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SubjectRe: [PATCH] objtool: check: Fix NULL pointer dereference
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On 3/31/20 17:04, Josh Poimboeuf wrote:
> On Mon, Mar 30, 2020 at 07:20:40PM -0500, Gustavo A. R. Silva wrote:
>> In case func is null, there is a null pointer dereference at 2029:
>>
>> 2029 WARN("%s uses BP as a scratch register",
>> 2030 func->name);
>>
>> Fix this by null-checking func.
>>
>> Addresses-Coverity-ID: 1492002 ("Dereference after null check")
>> Fixes: c705cecc8431 ("objtool: Track original function across branches")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> tools/objtool/check.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
>> index e3bb76358148..182cc48fa892 100644
>> --- a/tools/objtool/check.c
>> +++ b/tools/objtool/check.c
>> @@ -2025,7 +2025,7 @@ static int validate_return(struct symbol *func, struct instruction *insn, struct
>> return 1;
>> }
>>
>> - if (state->bp_scratch) {
>> + if (func && state->bp_scratch) {
>> WARN("%s uses BP as a scratch register",
>> func->name);
>> return 1;
>
> We should still do the warning even if there's no func. I'll make a
> slightly different patch which unconditionally uses WARN_FUNC().
>

Awesome. :)

> I'll give you Reported-by credit and keep the coverity tag. Thanks!
>

Great.

Thanks
--
Gustavo

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