gala-gopher/fix-ksliprobe-get-invalid-args-occasionally-at-start.patch

From 6c2753778bcc7e124353a1e21612a1ebdb92f241 Mon Sep 17 00:00:00 2001
From: wo_cow <niuqianqian@huawei.com>
Date: Tue, 10 Jan 2023 22:39:28 +0800
Subject: [PATCH] fix ksliprobe get invalid args occasionally at startup

---
 src/common/args.c                             |  2 +-
 src/common/args.h                             |  2 +-
 .../ebpf.probe/src/ksliprobe/ksliprobe.bpf.c  | 20 ++++++++++++-------
 .../ebpf.probe/src/ksliprobe/ksliprobe.c      |  8 ++++----
 .../ebpf.probe/src/ksliprobe/ksliprobe.h      |  4 ++--
 5 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/src/common/args.c b/src/common/args.c
index 6c8e2d1..5c6bee7 100644
--- a/src/common/args.c
+++ b/src/common/args.c
@@ -157,7 +157,7 @@ static int __period_arg_parse(char opt, char *arg, struct probe_params *params)
             }
             break;
         case 'C':
-            params->cycle_sampling_flag = 1;
+            params->continuous_sampling_flag = 1;
             break;
         case 'k':
             params->kafka_port = (unsigned int)atoi(arg);
diff --git a/src/common/args.h b/src/common/args.h
index f8ab447..8fd5139 100644
--- a/src/common/args.h
+++ b/src/common/args.h
@@ -44,7 +44,7 @@ struct probe_params {
     char res_percent_upper;       // [-U <>] Upper limit of resource percentage, default is 0%
     char res_percent_lower;       // [-L <>] Lower limit of resource percentage, default is 0%
     unsigned char cport_flag;     // [-c <>] Indicates whether the probes(such as tcp) identifies the client port, default is 0 (no identify)
-    char cycle_sampling_flag;     // [-C <>] Enables the cycle sampling, default is 0
+    char continuous_sampling_flag;     // [-C <>] Enables the continuous sampling, default is 0
     char target_dev[DEV_NAME];    // [-d <>] Device name, default is null 
     char elf_path[MAX_PATH_LEN];  // [-p <>] Set ELF file path of the monitored software, default is null 
     char task_whitelist[MAX_PATH_LEN]; // [-w <>] Filtering app monitoring ranges, default is null
diff --git a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.bpf.c b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.bpf.c
index 6fa64ab..f54df41 100644
--- a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.bpf.c
+++ b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.bpf.c
@@ -116,17 +116,17 @@ static __always_inline void get_args(struct conn_data_t *conn_data)
 {
     u32 key = 0;
     u64 period = __PERIOD;
-    char cycle_sampling_flag = 0;
+    char continuous_sampling_flag = 0;
 
     struct ksli_args_s *args;
     args = (struct ksli_args_s *)bpf_map_lookup_elem(&args_map, &key);
     if (args) {
         period = args->period;
-        cycle_sampling_flag = args->cycle_sampling_flag;
+        continuous_sampling_flag = args->continuous_sampling_flag;
     }
 
     conn_data->report_period = period;
-    conn_data->cycle_sampling_flag = cycle_sampling_flag;
+    conn_data->continuous_sampling_flag = continuous_sampling_flag;
 
     return;
 }
@@ -262,7 +262,13 @@ static __always_inline int periodic_report(u64 ts_nsec, struct conn_data_t *conn
 {
     long err;
     int ret = 0;
-    u64 period = conn_data->report_period;
+
+    // period cannot be 0, so it is considered that the user mode has not written to args_map by now.
+    // therefore we try to get the value agagin.
+    if (conn_data->report_period == 0)
+        get_args(conn_data);
+
+    u64 period = (conn_data->report_period != 0) ? conn_data->report_period : __PERIOD;
 
