[RFC PATCH v2 5/7] tracing/probe: Verify alloc_trace_*probe() result

Masami Hiramatsu
2019-03-14T04:30:57Z

Since alloc_trace_*probe() returns -EINVAL only if !event && !group,
it should not happen in trace_*probe_create(). If we catch that case
there is a bug. So use WARN_ON_ONCE() instead of pr_info().

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/trace/trace_kprobe.c | 4 ++--
kernel/trace/trace_uprobe.c | 3 ++-
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 5222fd82e7e4..56324c231688 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -693,9 +693,9 @@ static int trace_kprobe_create(int argc, const char *argv[])
tk = alloc_trace_kprobe(group, event, addr, symbol, offset, maxactive,
argc, is_return);
if (IS_ERR(tk)) {
- pr_info("Failed to allocate trace_probe.(%d)\n",
- (int)PTR_ERR(tk));
ret = PTR_ERR(tk);
+ /* This must return -ENOMEM otherwise there is a bug */
+ WARN_ON_ONCE(ret != -ENOMEM);
goto out;
}

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 52f033489377..b54137ec7810 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -514,8 +514,9 @@ static int trace_uprobe_create(int argc, const char **argv)

tu = alloc_trace_uprobe(group, event, argc, is_return);
if (IS_ERR(tu)) {
- pr_info("Failed to allocate trace_uprobe.(%d)\n", (int)PTR_ERR(tu));
ret = PTR_ERR(tu);
+ /* This must return -ENOMEM otherwise there is a bug */
+ WARN_ON_ONCE(ret != -ENOMEM);
goto fail_address_parse;
}
tu->offset = offset;