tracing/kprobes: Allow to create probe with a module name starting with a digit

tracing/kprobes: Allow to create probe with a module name starting with a digit

commit 9e52b32567126fe146f198971364f68d3bc5233f upstream.

Always try to parse an address, since kstrtoul() will safely fail when
given a symbol as input. If that fails (which will be the case for a
symbol), try to parse a symbol instead.

This allows creating a probe such as:

    p:probe/vlan_gro_receive 8021q:vlan_gro_receive+0

Which is necessary for this command to work:

    perf probe -m 8021q -a vlan_gro_receive

Link: http://lkml.kernel.org/r/fd72d666f45b114e2c5b9cf7e27b91de1ec966f1.1498122881.git.sd@queasysnail.net
Fixes: 413d37d1e ("tracing: Add kprobe-based event tracer")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.2: preserve the check that an addresses isn't used for
 a kretprobe]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>