diff mbox series

[V2,1/4] tracing/user_events: Fix the incorrect trace record for empty arguments events

Message ID 20230605073023.923316-1-sunliming@kylinos.cn
State New
Headers
Series [V2,1/4] tracing/user_events: Fix the incorrect trace record for empty arguments events |

Commit Message

sunliming June 5, 2023, 7:30 a.m. UTC 
  The user_events support events that has empty arguments. But the trace event
is discarded and not really committed when the arguments is empty. Fix this
by not attempting to copy in zero-length data.

Signed-off-by: sunliming <sunliming@kylinos.cn>
---
 kernel/trace/trace_events_user.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Beau Belgrave June 5, 2023, 4:52 p.m. UTC | #1 
On Mon, Jun 05, 2023 at 03:30:20PM +0800, sunliming wrote:
> The user_events support events that has empty arguments. But the trace event
> is discarded and not really committed when the arguments is empty. Fix this
> by not attempting to copy in zero-length data.
> 
> Signed-off-by: sunliming <sunliming@kylinos.cn>
> ---

This series looks good to me, functionally. I applied it locally and ran
this code with the new test additions. Everything works well. Thank you!

The only thing I ask before an ACK is patch 2 and 4 in the series only use
"user_events: " prefix. Can you change these to "selftests/user_events: "?

You marked 3 this way, so I'd like to stick with a consistent form:
I think it would be good going forward we use "tracing/user_events"
for functional changes and "selftests/user_events" for self test
changes.

Thanks,
-Beau

>  kernel/trace/trace_events_user.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
> index 0d91dac206ff..698703a3d234 100644
> --- a/kernel/trace/trace_events_user.c
> +++ b/kernel/trace/trace_events_user.c
> @@ -1399,7 +1399,7 @@ static void user_event_ftrace(struct user_event *user, struct iov_iter *i,
>  	if (unlikely(!entry))
>  		return;
>  
> -	if (unlikely(!copy_nofault(entry + 1, i->count, i)))
> +	if (unlikely(i->count != 0 && !copy_nofault(entry + 1, i->count, i)))
>  		goto discard;
>  
>  	if (!list_empty(&user->validators) &&
> @@ -1440,7 +1440,7 @@ static void user_event_perf(struct user_event *user, struct iov_iter *i,
>  
>  		perf_fetch_caller_regs(regs);
>  
> -		if (unlikely(!copy_nofault(perf_entry + 1, i->count, i)))
> +		if (unlikely(i->count != 0 && !copy_nofault(perf_entry + 1, i->count, i)))
>  			goto discard;
>  
>  		if (!list_empty(&user->validators) &&
> -- 
> 2.25.1
diff mbox series

Patch

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 0d91dac206ff..698703a3d234 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1399,7 +1399,7 @@  static void user_event_ftrace(struct user_event *user, struct iov_iter *i,
 	if (unlikely(!entry))
 		return;
 
-	if (unlikely(!copy_nofault(entry + 1, i->count, i)))
+	if (unlikely(i->count != 0 && !copy_nofault(entry + 1, i->count, i)))
 		goto discard;
 
 	if (!list_empty(&user->validators) &&
@@ -1440,7 +1440,7 @@  static void user_event_perf(struct user_event *user, struct iov_iter *i,
 
 		perf_fetch_caller_regs(regs);
 
-		if (unlikely(!copy_nofault(perf_entry + 1, i->count, i)))
+		if (unlikely(i->count != 0 && !copy_nofault(perf_entry + 1, i->count, i)))
 			goto discard;
 
 		if (!list_empty(&user->validators) &&