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Subject[PATCH] Fix crash in viafb due to 4k stack overflow
The function viafb_cursor() uses 2 stack-variables of CURSOR_SIZE bits;
CURSOR_SIZE is defined as (8 * 1024). Using up twice 1k on stack is too much
for 4k-stack (though it works with 8k-stacks).

Make those two variables kzalloc'ed to preserve stack space.

Signed-off-by: Bruno Prémont <bonbons@linux-vserver.org>

---
--- linux-2.6.28-rc3.orig/drviers/video/via/viafbdev.c 2008-11-09 19:22:15.000000000 +0100
+++ linux-2.6.28-rc3/drivers/video/via/viafbdev.c 2008-11-09 19:36:15.000000000 +0100
@@ -1052,10 +1052,8 @@ static void viafb_imageblit(struct fb_in

static int viafb_cursor(struct fb_info *info, struct fb_cursor *cursor)
{
- u8 data[CURSOR_SIZE / 8];
- u32 data_bak[CURSOR_SIZE / 32];
u32 temp, xx, yy, bg_col = 0, fg_col = 0;
- int size, i, j = 0;
+ int i, j = 0;
static int hw_cursor;
struct viafb_par *p_viafb_par;

@@ -1178,10 +1176,15 @@ static int viafb_cursor(struct fb_info *
}

if (cursor->set & FB_CUR_SETSHAPE) {
- size =
+ u8 *data = kzalloc(CURSOR_SIZE / 8, GFP_KERNEL);
+ u32 *data_bak = kzalloc(CURSOR_SIZE / 32, GFP_KERNEL);
+ int size =
((viacursor.image.width + 7) >> 3) *
viacursor.image.height;

+ if (data == NULL || data_bak == NULL)
+ goto out;
+
if (MAX_CURS == 32) {
for (i = 0; i < (CURSOR_SIZE / 32); i++) {
data_bak[i] = 0x0;
@@ -1231,6 +1234,9 @@ static int viafb_cursor(struct fb_info *
memcpy(((struct viafb_par *)(info->par))->fbmem_virt +
((struct viafb_par *)(info->par))->cursor_start,
data_bak, CURSOR_SIZE);
+out:
+ kfree(data);
+ kfree(data_bak);
}

if (viacursor.enable)
--
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