This is a note to let you know that I've just added the patch titled tracing: Fix event trigger to accept redundant spaces to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tracing-fix-event-trigger-to-accept-redundant-spaces.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 6784beada631800f2c5afd567e5628c843362cee Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Date: Sat, 20 Jun 2020 12:46:03 +0900 Subject: tracing: Fix event trigger to accept redundant spaces From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> 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@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Fixes: 85f2b08268c0 ("tracing: Add basic event trigger framework") Reviewed-by: Tom Zanussi <zanussi@xxxxxxxxxx> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/trace/trace_events_trigger.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -204,11 +204,17 @@ static int event_trigger_regex_open(stru 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); @@ -615,8 +621,14 @@ event_trigger_callback(struct event_comm int ret; /* separate the trigger from the filter (t:n [if filter]) */ - if (param && isdigit(param[0])) + if (param && isdigit(param[0])) { trigger = strsep(¶m, " \t"); + if (param) { + param = skip_spaces(param); + if (!*param) + param = NULL; + } + } trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); @@ -1185,6 +1197,11 @@ event_enable_trigger_func(struct event_c trigger = strsep(¶m, " \t"); if (!trigger) return -EINVAL; + if (param) { + param = skip_spaces(param); + if (!*param) + param = NULL; + } system = strsep(&trigger, ":"); if (!trigger) Patches currently in stable-queue which might be from mhiramat@xxxxxxxxxx are queue-4.4/kretprobe-prevent-triggering-kretprobe-from-within-k.patch queue-4.4/kprobes-fix-to-protect-kick_kprobe_optimizer-by-kpro.patch queue-4.4/tracing-fix-event-trigger-to-accept-redundant-spaces.patch queue-4.4/x86-kprobes-avoid-kretprobe-recursion-bug.patch