On Sun, 25 Oct 2026 17:38:22 +0900 "Masami Hiramatsu (Google)" <[email protected]> wrote:
> From: Masami Hiramatsu (Google) <[email protected]> > > Each trace event or subsystem only holds a single filter, and > append_filter_err() / tracing_log_err() caret placement assumes a > single-line filter string. However, apply_event_filter() and > apply_subsystem_event_filter() only call strstrip(), which strips > trailing newlines but leaves embedded newlines intact. > > An embedded newline in a filter string (for example inside 'CPUS{0\n"}') > causes cpulist_parse() / bitmap_parselist() to treat '\n' as the end of > the cpulist and ignore trailing characters before '}', desynchronizing > quote tracking between calc_stack() and parse_pred() and misaligning > error_log caret reporting. > > Terminate filter_string at the first '\n' in apply_event_filter(), > apply_subsystem_event_filter(), and create_filter_start() so only the > first line is parsed. How about also checking if there's any non white space after the newline, and if so, fail the filter outright with -EINVAL? -- Steve > > Signed-off-by: Masami Hiramatsu (Google) <[email protected]> > --- > kernel/trace/trace_events_filter.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/kernel/trace/trace_events_filter.c > b/kernel/trace/trace_events_filter.c > index 8d7fb6e9d7f8..14afcca7a444 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -2426,10 +2426,15 @@ static int create_filter_start(char *filter_string, > bool set_str, > struct event_filter *filter; > struct filter_parse_error *pe = NULL; > int err = 0; > + char *p; > > if (WARN_ON_ONCE(*pse || *filterp)) > return -EINVAL; > > + p = strchr(filter_string, '\n'); > + if (p) > + *p = '\0'; > + > filter = kzalloc_obj(*filter); > if (filter && set_str) { > filter->filter_string = kstrdup(filter_string, GFP_KERNEL); > @@ -2543,11 +2548,16 @@ int apply_event_filter(struct trace_event_file *file, > char *filter_string) > { > struct trace_event_call *call = file->event_call; > struct event_filter *filter = NULL; > + char *p; > int err; > > if (file->flags & EVENT_FILE_FL_FREED) > return -ENODEV; > > + p = strchr(filter_string, '\n'); > + if (p) > + *p = '\0'; > + > if (!strcmp(strstrip(filter_string), "0")) { > filter_disable(file); > filter = event_filter(file); > @@ -2595,6 +2605,7 @@ int apply_subsystem_event_filter(struct > trace_subsystem_dir *dir, > struct trace_array *tr = dir->tr; > struct event_filter *filter = NULL; > int err = 0; > + char *p; > > guard(mutex)(&event_mutex); > > @@ -2602,6 +2613,10 @@ int apply_subsystem_event_filter(struct > trace_subsystem_dir *dir, > if (!dir->nr_events) > return -ENODEV; > > + p = strchr(filter_string, '\n'); > + if (p) > + *p = '\0'; > + > if (!strcmp(strstrip(filter_string), "0")) { > filter_free_subsystem_preds(dir, tr); > remove_filter_string(system->filter);
