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From: sunliming <sunliming@kylinos.cn>
To: mhiramat@kernel.org, beaub@linux.microsoft.com,
	rostedt@goodmis.org, shuah@kernel.org
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
	linux-kselftest@vger.kernel.org, kelulanainsley@gmail.com,
	sunliming <sunliming@kylinos.cn>
Subject: [PATCH v3 1/4] tracing/user_events: Fix the incorrect trace record for empty arguments events
Date: Tue,  6 Jun 2023 14:20:24 +0800	[thread overview]
Message-ID: <20230606062027.1008398-2-sunliming@kylinos.cn> (raw)
In-Reply-To: <20230606062027.1008398-1-sunliming@kylinos.cn>

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(-)

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


  reply	other threads:[~2023-06-06  6:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-06  6:20 [PATCH v3 0/4] tracing/user_events: Add empty arguments events sunliming
2023-06-06  6:20 ` sunliming [this message]
2023-06-06  6:20 ` [PATCH v3 2/4] selftests/user_events: Add ftrace self-test for " sunliming
2023-06-06  6:20 ` [PATCH v3 3/4] selftests/user_events: Clear the events after perf self-test sunliming
2023-06-06  6:20 ` [PATCH v3 4/4] selftests/user_events: Add perf self-test for empty arguments events sunliming
2023-06-06 18:53 ` [PATCH v3 0/4] tracing/user_events: Add " Beau Belgrave
2023-06-07 14:10 ` Masami Hiramatsu

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