From: Nicolas Pitre <nico@fluxnic.net>
To: gregkh@linuxfoundation.org
Cc: Chen Wandun <chenwandun@huawei.com>,
Adam Borowski <kilobyte@angband.pl>,
jslaby@suse.com, daniel.vetter@ffwll.ch, sam@ravnborg.org,
b.zolnierkie@samsung.com, lukas@wunner.de, ghalat@redhat.com,
linux-kernel@vger.kernel.org
Subject: [PATCH] vt: don't use kmalloc() for the unicode screen buffer
Date: Sat, 28 Mar 2020 17:59:25 -0400 (EDT) [thread overview]
Message-ID: <nycvar.YSQ.7.76.2003281745280.2671@knanqh.ubzr> (raw)
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>
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 15d2769805..7c10edb648 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -350,7 +350,7 @@ 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 +366,7 @@ 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;
}
next reply other threads:[~2020-03-28 21:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-28 21:59 Nicolas Pitre [this message]
2020-03-28 23:35 ` [PATCH] vt: don't use kmalloc() for the unicode screen buffer kbuild test robot
2020-03-29 0:13 ` kbuild test robot
2020-03-29 2:25 ` [PATCH v2] " Nicolas Pitre
2020-03-30 19:07 ` Sam Ravnborg
2020-03-31 8:43 ` Daniel Vetter
2020-03-31 9:30 ` Greg KH
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