Re: [PATCH] char: tty3270: fix a missing check on list iterator

On Mon, 28 Mar 2022 08:01:02 +0200, Sven Schnelle wrote:

...

diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c index 5c83f71c1d0e..030e9a098d11 100644 --- a/drivers/s390/char/tty3270.c +++ b/drivers/s390/char/tty3270.c @@ -1111,7 +1111,7 @@ tty3270_convert_line(struct tty3270 *tp, int line_nr) { struct tty3270_line *line; struct tty3270_cell *cell;

• struct string *s, *n;

• struct string *s = NULL, *n, *iter; unsigned char highlight; unsigned char f_color; char *cp;

@@ -1142,13 +1142,15 @@ tty3270_convert_line(struct tty3270 *tp, int line_nr) /* Find the line in the list. */ i = tp->view.rows - 2 - line_nr;

• list_for_each_entry_reverse(s, &tp->lines, list)

• if (--i <= 0)
  

• list_for_each_entry_reverse(iter, &tp->lines, list)

• if (--i <= 0) {
  

• 	s = iter;
  break;
  

• }
  

  /*
  • Check if the line needs to get reallocated.
  */

• if (s->len != flen) {

• if (!s || s->len != flen) {

This doesn't look right. You're checking for s == NULL here

...

/* Reallocate string. */
n = tty3270_alloc_string(tp, flen);
list_add(&n->list, &s->list);

and if it is NULL, list_add() would be called here.

Yes, you are right, i have submitted PATCH v2 to fix it, thank you.

-- Xiaomeng Tong