From: Yang Jihong <yangjihong1@xxxxxxxxxx>
[ Upstream commit f596da3efaf4130ff61cd029558845808df9bf99 ]
When the blk_classic option is enabled, non-blktrace events must be
filtered out. Otherwise, events of other types are output in the blktrace
classic format, which is unexpected.
The problem can be triggered in the following ways:
# echo 1 > /sys/kernel/debug/tracing/options/blk_classic
# echo 1 > /sys/kernel/debug/tracing/events/enable
# echo blk > /sys/kernel/debug/tracing/current_tracer
# cat /sys/kernel/debug/tracing/trace_pipe
Fixes: c71a89615411 ("blktrace: add ftrace plugin")
Signed-off-by: Yang Jihong <yangjihong1@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@xxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
kernel/trace/blktrace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a995ea1ef849..a66cff5a1857 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1548,7 +1548,8 @@ blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
{
- if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
+ if ((iter->ent->type != TRACE_BLK) ||
+ !(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
return TRACE_TYPE_UNHANDLED;
return print_one_line(iter, true);
--
2.35.1
