From: Masami Hiramatsu mhiramat@kernel.org

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 mingo@kernel.org Cc: stable@vger.kernel.org Fixes: 29a154810546 ("tracing: Change trace_boot to use kprobe_event interface") Reviewed-by: Tom Zanussi zanussi@kernel.org Signed-off-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- kernel/trace/trace_boot.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 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 @@ -95,24 +95,20 @@ 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; + int ret = 0;

- kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN); + xbc_node_for_each_array_value(node, "probes", anode, val) { + kprobe_event_cmd_init(&cmd, buf, MAX_BUF_LEN);

- ret = kprobe_event_gen_cmd_start(&cmd, event, NULL); - if (ret) - return ret; + ret = kprobe_event_gen_cmd_start(&cmd, event, val); + if (ret) + break;

- xbc_node_for_each_array_value(node, "probes", anode, val) { - ret = kprobe_event_add_field(&cmd, val); + ret = kprobe_event_gen_cmd_end(&cmd); if (ret) - return ret; + pr_err("Failed to add probe: %s\n", buf); }

- ret = kprobe_event_gen_cmd_end(&cmd); - if (ret) - pr_err("Failed to add probe: %s\n", buf); - return ret; } #else