Re: New Defects reported by Coverity Scan for XenProject

[Jan Beulich <jbeulich@xxxxxxxx>]

On 04.09.2025 16:50, scan-admin@xxxxxxxxxxxx wrote:
> Hi,
> 
> Please find the latest report on new defect(s) introduced to XenProject found 
> with Coverity Scan.
> 
> 1 new defect(s) introduced to XenProject found with Coverity Scan.
> 2 defect(s), reported by Coverity Scan earlier, were marked fixed in the 
> recent build analyzed by Coverity Scan.
> 
> New defect(s) Reported-by: Coverity Scan
> Showing 1 of 1 defect(s)
> 
> 
> ** CID 1665214:       Integer handling issues  (INTEGER_OVERFLOW)
> /tools/firmware/xen-dir/xen-root/xen/common/symbols.c: 123           in 
> symbols_lookup()
> 
> 
> _____________________________________________________________________________________________
> *** CID 1665214:         Integer handling issues  (INTEGER_OVERFLOW)
> /tools/firmware/xen-dir/xen-root/xen/common/symbols.c: 123             in 
> symbols_lookup()
> 117         }
> 118     
> 119         /* If we hit an END symbol, move to the previous (real) one. */
> 120         if (!symbols_names[get_symbol_offset(low)]) {
> 121             ASSERT(low);

With this I wonder ...

> 122             symbol_end = symbols_address(low);
>>>>     CID 1665214:         Integer handling issues  (INTEGER_OVERFLOW)
>>>>     Expression "--low", where "low" is known to be equal to 0, underflows 
>>>> the type of "--low", which is type "unsigned int".
> 123             --low;

... how "low" can be known to be zero when getting here. Without the
assertion I would accept that the tool doesn't understand that an
"end" symbol can't come first (albeit imo the report then would still
be a false positive one).

Jan