Beau Belgrave beaub@linux.microsoft.com 于2023年6月9日周五 01:19写道：
On Thu, Jun 08, 2023 at 09:15:52AM +0800, sunliming wrote:
The writing operation return the count of writes whether events are enabled or disabled. This is incorrect when events are disabled. Fix this by just return -EFAULT when events are disabled.
Signed-off-by: sunliming sunliming@kylinos.cn
kernel/trace/trace_events_user.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c index 1ac5ba5685ed..970bac0503fd 100644 --- a/kernel/trace/trace_events_user.c +++ b/kernel/trace/trace_events_user.c @@ -1957,7 +1957,8 @@ static ssize_t user_events_write_core(struct file *file, struct iov_iter *i)
if (unlikely(faulted)) return -EFAULT;
}
} elsereturn -EFAULT;I'm not sure this is a good idea. Imagine this scenario: A user process writes out a user_event and it hits a fault that gets returned as errno (EFAULT).
The user process is likely to either forget it and say, not worth retrying, or it will retry (potentially in a loop).
If the process does retry and it's now disabled, it might try many times.
I think that -ENOENT is a better error to use here. That way a user process will know it got disabled mid-write vs a fault that might want to be re-attempted.
Thanks, -Beau
I think you are right. I have resend the V2 version of this series of patches based on suggestions, patches link : https://lore.kernel.org/linux-trace-kernel/20230609030302.1278716-1-sunlimin... Thanks.
return ret;}
2.25.1