From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 0/3] [GIT PULL] tracing: Three more updates
Date: Sun, 22 May 2016 16:28:46 -0400 [thread overview]
Message-ID: <20160522202846.576089843@goodmis.org> (raw)
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
next reply other threads:[~2016-05-22 20:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-22 20:28 Steven Rostedt [this message]
2016-05-22 20:28 ` [PATCH 1/3] ftracetest: Add instance created, delete, read and enable event test Steven Rostedt
2016-05-22 20:28 ` [PATCH 2/3] ftrace: Dont disable irqs when taking the tasklist_lock read_lock Steven Rostedt
2016-05-22 20:28 ` [PATCH 3/3] ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it Steven Rostedt
2016-06-20 0:46 ` Namhyung Kim
2016-06-20 13:40 ` Steven Rostedt
-- strict thread matches above, loose matches on Subject: below --
2019-12-05 2:04 [PATCH 0/3] [GIT PULL] tracing: three more updates Steven Rostedt
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