From: Yang Jihong yangjihong1@huawei.com
[ 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@huawei.com Link: https://lore.kernel.org/r/20221122040410.85113-1-yangjihong1@huawei.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- 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 0b22bf622397..30e3af538039 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -1612,7 +1612,8 @@ 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);