From: Yun Zhou <yun.zhou@xxxxxxxxxxxxx> commit 6a2cbc58d6c9d90cd74288cc497c2b45815bc064 upstream. Since the raw memory 'data' does not go forward, it will dump repeated data if the data length is more than 8. If we want to dump longer data blocks, we need to repeatedly call macro SEQ_PUT_HEX_FIELD. I think it is a bit redundant, and multiple function calls also affect the performance. Link: https://lore.kernel.org/lkml/20210625122453.5e2fe304@xxxxxxxxxxxxxxxx/ Link: https://lkml.kernel.org/r/20210626032156.47889-2-yun.zhou@xxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Fixes: 6d2289f3faa7 ("tracing: Make trace_seq_putmem_hex() more robust") Signed-off-by: Yun Zhou <yun.zhou@xxxxxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- lib/seq_buf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/lib/seq_buf.c +++ b/lib/seq_buf.c @@ -243,12 +243,14 @@ int seq_buf_putmem_hex(struct seq_buf *s break; /* j increments twice per loop */ - len -= j / 2; hex[j++] = ' '; seq_buf_putmem(s, hex, j); if (seq_buf_has_overflowed(s)) return -1; + + len -= start_len; + data += start_len; } return 0; }
