From da0f1f4167e3af69e1d8b32d6d65195ddd2bfb64 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Sat, 25 Apr 2020 14:49:17 +0900 Subject: [PATCH] tracing/boottime: Fix kprobe event API usage Fix boottime kprobe events to use API correctly for multiple events. For example, when we set a multiprobe kprobe events in bootconfig like below, ftrace.event.kprobes.myevent { probes = "vfs_read $arg1 $arg2", "vfs_write $arg1 $arg2" } This cause an error; trace_boot: Failed to add probe: p:kprobes/myevent (null) vfs_read $arg1 $arg2 vfs_write $arg1 $arg2 This shows the 1st argument becomes NULL and multiprobes are merged to 1 probe. Link: http://lkml.kernel.org/r/158779375766.6082.201939936008972838.stgit@devnote2 Cc: Ingo Molnar Cc: stable@vger.kernel.org Fixes: 29a154810546 ("tracing: Change trace_boot to use kprobe_event interface") Reviewed-by: Tom Zanussi Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_boot.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-) diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 06d7feb5255f..9de29bb45a27 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -95,23 +95,19 @@ trace_boot_add_kprobe_event(struct xbc_node *node, const char *event) struct xbc_node *anode; char buf[MAX_BUF_LEN]; const char *val; - int ret; - - kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); - - ret = kprobe_event_gen_cmd_start(&cmd, event, NULL); - if (ret) - return ret; + int ret = 0; xbc_node_for_each_array_value(node, "probes", anode, val) { - ret = kprobe_event_add_field(&cmd, val); - if (ret) - return ret; - } + kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); - ret = kprobe_event_gen_cmd_end(&cmd); - if (ret) - pr_err("Failed to add probe: %s\n", buf); + ret = kprobe_event_gen_cmd_start(&cmd, event, val); + if (ret) + break; + + ret = kprobe_event_gen_cmd_end(&cmd); + if (ret) + pr_err("Failed to add probe: %s\n", buf); + } return ret; }