Do not WARN when attaching event probe to non-existent event

If the user tries to attach an event probe (eprobe) to an event that does
 not exist, it will trigger a warning. There's an error check that only
 expects memory issues otherwise it is considered a bug. But changes in the
 code to move around the locking made it that it can error out if the user
 attempts to attach to an event that does not exist, returning an -ENODEV.
 As this path can be caused by user space putting in a bad value, do not
 trigger a WARN.
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Merge tag 'trace-v5.15-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Do not WARN when attaching event probe to non-existent event

  If the user tries to attach an event probe (eprobe) to an event that
  does not exist, it will trigger a warning. There's an error check that
  only expects memory issues otherwise it is considered a bug. But
  changes in the code to move around the locking made it that it can
  error out if the user attempts to attach to an event that does not
  exist, returning an -ENODEV. As this path can be caused by user space
  putting in a bad value, do not trigger a WARN"

* tag 'trace-v5.15-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Do not warn when connecting eprobe to non existing event
This commit is contained in:
Linus Torvalds 2021-10-28 09:50:56 -07:00
commit fc18cc89b9

View file

@ -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;
}