Syscall param write(buf) contains uninitialised or unaddressable byte(s)
   at 0x........: __libc_write (...libc...)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: (within /.../tests/fwrite)
   Address 0x........ is 0 bytes inside a block of size 10 alloc'd
   at 0x........: malloc (vg_clientfuncs.c:...)
   by 0x........: main (fwrite.c:6)
   by 0x........: __libc_start_main (...libc...)
   by 0x........: (within /.../tests/fwrite)

ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
malloc/free: in use at exit: 10 bytes in 1 blocks.
malloc/free: 1 allocs, 0 frees, 10 bytes allocated.
For a detailed leak analysis,  rerun with: --leak-check=yes
For counts of detected errors, rerun with: -v