tracing: Do not warn when connecting eprobe to non existing event

7fa598f9 · Steven Rostedt (VMware) <[email protected]> · 2021-10-27 12:08:54 -04:00

When the syscall trace points are not configured in, the kselftests for
ftrace will try to attach an event probe (eprobe) to one of the system
call trace points. This triggered a WARNING, because the failure only
expects to see memory issues. But this is not the only failure. The user
may attempt to attach to a non existent event, and the kernel must not
warn about it.

Link: https://lkml.kernel.org/r/[email protected]

Fixes: 7491e2c442781 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

Commit: 7fa598f9706d40bd16f2ab286bdf5808e1393d35
Parents: 4e84dc47

Changes

1 files changed · +2 −2

File	Status	Add	Del	Content
kernel/trace/trace_eprobe.c	modified	+2	−2	View file

kernel/trace/trace_eprobe.c

View file

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index c4a15ae..5c5f208 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -904,8 +904,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 
 	if (IS_ERR(ep)) {
 		ret = PTR_ERR(ep);
-		/* This must return -ENOMEM, else there is a bug */
-		WARN_ON_ONCE(ret != -ENOMEM);
+		/* This must return -ENOMEM or misssing event, else there is a bug */
+		WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV);
 		ep = NULL;
 		goto error;
 	}