Merge tag 'trace-v6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull tracing fixes from Steven Rostedt:

 - Fix eventfs to check creating new files for events with names greater
   than NAME_MAX. The eventfs lookup needs to check the return result of
   simple_lookup().

 - Fix the ring buffer to check the proper max data size. Events must be
   able to fit on the ring buffer sub-buffer, if it cannot, then it
   fails to be written and the logic to add the event is avoided. The
   code to check if an event can fit failed to add the possible absolute
   timestamp which may make the event not be able to fit. This causes
   the ring buffer to go into an infinite loop trying to find a
   sub-buffer that would fit the event. Luckily, there's a check that
   will bail out if it looped over a 1000 times and it also warns.

   The real fix is not to add the absolute timestamp to an event that is
   starting at the beginning of a sub-buffer because it uses the
   sub-buffer timestamp.

   By avoiding the timestamp at the start of the sub-buffer allows
   events that pass the first check to always find a sub-buffer that it
   can fit on.

 - Have large events that do not fit on a trace_seq to print "LINE TOO
   BIG" like it does for the trace_pipe instead of what it does now
   which is to silently drop the output.

 - Fix a memory leak of forgetting to free the spare page that is saved
   by a trace instance.

 - Update the size of the snapshot buffer when the main buffer is
   updated if the snapshot buffer is allocated.

 - Fix ring buffer timestamp logic by removing all the places that tried
   to put the before_stamp back to the write stamp so that the next
   event doesn't add an absolute timestamp. But each of these updates
   added a race where by making the two timestamp equal, it was
   validating the write_stamp so that it can be incorrectly used for
   calculating the delta of an event.

 - There's a temp buffer used for printing the event that was using the
   event data size for allocation when it needed to use the size of the
   entire event (meta-data and payload data)

 - For hardening, use "%.*s" for printing the trace_marker output, to
   limit the amount that is printed by the size of the event. This was
   discovered by development that added a bug that truncated the '\0'
   and caused a crash.

 - Fix a use-after-free bug in the use of the histogram files when an
   instance is being removed.

 - Remove a useless update in the rb_try_to_discard of the write_stamp.
   The before_stamp was already changed to force the next event to add
   an absolute timestamp that the write_stamp is not used. But the
   write_stamp is modified again using an unneeded 64-bit cmpxchg.

 - Fix several races in the 32-bit implementation of the
   rb_time_cmpxchg() that does a 64-bit cmpxchg.

 - While looking at fixing the 64-bit cmpxchg, I noticed that because
   the ring buffer uses normal cmpxchg, and this can be done in NMI
   context, there's some architectures that do not have a working
   cmpxchg in NMI context. For these architectures, fail recording
   events that happen in NMI context.

* tag 'trace-v6.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI
  ring-buffer: Have rb_time_cmpxchg() set the msb counter too
  ring-buffer: Fix 32-bit rb_time_read() race with rb_time_cmpxchg()
  ring-buffer: Fix a race in rb_time_cmpxchg() for 32 bit archs
  ring-buffer: Remove useless update to write_stamp in rb_try_to_discard()
  ring-buffer: Do not try to put back write_stamp
  tracing: Fix uaf issue when open the hist or hist_debug file
  tracing: Add size check when printing trace_marker output
  ring-buffer: Have saved event hold the entire event
  ring-buffer: Do not update before stamp when switching sub-buffers
  tracing: Update snapshot buffer on resize if it is allocated
  ring-buffer: Fix memory leak of free page
  eventfs: Fix events beyond NAME_MAX blocking tasks
  tracing: Have large events show up as '[LINE TOO BIG]' instead of nothing
  ring-buffer: Fix writing to the buffer with max_data_size

1 files changed, 13 insertions, 3 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index fbcd3bafb93e..199df497db07 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4722,7 +4722,11 @@ static int s_show(struct seq_file *m, void *v)
 		iter->leftover = ret;
 
 	} else {
-		print_trace_line(iter);
+		ret = print_trace_line(iter);
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			iter->seq.full = 0;
+			trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
+		}
 		ret = trace_print_seq(m, &iter->seq);
 		/*
 		 * If we overflow the seq_file buffer, then it will
@@ -4964,6 +4968,12 @@ int tracing_release_file_tr(struct inode *inode, struct file *filp)
 	return 0;
 }
 
+int tracing_single_release_file_tr(struct inode *inode, struct file *filp)
+{
+	tracing_release_file_tr(inode, filp);
+	return single_release(inode, filp);
+}
+
 static int tracing_mark_open(struct inode *inode, struct file *filp)
 {
 	stream_open(inode, filp);
@@ -6344,7 +6354,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr,
 	if (!tr->array_buffer.buffer)
 		return 0;
 
-	/* Do not allow tracing while resizng ring buffer */
+	/* Do not allow tracing while resizing ring buffer */
 	tracing_stop_tr(tr);
 
 	ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu);
@@ -6352,7 +6362,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr,
 		goto out_start;
 
 #ifdef CONFIG_TRACER_MAX_TRACE
-	if (!tr->current_trace->use_max_tr)
+	if (!tr->allocated_snapshot)
 		goto out;
 
 	ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);