RFR: 8062672: JVM crashes during GC on various asserts which checks that HeapWord ptr is an oop

[Stefan Johansson]

Thanks for looking at this Jon,

On 2014-12-05 23:30, Jon Masamitsu wrote:
> Stefan,
>
> Changes look good.
>
> Would you like to explicitly check the return from
> fgets() against NULL?  Your call.
>
I see that all other while(fgets...) checks for != NULL so I will add it.
> What do you think of an assert after the call to fgets() to
> check the length of the returned string.
>
> assert(strnlen(line, 1023) < 1023, "buffer line[1024] is too small.");
>
> Too paranoid?
I like adding an assert, but using strnlen feels a little paranoid since 
fgets promise to add '\0' at the end even if the line is longer than the 
buffer. So I plan to add this assert:
assert(strlen(line) < sizeof(line) - 1, "buffer line[1024] is too small.");

Thanks,
Stefan
>
> Reviewed.
>
> Jon
>
> On 12/5/2014 2:01 AM, Stefan Johansson wrote:
>> Hi,
>>
>> Please review this fix for the linux-sparc issue described in:
>> https://bugs.openjdk.java.net/browse/JDK-8062672
>>
>> Webrev:
>> http://cr.openjdk.java.net/~sjohanss/8062672/hotspot.00/
>>
>> Summary:
>> This fix is based on 7u-dev because the most linux-sparc testing is 
>> done for that release and also because it's unclear if we have time 
>> to move the fix the normal way through 9 and 8u before going into 7u. 
>> But the main reason is that it would be good to get testing of the 
>> fix in 7u before porting it to 8u and 9.
>>
>> The fix it self is fairly simple, after JDK-8029190 was backported 
>> the condition for disabling UseMemSetInBOT changed from is_niagara() 
>> to has_blk_init(). This worked well for solaris-sparc but on 
>> linux-sparc we previously only set the niagara feature bits, so this 
>> change adds support for detecting blk_init support on linux-sparc.
>>
>> Testing:
>> Crashes/asserts was reproducible without the fix and after the fix 
>> none have been observed. Also verified that UseMemSetInBOT now is set 
>> to false as it should be.
>>
>> Thanks,
>> Stefan
>