Re: [Valgrind-users] Valgrind seems to give false "Invalid read" positive with vsnprintf

[Tom H. <to...@co...>]

On 17/09/2018 10:16, Mohamed BELAOUAD wrote:

> I seem to have encountered a false positive with valgrind-3.13.0 with 
> the program below.
> https://pastebin.com/XPHsM2sF
> 
> Valgrind gives "invalid read" errors show the following pastebin: 
> https://pastebin.com/a4vzNMvW.
> 
> The error is reported during the second call to w_strdup_printf on 
> address of string a (which is created during the first call).
> If I uncomment the printf calls, the errors disappear. If I move free(a) 
> next to free(b), the errors also disappear.
> 
> I am not sure if I am missing something in my program or if those are 
> real false positives.

You have used ap twice, the second time after va_end.

I think you meant to pass ap_copy to the vsnprintf calls (and to
the va_end calls).

Tom

-- 
Tom Hughes (to...@co...)
http://compton.nu/