[PATCH 0/3] [GIT PULL] tracing: Three more updates

From: Steven Rostedt
Date: Sun May 22 2016 - 16:30:46 EST



Linus,

Three more changes.

1) I forgot that I had another selftest to stress test the ftrace
instance creation. It was actually suppose to go into the 4.6
merge window, but I never committed it. I almost forgot about it
again, but noticed it was missing from your tree.

2) Soumya PN sent me a clean up patch to not disable interrupts when
taking the tasklist_lock for read, as it's unnecessary because
that lock is never taken for write in irq context.

3) Newer gcc's can cause the jump in the function_graph code to the
global ftrace_stub label to be a short jump instead of a long one.
As that jump is dynamically converted to jump to the trace code to
do function graph tracing, and that conversion expects a long jump
it can corrupt the ftrace_stub itself (it's directly after that call).
One way to prevent gcc from using a short jump is to declare the
ftrace_stub as a weak function, which we do here to keep gcc from
optimizing too much.

Please pull the latest trace-v4.7-2 tree, which can be found at:


git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
trace-v4.7-2

Tag SHA1: 01ed489ad3660b3813d93d63b0b9258e08b15f7f
Head SHA1: 8329e818f14926a6040df86b2668568bde342ebf


Soumya PN (1):
ftrace: Don't disable irqs when taking the tasklist_lock read_lock

Steven Rostedt (1):
ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it

Steven Rostedt (Red Hat) (1):
ftracetest: Add instance created, delete, read and enable event test

----
arch/x86/kernel/mcount_64.S | 3 +-
kernel/trace/ftrace.c | 5 +-
.../ftrace/test.d/instances/instance-event.tc | 143 +++++++++++++++++++++
3 files changed, 147 insertions(+), 4 deletions(-)
create mode 100644 tools/testing/selftests/ftrace/test.d/instances/instance-event.tc