[Pvfs2-developers] double memory free problem

[Sam Lang]

Hagai,

That previous patch had a bug in it as well. :-(

The attached patch should fix your double free problem, as well as  
avoid the bug I introduced. :-)

It should be applied to the original sources.  Please let me know if  
it works for you.

Thanks,
-sam

On Oct 22, 2007, at 4:44 PM, Sam Lang wrote:

>
> Hagai,
>
> This looks like a bug when using the system interfaces directly.   
> Can you try the attached patch?
>
> Thanks,
>
> -sam
>
> <objattr-double-free.patch>
>
>
> On Oct 22, 2007, at 4:29 AM, Hagai Avrahami wrote:
>
>>
>>
>> Hi
>>
>> Maybe someone can help me with the following problem
>>
>> I have met double free problem described in valgrind log
>>
>> 1.
>> ==18442== Invalid free() / delete / delete[]
>> ==18442== at 0x401CFCF: free (vg_replace_malloc.c:235)
>> ==18442== by 0x81E983A: PINT_copy_object_attr (pint-util.c:208)
>> ==18442== by 0x81B26E5: getattr_object_getattr_comp_fn (sys- 
>> etattr.sm:535)
>> ==18442== by 0x81E8B56: msgpairarray_completion_fn  
>> (msgpairarray.sm:554)
>> ==18442== by 0x81B032B: PINT_state_machine_next (state-machine- 
>> fns.h:158)
>> ==18442== by 0x81B1196: PINT_client_state_machine_testsome
>> (client-state-machine.c:744)
>> ==18442== by 0x81B154C: PVFS_sys_testsome (client-state-machine.c: 
>> 934)
>>
>> 2.
>> ==18442==  Address 0x47421C0 is 0 bytes inside a block of size 32  
>> free'd
>> ==18442==    at 0x401CFCF: free (vg_replace_malloc.c:235)
>> ==18442==    by 0x81E9A33: PINT_free_object_attr (pint-util.c:283)
>> ==18442==    by 0x81B234B: getattr_acache_lookup (sys-getattr.sm:447)
>> ==18442==    by 0x81B032B: PINT_state_machine_next (state-machine- 
>> fns.h:158)
>> ==18442==    by 0x81B0052: PINT_client_state_machine_post
>> (client-state-machine.c:369)
>> ==18442==    by 0x81BA519: PVFS_isys_io (sys-io.sm:329)
>>
>>
>> ///////////////////////////////////////////////
>> I got this double free case after using:
>>  PVFS_isys_getattr with mask =(PVFS_ATTR_SYS_ALL_NOHINT &
>> (~PVFS_ATTR_SYS_SIZE))
>>
>> And after that, trying to read data using
>> PVFS_isys_io
>>
>> ///////////////////////////////////////////////
>>
>> After some debugging I can see that after calling free(X) there  
>> are places
>> There is assignment of X to NULL and in some cases not
>>
>> After Adding this lines to pvfs2-types.h
>>
>> #define free(x) free(x); \
>>                 x = NULL
>> The problem solved
>>
>> Do you think it's OK to Add this lines?
>>
>> Thanx for your help
>> Hagai
>>
>>
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>>
>