RFR: 8230466: check malloc/calloc results in jdk.hotspot.agent

[Yasumasa Suenaga]

Hi Matthias,

src/jdk.hotspot.agent/linux/native/libsaproc/symtab.c:
```
  405       // guarantee(symtab == NULL, "multiple symtab");
  406       symtab = (struct symtab*)calloc(1, sizeof(struct symtab));
  407       if (symtab == NULL) {
  408          goto quit;
  409       }
  410       memset(symtab, 0, sizeof(struct symtab));
```

Why do you call memset() to clear symtab in L410?
symtab is allocated via calloc() in L406, so symtab would already cleared.


Thanks,

Yasumasa (ysuenaga)


On 2019/09/03 18:14, David Holmes wrote:
> Hi Matthias,
> 
> Re-directing to serviceability-dev.
> 
> David
> 
> On 3/09/2019 5:42 pm, Baesken, Matthias wrote:
>> Hello, please review the following small fix .
>>
>> In   jdk.hotspot.agent  native code (linux / macosx)   we miss to check the  result of malloc/calloc a few times .
>> This should be  adjusted.
>> Additionally  I added initialization  to the symtab  array  in  symtab.c   (by calling memset  to make sure we have a defined state )  .
>>
>>
>>
>> One question (was not really sure about this one so I did not change it so far) :
>>
>> http://cr.openjdk.java.net/~mbaesken/webrevs/8230466.0/src/jdk.hotspot.agent/macosx/native/libsaproc/symtab.c.frames.html
>>
>> 359 void destroy_symtab(symtab_t* symtab) {
>> 360   if (!symtab) return;
>> 361   free(symtab->strs);
>> 362   free(symtab->symbols);
>> 363   free(symtab);
>> 364 }
>>
>>
>>
>> Here we miss to close   symtab->hash_table   (opened by  dbopen) ,  is it needed  (haven't  used dbopen much - maybe someone can comment on this)?
>>
>>
>> bug/webrev :
>>
>> https://bugs.openjdk.java.net/browse/JDK-8230466
>>
>> http://cr.openjdk.java.net/~mbaesken/webrevs/8230466.0/
>>
>>
>> Thanks and best regards, Matthias
>>