Re: [PATCH] tty: vt: consolemap: Add missing kfree() in con_do_clear_unimap()

From: Jiri Slaby
Date: Mon Apr 25 2022 - 03:00:24 EST


On 09. 03. 22, 13:34, 聂江磊 wrote:
I found this bug by using clang static analyse checkers. I found that function con_release_unimap() is only called in this file(drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c). There are totally 5 times that con_release_unimap() is called
(line 430, 466, 522, 599, 673) while con_release_unimap() is not followed by kfree() only in line 522. So I think it is a bug
and make this patch.

At 2022-03-03 10:06:30, "Jianglei Nie" <niejianglei2021@xxxxxxx> wrote:
We should free p after con_release_unimap(p) like the call points of
con_release_unimap() do in the same file.

But this one does not free it on purpose, right? See below.

This patch adds the missing kfree() after con_release_unimap(p).

Signed-off-by: Jianglei Nie <niejianglei2021@xxxxxxx>
drivers/tty/vt/consolemap.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index d815ac98b39e..5279c3d27720 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -520,6 +520,7 @@ static int con_do_clear_unimap(struct vc_data *vc)
p->sum = 0;
+ kfree(p);

You've just broken con_set_unimap(), or do I miss something?

return 0;

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