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tracing: Fix event trigger to accept redundant spaces 

commit 6784beada631800f2c5afd567e5628c843362cee upstream.

Fix the event trigger to accept redundant spaces in
the trigger input.

For example, these return -EINVAL

echo " traceon" > events/ftrace/print/trigger
echo "traceon  if common_pid == 0" > events/ftrace/print/trigger
echo "disable_event:kmem:kmalloc " > events/ftrace/print/trigger

But these are hard to find what is wrong.

To fix this issue, use skip_spaces() to remove spaces
in front of actual tokens, and set NULL if there is no
token.

Link: http://lkml.kernel.org/r/159262476352.185015.5261566783045364186.stgit@devnote2

Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 85f2b08268 ("tracing: Add basic event trigger framework")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Masami Hiramatsu 2020-06-20 12:46:03 +09:00 committed by Sasha Levin
parent c036eb65fd
commit 9a59a88b3d
1 changed files with 19 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
kernel/trace/trace_events_trigger.c
View File

@ -216,11 +216,17 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file)
static int trigger_process_regex(struct trace_event_file *file, char *buff)
{
char *command, *next = buff;
char *command, *next;
struct event_command *p;
int ret = -EINVAL;
next = buff = skip_spaces(buff);
command = strsep(&next, ": \t");
if (next) {
next = skip_spaces(next);
if (!*next)
next = NULL;
}
command = (command[0] != '!') ? command : command + 1;
mutex_lock(&trigger_cmd_mutex);
@ -630,8 +636,14 @@ event_trigger_callback(struct event_command *cmd_ops,
int ret;
/* separate the trigger from the filter (t:n [if filter]) */
if (param && isdigit(param[0]))
if (param && isdigit(param[0])) {
trigger = strsep(&param, " \t");
if (param) {
param = skip_spaces(param);
if (!*param)
param = NULL;
}
}
trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger);
@ -1368,6 +1380,11 @@ int event_enable_trigger_func(struct event_command *cmd_ops,
trigger = strsep(&param, " \t");
if (!trigger)
return -EINVAL;
if (param) {
param = skip_spaces(param);
if (!*param)
param = NULL;
}
system = strsep(&trigger, ":");
if (!trigger)