Re: [Valgrind-users] Invalid write of size 4 and ...

[Nicholas N. <nj...@ca...>]

On Wed, 30 Apr 2003, Xiang Yan wrote:

> 2. I have two errors in following oci call:
> ==13548== Thread 4:
> ==13548== Invalid write of size 4
> ==13548==    at 0x81FFE55: kpughndl0 (in..)
> ==13548==    by 0x82071A3: kpughndl (in ..)
> ==13548==    by 0x81DBFBA: kpubndp0 (in ..)
> ==13548==    by 0x8077F74: OCIBindByPos (in .. /* &pocibind[0,1..n-1] as a param of this call*/  )
> ==13548==    Address 0x41B6BA44 is 8 bytes after a block of size 4 alloc'd
> ==13548==    at 0x400485EC: __builtin_vec_new (vg_clientfuncs.c:156)
> ==13548==    by 0x8062AE8: myapp::prepareparams(void) (myapp.cpp:1270 /* OCIBind **pocibind = new OCIBind*[n]; */)
> ...
> Can I have more insight on "Address 0x41B6BA44 is 8 bytes after a block
> of size 4 alloc'd" ?

Your function kpughndl0() accesses the address 0x41B6BA44 which is invalid
-- not addressible.  However, it comes only 8 bytes after the end of a
valid block allocated with new[] in myapp::prepareparams(), so there's a
good chance that you've overrun the end of the block.

N