From 36c8fb2c616d9373758b155d9723774353067a87 Mon Sep 17 00:00:00 2001 From: Thiago Jung Bauermann Date: Thu, 29 Jun 2017 18:55:32 -0300 Subject: [PATCH] powerpc/perf/hv-24x7: Fix off-by-one error in request_buffer check request_buffer can hold 254 requests, so if it already has that number of entries we can't add a new one. Also, define constant to show where the number comes from. Fixes: e3ee15dc5d19 ("powerpc/perf/hv-24x7: Define add_event_to_24x7_request()") Reviewed-by: Sukadev Bhattiprolu Signed-off-by: Thiago Jung Bauermann Signed-off-by: Michael Ellerman --- arch/powerpc/perf/hv-24x7.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 1354cde7095c..141de0f708f7 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -166,6 +166,10 @@ DEFINE_PER_CPU(struct hv_24x7_hw, hv_24x7_hw); DEFINE_PER_CPU(char, hv_24x7_reqb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096); DEFINE_PER_CPU(char, hv_24x7_resb[H24x7_DATA_BUFFER_SIZE]) __aligned(4096); +#define MAX_NUM_REQUESTS ((H24x7_DATA_BUFFER_SIZE - \ + sizeof(struct hv_24x7_request_buffer)) \ + / sizeof(struct hv_24x7_request)) + static char *event_name(struct hv_24x7_event_data *ev, int *len) { *len = be16_to_cpu(ev->event_name_len) - 2; @@ -1107,7 +1111,7 @@ static int add_event_to_24x7_request(struct perf_event *event, int i; struct hv_24x7_request *req; - if (request_buffer->num_requests > 254) { + if (request_buffer->num_requests >= MAX_NUM_REQUESTS) { pr_devel("Too many requests for 24x7 HCALL %d\n", request_buffer->num_requests); return -EINVAL; -- 2.20.1