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Subject[PATCH v3 1/4] trace/kprobes: Sanitize derived event names
Date
When we derive event names, convert some expected symbols (such as ':'
used to specify module:name and '.' present in some symbols) into
underscores so that the event name is not rejected.

Before this patch:
# echo 'p kobject_example:foo_store' > kprobe_events
trace_kprobe: Failed to allocate trace_probe.(-22)
-sh: write error: Invalid argument

After this patch:
# echo 'p kobject_example:foo_store' > kprobe_events
# cat kprobe_events
p:kprobes/p_kobject_example_foo_store_0 kobject_example:foo_store

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
kernel/trace/trace_kprobe.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index c129fca6ec99..44fd819aa33d 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -598,6 +598,14 @@ static struct notifier_block trace_kprobe_module_nb = {
.priority = 1 /* Invoked after kprobe module callback */
};

+/* Convert certain expected symbols into '_' when generating event names */
+static inline void sanitize_event_name(char *name)
+{
+ while (*name++ != '\0')
+ if (*name == ':' || *name == '.')
+ *name = '_';
+}
+
static int create_trace_kprobe(int argc, char **argv)
{
/*
@@ -740,6 +748,7 @@ static int create_trace_kprobe(int argc, char **argv)
else
snprintf(buf, MAX_EVENT_NAME_LEN, "%c_0x%p",
is_return ? 'r' : 'p', addr);
+ sanitize_event_name(buf);
event = buf;
}
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
--
2.13.2
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