.zindulka@...pnet.cz, Jamal Hadi Salim <jhs@...atatu.com>, Jiri
Pirko <jiri@...nulli.us>, "David S. Miller" <davem@...emloft.net>
Subject: [PATCH] tracing/net_sched: Fix tracepoints that save qdisc_dev() as
a string
From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
I'm updating __assign_str() and will be removing the second parameter. To
make sure that it does not break anything, I make sure that it matches the
__string() field, as that is where the string is actually going to be
saved in. To make sure there's nothing that breaks, I added a WARN_ON() to
make sure that what was used in __string() is the same that is used in
__assign_str().
In doing this change, an error was triggered as __assign_str() now expects
the string passed in to be a char * value. I instead had the following
warning:
include/trace/events/qdisc.h: In function ‘trace_event_raw_event_qdisc_reset’:
include/trace/events/qdisc.h:91:35: error: passing argument 1 of 'strcmp' from incompatible pointer type [-Werror=incompatible-pointer-types]
91 | __assign_str(dev, qdisc_dev(q));
That's because the qdisc_enqueue() and qdisc_reset() pass in qdisc_dev(q)
to __assign_str() and to __string(). But that function returns a pointer
to struct net_device and not a string.
It appears that these events are just saving the pointer as a string and
then reading it as a string as well.
Use qdisc_dev(q)->name to save the device instead.
Fixes: a34dac0b90552 ("net_sched: add tracepoints for qdisc_reset() and qdisc_destroy()")
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
include/trace/events/qdisc.h | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/include/trace/events/qdisc.h b/include/trace/events/qdisc.h
index a3995925cb05..1f4258308b96 100644
--- a/include/trace/events/qdisc.h
+++ b/include/trace/events/qdisc.h
@@ -81,14 +81,14 @@ TRACE_EVENT(qdisc_reset,
TP_ARGS(q),
TP_STRUCT__entry(
- __string( dev, qdisc_dev(q) )
- __string( kind, q->ops->id )
- __field( u32, parent )
- __field( u32, handle )
+ __string( dev, qdisc_dev(q)->name )
+ __string( kind, q->ops->id )
+ __field( u32, parent )
+ __field( u32, handle )
),
TP_fast_assign(
- __assign_str(dev, qdisc_dev(q));
+ __assign_str(dev, qdisc_dev(q)->name);
__assign_str(kind, q->ops->id);
__entry->parent = q->parent;
__entry->handle = q->handle;
@@ -106,14 +106,14 @@ TRACE_EVENT(qdisc_destroy,
TP_ARGS(q),
TP_STRUCT__entry(
- __string( dev, qdisc_dev(q) )
- __string( kind, q->ops->id )
- __field( u32, parent )
- __field( u32, handle )
+ __string( dev, qdisc_dev(q)->name )
+ __string( kind, q->ops->id )
+ __field( u32, parent )
+ __field( u32, handle )
),
TP_fast_assign(
- __assign_str(dev, qdisc_dev(q));
+ __assign_str(dev, qdisc_dev(q)->name);
__assign_str(kind, q->ops->id);
__entry->parent = q->parent;
__entry->handle = q->handle;
--
2.43.0
Powered by blists - more mailing lists