Commit 5a90f577 authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

ftrace: print continue index fix 



An item in the trace buffer that is bigger than one entry may be split
up using the TRACE_CONT entry. This makes it a virtual single entry.
The current code increments the iterator index even while traversing
TRACE_CONT entries, making it look like the iterator is further than
it actually is.

This patch adds code to not increment the iterator index while skipping
over TRACE_CONT entries.

Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 652567aa

kernel/trace/trace.c

+10 −5
Original line number Diff line number Diff line
@@ -1117,9 +1117,8 @@ trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data, 
}



/* Increment the index counter of an iterator by one */

static void trace_iterator_increment(struct trace_iterator *iter, int cpu)

static void __trace_iterator_increment(struct trace_iterator *iter, int cpu)

{

	iter->idx++;

	iter->next_idx[cpu]++;

	iter->next_page_idx[cpu]++;
@@ -1132,6 +1131,12 @@ static void trace_iterator_increment(struct trace_iterator *iter, int cpu) 
	}

}



static void trace_iterator_increment(struct trace_iterator *iter, int cpu)

{

	iter->idx++;

	__trace_iterator_increment(iter, cpu);

}



static struct trace_entry *

trace_entry_next(struct trace_array *tr, struct trace_array_cpu *data,

		 struct trace_iterator *iter, int cpu)
@@ -1153,7 +1158,7 @@ trace_entry_next(struct trace_array *tr, struct trace_array_cpu *data, 


	/* find a real entry */

	do {

		trace_iterator_increment(iter, cpu);

		__trace_iterator_increment(iter, cpu);

		ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);

	} while (ent && ent->type != TRACE_CONT);
@@ -1187,7 +1192,7 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, int inc) 
				ent = trace_entry_next(tr, data, iter, cpu);

			else {

				while (ent && ent->type == TRACE_CONT) {

					trace_iterator_increment(iter, cpu);

					__trace_iterator_increment(iter, cpu);

					ent = trace_entry_idx(tr, tr->data[cpu],

							      iter, cpu);

				}
@@ -1566,7 +1571,7 @@ trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter) 


	do {

		trace_seq_printf(s, "%s", ent->cont.buf);

		trace_iterator_increment(iter, iter->cpu);

		__trace_iterator_increment(iter, iter->cpu);

		ent = trace_entry_idx(tr, data, iter, iter->cpu);

	} while (ent && ent->type == TRACE_CONT);

}

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