[PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()

From: Geert Uytterhoeven
Date: Sun Sep 10 2017 - 06:26:17 EST

With gcc 4.1.2:

drivers/of/overlay.c: In function âdup_and_fixup_symbol_propâ:
drivers/of/overlay.c:108: warning: âoverlay_name_lenâ may be used uninitialized in this function
drivers/of/overlay.c:100: warning: âovinfoâ may be used uninitialized in this function

Indeed, if ov->count == 0, both variables are uninitialized, which may
lead to a crash when dereferencing ovinfo later.

Currently this is a false positive, as the sole creator of of_overlay
structures (of_build_overlay_info(), introduced in commit
7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for

To prevent future issues, add a check for a zero ov->count to
dup_and_fixup_symbol_prop(). Note that this does not get rid of the
actual compiler warning.

Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device tree")
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
drivers/of/overlay.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644
--- a/drivers/of/overlay.c
+++ b/drivers/of/overlay.c
@@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct of_overlay *ov,
int overlay_name_len;
int target_path_len;

- if (!prop->value)
+ if (!ov->count || !prop->value)
return NULL;
symbol_path = prop->value;