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Subject[PATCH 2/2] tracing/kprobes: Allow to create probe with a module name starting with a digit
From: Sabrina Dubroca <sd@queasysnail.net>

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

Cc: stable@vger.kernel.org
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>
---
kernel/trace/trace_kprobe.c | 14 +++++---------
1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index c129fca6ec99..b53c8d369163 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -707,20 +707,16 @@ static int create_trace_kprobe(int argc, char **argv)
pr_info("Probe point is not specified.\n");
return -EINVAL;
}
- if (isdigit(argv[1][0])) {
- /* an address specified */
- ret = kstrtoul(&argv[1][0], 0, (unsigned long *)&addr);
- if (ret) {
- pr_info("Failed to parse address.\n");
- return ret;
- }
- } else {
+
+ /* try to parse an address. if that fails, try to read the
+ * input as a symbol. */
+ if (kstrtoul(argv[1], 0, (unsigned long *)&addr)) {
/* a symbol specified */
symbol = argv[1];
/* TODO: support .init module functions */
ret = traceprobe_split_symbol_offset(symbol, &offset);
if (ret) {
- pr_info("Failed to parse symbol.\n");
+ pr_info("Failed to parse either an address or a symbol.\n");
return ret;
}
if (offset && is_return &&
--
2.10.2

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