[tip: perf/core] perf: Make rb_alloc_aux() return an error immediately if nr_pages <= 0

[tip-bot2 for Adrian Hunter]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     0ca4da2412da05fb9dd0b5d90dcc8026219f0f29
Gitweb:        https://git.kernel.org/tip/0ca4da2412da05fb9dd0b5d90dcc8026219f0f29
Author:        Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate:    Mon, 24 Jun 2024 23:11:01 +03:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 04 Jul 2024 16:00:23 +02:00

perf: Make rb_alloc_aux() return an error immediately if nr_pages <= 0

rb_alloc_aux() should not be called with nr_pages <= 0. Make it more robust
and readable by returning an error immediately in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240624201101.60186-8-adrian.hunter@xxxxxxxxx
---
 kernel/events/ring_buffer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 485cf0a..8cadf97 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -682,6 +682,9 @@ int rb_alloc_aux(struct perf_buffer *rb, struct perf_event *event,
 	if (!has_aux(event))
 		return -EOPNOTSUPP;
 
+	if (nr_pages <= 0)
+		return -EINVAL;
+
 	if (!overwrite) {
 		/*
 		 * Watermark defaults to half the buffer, and so does the