Syscall param write(buf) points to uninitialised byte(s)
   ...
   by 0x........: main (fwrite.c:12)
 Address 0x........ is 0 bytes inside a block of size 10 alloc'd
   at 0x........: malloc (vg_replace_malloc.c:...)
   by 0x........: main (fwrite.c:7)