powerpc/kprobes: Pause function_graph tracing during jprobes handling
authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Thu, 1 Jun 2017 10:48:15 +0000 (16:18 +0530)
committerMichael Ellerman <mpe@ellerman.id.au>
Fri, 16 Jun 2017 09:49:43 +0000 (19:49 +1000)
commita9f8553e935f26cb5447f67e280946b0923cd2dc
tree50d94ef8c3ffe08b34b9ae3e9993c140733b1a61
parenta093c92dc7f96a15de98ec8cfe38e6f7610a5969
powerpc/kprobes: Pause function_graph tracing during jprobes handling

This fixes a crash when function_graph and jprobes are used together.
This is essentially commit 237d28db036e ("ftrace/jprobes/x86: Fix
conflict between jprobes and function graph tracing"), but for powerpc.

Jprobes breaks function_graph tracing since the jprobe hook needs to use
jprobe_return(), which never returns back to the hook, but instead to
the original jprobe'd function. The solution is to momentarily pause
function_graph tracing before invoking the jprobe hook and re-enable it
when returning back to the original jprobe'd function.

Fixes: 6794c78243bf ("powerpc64: port of the function graph tracer")
Cc: stable@vger.kernel.org # v2.6.30+
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/kernel/kprobes.c