Re: [PATCH-next] x86/kernel: Fix unchecked return value

[Colin Ian King <colin.king@canonical.com>]

On 15/05/2021 21:36, Borislav Petkov wrote:
> On Sat, May 15, 2021 at 09:22:12PM +0100, Khaled ROMDHANI wrote:
>> From the coverity scan analysis, the return value from
>> insn_decode_kernel is not checked. It is a macro constructed
>> from the insn_decode function which may fail and return
>> negative integer. Fix this by explicitly checking the
>> return value.
>>
>> Addresses-Coverity: ("Unchecked return value")
>> Signed-off-by: Khaled ROMDHANI <khaledromdhani216@gmail.com>
>> ---
>>  arch/x86/kernel/jump_label.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/jump_label.c b/arch/x86/kernel/jump_label.c
>> index a762dc1c615e..bf0ea003b6e7 100644
>> --- a/arch/x86/kernel/jump_label.c
>> +++ b/arch/x86/kernel/jump_label.c
>> @@ -23,7 +23,7 @@ int arch_jump_entry_size(struct jump_entry *entry)
>>  {
>>  	struct insn insn = {};
>>  
>> -	insn_decode_kernel(&insn, (void *)jump_entry_code(entry));
>> +	WARN_ON(insn_decode_kernel(&insn, (void *)jump_entry_code(entry)));
> 
> I don't think coverity is smart enough to notice...
> 
>>  	BUG_ON(insn.length != 2 && insn.length != 5);
> 	^^^^^^^^^^^^^
> 
> ... this line.
> 
> 
Indeed. One needs to be careful with false positives with Coverity.

Colin