From: "Steven Rostedt (Google)" rostedt@goodmis.org
[ Upstream commit 51270d573a8d9dd5afdc7934de97d66c0e14b5fd ]
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@goodmis.org Reviewed-by: Jamal Hadi Salim jhs@mojatatu.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.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 59c945b66f9c7..5180da19d837f 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;