powerpc/kprobes: Disable preemption before invoking probe handler for optprobes
authorNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Mon, 23 Oct 2017 16:37:38 +0000 (22:07 +0530)
committerMichael Ellerman <mpe@ellerman.id.au>
Sun, 12 Nov 2017 12:51:40 +0000 (23:51 +1100)
commit8a2d71a3f2737e2448aa68de2b6052cb570d3d2a
treef51a9abf2998ac22df6bc90d135b9359b1a11d0d
parentfc2a5a6161a26b386eb0936b74a852ff83793fb6
powerpc/kprobes: Disable preemption before invoking probe handler for optprobes

Per Documentation/kprobes.txt, probe handlers need to be invoked with
preemption disabled. Update optimized_callback() to do so. Also move
get_kprobe_ctlblk() invocation post preemption disable, since it
accesses pre-cpu data.

This was not an issue so far since optprobes wasn't selected if
CONFIG_PREEMPT was enabled. Commit a30b85df7d599f ("kprobes: Use
synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT=y") changes
this.

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/kernel/optprobes.c