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Two more small fixes. 

One is by Yang Shi who added a READ_ONCE_NOCHECK() to the scan of the
 stack made by the stack tracer. As the stack tracer scans the entire
 kernel stack, KASAN triggers seeing it as a "stack out of bounds" error.
 As the scan is looking at the contents of the stack from parent functions.
 The NOCHECK() tells KASAN that this is done on purpose, and is not some
 kind of stack overflow.
 
 The second fix is to the ftrace selftests, to retrieve the PID of executed
 commands from the shell with "$!" and not by parsing "jobs".
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Merge tag 'trace-fixes-v4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "Two more small fixes.

  One is by Yang Shi who added a READ_ONCE_NOCHECK() to the scan of the
  stack made by the stack tracer.  As the stack tracer scans the entire
  kernel stack, KASAN triggers seeing it as a "stack out of bounds"
  error.  As the scan is looking at the contents of the stack from
  parent functions.  The NOCHECK() tells KASAN that this is done on
  purpose, and is not some kind of stack overflow.

  The second fix is to the ftrace selftests, to retrieve the PID of
  executed commands from the shell with '$!' and not by parsing 'jobs'"

* tag 'trace-fixes-v4.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing, kasan: Silence Kasan warning in check_stack of stack_tracer
  ftracetest: Fix instance test to use proper shell command for pids
This commit is contained in:
Linus Torvalds 2016-02-22 14:09:18 -08:00
parent 692b8c663c 6e22c83664
commit 4de8ebeff8
2 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
kernel/trace/trace_stack.c
View File

@ -156,7 +156,11 @@ check_stack(unsigned long ip, unsigned long *stack)
for (; p < top && i < stack_trace_max.nr_entries; p++) {
if (stack_dump_trace[i] == ULONG_MAX)
break;
if (*p == stack_dump_trace[i]) {
/*
* The READ_ONCE_NOCHECK is used to let KASAN know that
* this is not a stack-out-of-bounds error.
*/
if ((READ_ONCE_NOCHECK(*p)) == stack_dump_trace[i]) {
stack_dump_trace[x] = stack_dump_trace[i++];
this_size = stack_trace_index[x++] =
(top - p) * sizeof(unsigned long);

15
tools/testing/selftests/ftrace/test.d/instances/instance.tc
View File

@ -39,28 +39,23 @@ instance_slam() {
}
instance_slam &
x=`jobs -l`
p1=`echo $x | cut -d' ' -f2`
p1=$!
echo $p1
instance_slam &
x=`jobs -l | tail -1`
p2=`echo $x | cut -d' ' -f2`
p2=$!
echo $p2
instance_slam &
x=`jobs -l | tail -1`
p3=`echo $x | cut -d' ' -f2`
p3=$!
echo $p3
instance_slam &
x=`jobs -l | tail -1`
p4=`echo $x | cut -d' ' -f2`
p4=$!
echo $p4
instance_slam &
x=`jobs -l | tail -1`
p5=`echo $x | cut -d' ' -f2`
p5=$!
echo $p5
ls -lR >/dev/null