On 12/17/20 6:27 PM, Joe Perches wrote:
> On Thu, 2020-12-17 at 18:11 +0100, Helge Deller wrote:
>> In most cases people use lookup_symbol_name() to resolve a kernel symbol
>> and then print it via printk().
>>
>> In such cases using the %ps, %pS, %pSR or %pB printk formats are easier
>> to use and thus should be preferred.
> []
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> []
>> @@ -4317,6 +4317,12 @@ sub process {
>> "LINUX_VERSION_CODE should be avoided, code should
>> be for the version to which it is merged\n" . $herecurr);
>> }
>>
>> +# avoid lookup_symbol_name()
>> + if ($line =~ /\blookup_symbol_name\b/) {
>> + WARN("PREFER_PRINTK_FORMAT",
>> + "If possible prefer %ps or %pS printk format
>> string to print symbol name instead of using lookup_symbol_name()\n" .
>> $herecurr);
>> + }
>> +
>> # check for uses of printk_ratelimit
>> if ($line =~ /\bprintk_ratelimit\s*\(/) {
>> WARN("PRINTK_RATELIMITED",
>
> Huh? nak.
>
> lookup_symbol_name is used in the kernel a grand total of 3 times.
Yes, there were much more in the past which got fixed by patches I submitted.
> 2 uses are kprobe, the other is fs/proc
Right. For fs/proc see:
https://lore.kernel.org/lkml/20201217165413.ga1...@ls3530.fritz.box/
> None of the existing uses is equivalent to %ps
Yes, those are the remaining legimate users.
> Why should this be applied?
... to prevent people to add new code with possibly unjustified use?
Helge
