From: "Steven Rostedt (Google)" <rost...@goodmis.org> If for some reason the trace_marker write does not have a nul byte for the string, it will overflow the print:
trace_seq_printf(s, ": %s", field->buf); The field->buf could be missing the nul byte. To prevent overflow, add the max size that the buf can be by using the event size and the field location. int max = iter->ent_size - offsetof(struct print_entry, buf); trace_seq_printf(s, ": %*.s", max, field->buf); Reviewed-by: Masami Hiramatsu (Google) <mhira...@kernel.org> Signed-off-by: Steven Rostedt (Google) <rost...@goodmis.org> --- Changes since v1: https://lore.kernel.org/linux-trace-kernel/20231212084444.4619b...@gandalf.local.home - Use "%.*s" and not "%*s" otherwise it right aligns the output. [ Masami, I kept your review by. ] kernel/trace/trace_output.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index d8b302d01083..3e7fa44dc2b2 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -1587,11 +1587,12 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter, { struct print_entry *field; struct trace_seq *s = &iter->seq; + int max = iter->ent_size - offsetof(struct print_entry, buf); trace_assign_type(field, iter->ent); seq_print_ip_sym(s, field->ip, flags); - trace_seq_printf(s, ": %s", field->buf); + trace_seq_printf(s, ": %.*s", max, field->buf); return trace_handle_return(s); } @@ -1600,10 +1601,11 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags, struct trace_event *event) { struct print_entry *field; + int max = iter->ent_size - offsetof(struct print_entry, buf); trace_assign_type(field, iter->ent); - trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf); + trace_seq_printf(&iter->seq, "# %lx %.*s", field->ip, max, field->buf); return trace_handle_return(&iter->seq); } -- 2.42.0
