On Tue, Sep 19, 2017 at 1:27 PM, Frank Rowand <[email protected]> wrote: > On 09/10/17 03:26, Geert Uytterhoeven wrote: >> With gcc 4.1.2: >> >> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >> uninitialized in this function >> drivers/of/overlay.c:100: warning: ‘ovinfo’ 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 >> this. >> >> 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 <[email protected]> >> --- >> 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; >> >> > > I did not see this patch due to an overzealous spam filter. I noticed it > when Rob replied with his applied email. > > This check is not needed to prevent accessing overlay_name_len and ovinfo > when ov->count == 0. That is already prevented by: > > if (k >= ov->count) > goto err_free; > > because k will be zero and ov->count will be zero.
Okay, will drop. Rob
