[PATCH REPOST] usb: udc: Make tracing aware that usb_ep_alloc_request() can return NULL

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

The alloc_request callback of the EP can return NULL if it was not able
to allocate a request. This NULL pointer will then be dereferenced by
tracing in order to show details about it.

Let tracing check the req pointer and if NULL just write 0.

Fixes: 5e42d710a108c ("usb: gadget: add tracepoints to the gadget API")
Reported-by: syzbot+de553c19cb054f174a35@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/6aab0160.e91c2013.3bdb06.0005.GAE@google.com/
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/usb/gadget/udc/trace.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/gadget/udc/trace.h b/drivers/usb/gadget/udc/trace.h
index fa3e6ddf0a128..05533eb1bae0c 100644
--- a/drivers/usb/gadget/udc/trace.h
+++ b/drivers/usb/gadget/udc/trace.h
@@ -239,15 +239,15 @@ DECLARE_EVENT_CLASS(udc_log_req,
 	),
 	TP_fast_assign(
 		__assign_str(name);
-		__entry->length = req->length;
-		__entry->actual = req->actual;
-		__entry->num_sgs = req->num_sgs;
-		__entry->num_mapped_sgs = req->num_mapped_sgs;
-		__entry->stream_id = req->stream_id;
-		__entry->no_interrupt = req->no_interrupt;
-		__entry->zero = req->zero;
-		__entry->short_not_ok = req->short_not_ok;
-		__entry->status = req->status;
+		__entry->length = req ? req->length : 0;
+		__entry->actual = req ? req->actual : 0;
+		__entry->num_sgs = req ? req->num_sgs : 0;
+		__entry->num_mapped_sgs = req ? req->num_mapped_sgs : 0;
+		__entry->stream_id = req ? req->stream_id : 0;
+		__entry->no_interrupt = req ? req->no_interrupt : 0;
+		__entry->zero = req ? req->zero : 0;
+		__entry->short_not_ok = req ? req->short_not_ok : 0;
+		__entry->status = req ? req->status : 0;
 		__entry->ret = ret;
 		__entry->req = req;
 	),
-- 
2.55.0