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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-22 19:40:39 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-22 19:40:39 -0700 |
commit | 7639dad93a5564579987abded4ec05e3db13659d (patch) | |
tree | d786a45e79672ee3ea04e93d60ec1da02cb17940 /kernel | |
parent | 77ed402b7f53cbe50ae8384a172a5b9713020400 (diff) | |
parent | 8329e818f14926a6040df86b2668568bde342ebf (diff) | |
download | op-kernel-dev-7639dad93a5564579987abded4ec05e3db13659d.zip op-kernel-dev-7639dad93a5564579987abded4ec05e3db13659d.tar.gz |
Merge tag 'trace-v4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull motr tracing updates from Steven Rostedt:
"Three more changes.
- 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.
- 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.
- 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"
* tag 'trace-v4.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace/x86: Set ftrace_stub to weak to prevent gcc from using short jumps to it
ftrace: Don't disable irqs when taking the tasklist_lock read_lock
ftracetest: Add instance created, delete, read and enable event test
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/ftrace.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a6c8252..900dbb1 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5737,7 +5737,6 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) { int i; int ret = 0; - unsigned long flags; int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE; struct task_struct *g, *t; @@ -5753,7 +5752,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) } } - read_lock_irqsave(&tasklist_lock, flags); + read_lock(&tasklist_lock); do_each_thread(g, t) { if (start == end) { ret = -EAGAIN; @@ -5771,7 +5770,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list) } while_each_thread(g, t); unlock: - read_unlock_irqrestore(&tasklist_lock, flags); + read_unlock(&tasklist_lock); free: for (i = start; i < end; i++) kfree(ret_stack_list[i]); |