Re: [PATCH v4 2/8] scripts/kallsyms: ensure that all possible combinations are compressed

Leizhen (ThunderTown)
2022-09-21T08:31:26Z

On 2022/9/21 16:00, Petr Mladek wrote:
> On Tue 2022-09-20 15:13:11, Zhen Lei wrote:
>> For a symbol, there may be more than one place that can be merged. For
>> example: nfs_fs_proc_net_init, there are two "f"+"s_" combinations.
>> And we're only compressing the first combination at the moment.
>
> Really?

Yes, there are about 200 such functions.

>
>> diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
>> index 8caccc8f4a23703..3319d9f38d7a5f2 100644
>> --- a/scripts/kallsyms.c
>> +++ b/scripts/kallsyms.c
>> @@ -553,7 +553,7 @@ static void compress_symbols(const unsigned char *str, int idx)
>> unsigned char *p1, *p2;
>>
>> for (i = 0; i < table_cnt; i++) {
>> -
>> +retry:
>> len = table[i]->len;
>> p1 = table[i]->sym;
>>
>> @@ -585,6 +585,9 @@ static void compress_symbols(const unsigned char *str, int idx)
>>
>> /* increase the counts for this symbol's new tokens */
>> learn_symbol(table[i]->sym, len);
>> +
>> + /* May be more than one place that can be merged, try again */
>> + goto retry;
>> }
>> }
>
> My understanding is that the code already tries to find the same
> token several times. Here are the important parts of the existing
> code:
>
> static void compress_symbols(const unsigned char *str, int idx)
> {
>
> p2 = find_token(p1, len, str);
>
> do {
> /* replace the found token with idx */
> *p2 = idx;
> [...]
>
> /* find the token on the symbol */
> p2 = find_token(p1, size, str);

Oh, yes, it retries. Let me reanalyze it. However, the problem is
real, and there may be a problem somewhere in the loop.

>
> } while (p2);
>
> Best Regards,
> Petr
> .
>

--
Regards,
Zhen Lei