     // 表示没有任何采样数据，不上报
     if (conn_data->latency.rtt_nsec == 0) {
@@ -299,7 +305,7 @@ static __always_inline void sample_finished(struct conn_data_t *conn_data, struc
         conn_data->latency.rtt_nsec = csd->rtt_ts_nsec;
         __builtin_memcpy(&conn_data->latency.command, &csd->command, MAX_COMMAND_REQ_SIZE);
     }
-    if (conn_data->cycle_sampling_flag) {
+    if (conn_data->continuous_sampling_flag) {
         if (conn_data->max.rtt_nsec < csd->rtt_ts_nsec) {
             conn_data->max.rtt_nsec = csd->rtt_ts_nsec;
             __builtin_memcpy(&conn_data->max.command, &csd->command, MAX_COMMAND_REQ_SIZE);
@@ -350,7 +356,7 @@ static __always_inline void process_rd_msg(u32 tgid, int fd, const char *buf, co
     }
 
     // 非循环采样每次上报后就返回，等待下次上报周期再采样。这种方式无法获取周期内max sli
-    if (!conn_data->cycle_sampling_flag && reported)
+    if (!conn_data->continuous_sampling_flag && reported)
         return;
 
     // 连接的协议类型未知时，连续3次read报文时解析不出是redis协议，就确认此条连接非redis请求连接，不做采样
@@ -403,7 +409,7 @@ KPROBE(ksys_read, pt_regs)
     if (conn_data->id.protocol == PROTOCOL_NO_REDIS)
         return;
 
-    if (!conn_data->cycle_sampling_flag) {
+    if (!conn_data->continuous_sampling_flag) {
         if (bpf_ktime_get_ns() - conn_data->last_report_ts_nsec < conn_data->report_period)
             return;
     }
diff --git a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.c b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.c
index d8221c9..ac8484e 100644
--- a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.c
+++ b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.c
@@ -40,7 +40,7 @@
 #define MAX_SLI_TBL_NAME "redis_max_sli"
 
 static volatile sig_atomic_t stop;
-static struct probe_params params = {.period = DEFAULT_PERIOD, .cycle_sampling_flag = 0};
+static struct probe_params params = {.period = DEFAULT_PERIOD, .continuous_sampling_flag = 0};
 
 static void sig_int(int signo)
 {
@@ -113,7 +113,7 @@ static void msg_event_handler(void *ctx, int cpu, void *data, unsigned int size)
             cli_ip_str,
             ntohs(msg_evt_data->client_ip_info.port),
             msg_evt_data->latency.rtt_nsec);
-    if (params.cycle_sampling_flag) {
+    if (params.continuous_sampling_flag) {
         fprintf(stdout,
             "|%s|%d|%d|%s|%s|%s|%u|%s|%u|%llu|\n",
             MAX_SLI_TBL_NAME,
@@ -173,7 +173,7 @@ static void load_args(int args_fd, struct probe_params* params)
     struct ksli_args_s args = {0};
 
     args.period = NS(params->period);
-    args.cycle_sampling_flag = params->cycle_sampling_flag;
+    args.continuous_sampling_flag = params->continuous_sampling_flag;
 
     (void)bpf_map_update_elem(args_fd, &key, &args, BPF_ANY);
 }
@@ -187,7 +187,7 @@ int main(int argc, char **argv)
         return -1;
     }
     printf("arg parse interval time:%us\n", params.period);
-    printf("arg parse if cycle sampling:%s\n", params.cycle_sampling_flag ? "true": "false");
+    printf("arg parse if cycle sampling:%s\n", params.continuous_sampling_flag ? "true": "false");
 
 #ifdef KERNEL_SUPPORT_TSTAMP
     load_tc_bpf(params.netcard_list, TC_PROG, TC_TYPE_INGRESS);
diff --git a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.h b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.h
index 40d2398..023e0e7 100644
--- a/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.h
+++ b/src/probes/extends/ebpf.probe/src/ksliprobe/ksliprobe.h
@@ -36,7 +36,7 @@
 
 struct ksli_args_s {
     __u64 period;        // Sampling period, unit ns
-    char cycle_sampling_flag;   // Enables the sampling of max sli within a period (which cause some performance degradation)
+    char continuous_sampling_flag;   // Enables the sampling of max sli within a period (which cause some performance degradation)
 };
 
 enum msg_event_rw_t {
@@ -89,7 +89,7 @@ struct conn_data_t {
     struct rtt_cmd_t current;
     __u64 last_report_ts_nsec;              // 上一次上报完成的时间点
     __u64 report_period;                    // 上报周期
-    char cycle_sampling_flag;
+    char continuous_sampling_flag;
     char procotol_check_times;
 };
 
-- 
2.33.0