diff options
| -rw-r--r-- | kernel/trace/trace.c | 59 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 4 |
2 files changed, 36 insertions, 27 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 2e87b7bf2ba7..e3b8c906b7b4 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -980,6 +980,8 @@ __buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *ev ring_buffer_write(buffer, event->array[0], &event->array[1]); /* Release the temp buffer */ this_cpu_dec(trace_buffered_event_cnt); + /* ring_buffer_unlock_commit() enables preemption */ + preempt_enable_notrace(); } else ring_buffer_unlock_commit(buffer, event); } @@ -2745,8 +2747,8 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, *current_rb = tr->array_buffer.buffer; if (!tr->no_filter_buffering_ref && - (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) && - (entry = __this_cpu_read(trace_buffered_event))) { + (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) { + preempt_disable_notrace(); /* * Filtering is on, so try to use the per cpu buffer first. * This buffer will simulate a ring_buffer_event, @@ -2764,33 +2766,38 @@ trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, * is still quicker than no copy on match, but having * to discard out of the ring buffer on a failed match. */ - int max_len = PAGE_SIZE - struct_size(entry, array, 1); + if ((entry = __this_cpu_read(trace_buffered_event))) { + int max_len = PAGE_SIZE - struct_size(entry, array, 1); - val = this_cpu_inc_return(trace_buffered_event_cnt); + val = this_cpu_inc_return(trace_buffered_event_cnt); - /* - * Preemption is disabled, but interrupts and NMIs - * can still come in now. If that happens after - * the above increment, then it will have to go - * back to the old method of allocating the event - * on the ring buffer, and if the filter fails, it - * will have to call ring_buffer_discard_commit() - * to remove it. - * - * Need to also check the unlikely case that the - * length is bigger than the temp buffer size. - * If that happens, then the reserve is pretty much - * guaranteed to fail, as the ring buffer currently - * only allows events less than a page. But that may - * change in the future, so let the ring buffer reserve - * handle the failure in that case. - */ - if (val == 1 && likely(len <= max_len)) { - trace_event_setup(entry, type, trace_ctx); - entry->array[0] = len; - return entry; + /* + * Preemption is disabled, but interrupts and NMIs + * can still come in now. If that happens after + * the above increment, then it will have to go + * back to the old method of allocating the event + * on the ring buffer, and if the filter fails, it + * will have to call ring_buffer_discard_commit() + * to remove it. + * + * Need to also check the unlikely case that the + * length is bigger than the temp buffer size. + * If that happens, then the reserve is pretty much + * guaranteed to fail, as the ring buffer currently + * only allows events less than a page. But that may + * change in the future, so let the ring buffer reserve + * handle the failure in that case. + */ + if (val == 1 && likely(len <= max_len)) { + trace_event_setup(entry, type, trace_ctx); + entry->array[0] = len; + /* Return with preemption disabled */ + return entry; + } + this_cpu_dec(trace_buffered_event_cnt); } - this_cpu_dec(trace_buffered_event_cnt); + /* __trace_buffer_lock_reserve() disables preemption */ + preempt_enable_notrace(); } entry = __trace_buffer_lock_reserve(*current_rb, type, len, diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 7162157b970b..8bd1a815ce90 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1337,10 +1337,12 @@ __trace_event_discard_commit(struct trace_buffer *buffer, struct ring_buffer_event *event) { if (this_cpu_read(trace_buffered_event) == event) { - /* Simply release the temp buffer */ + /* Simply release the temp buffer and enable preemption */ this_cpu_dec(trace_buffered_event_cnt); + preempt_enable_notrace(); return; } + /* ring_buffer_discard_commit() enables preemption */ ring_buffer_discard_commit(buffer, event); } |