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authorNicolas Pitre <nico@fluxnic.net>2020-03-28 22:25:11 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-04-29 16:33:21 +0200
commit64882aa0c531f3c372b7e5c595fabf7c42e806df (patch)
tree8d16e30b82548f73005920bddda5ce9db7a679b4
parentb027b30d1428eb5a3d117da5f6f266215836177d (diff)
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vt: don't use kmalloc() for the unicode screen buffer
commit 9a98e7a80f95378c9ee0c644705e3b5aa54745f1 upstream. Even if the actual screen size is bounded in vc_do_resize(), the unicode buffer is still a little more than twice the size of the glyph buffer and may exceed MAX_ORDER down the kmalloc() path. This can be triggered from user space. Since there is no point having a physically contiguous buffer here, let's avoid the above issue as well as reducing pressure on high order allocations by using vmalloc() instead. Signed-off-by: Nicolas Pitre <nico@fluxnic.net> Cc: <stable@vger.kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2003282214210.2671@knanqh.ubzr Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/vt/vt.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 7bb135ff555d..8b3ecef50394 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -81,6 +81,7 @@
#include <linux/errno.h>
#include <linux/kd.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <linux/major.h>
#include <linux/mm.h>
#include <linux/console.h>
@@ -350,7 +351,7 @@ static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows)
/* allocate everything in one go */
memsize = cols * rows * sizeof(char32_t);
memsize += rows * sizeof(char32_t *);
- p = kmalloc(memsize, GFP_KERNEL);
+ p = vmalloc(memsize);
if (!p)
return NULL;
@@ -366,7 +367,7 @@ static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows)
static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr)
{
- kfree(vc->vc_uni_screen);
+ vfree(vc->vc_uni_screen);
vc->vc_uni_screen = new_uniscr;
}