src/os/unix/ngx_files.c:362: error: Null Dereference
  pointer `iov` last assigned on line 353 could be null and is dereferenced at line 362, column 13.

src/os/unix/ngx_files.c:345:1: start of procedure ngx_chain_to_iovec()
343. 
344. 
345. static ngx_chain_t *
     ^
346. ngx_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *cl)
347. {

src/os/unix/ngx_files.c:353:5: 
351.     struct iovec  *iov;
352. 
353.     iov = NULL;
         ^
354.     prev = NULL;
355.     total = 0;

src/os/unix/ngx_files.c:354:5: 
352. 
353.     iov = NULL;
354.     prev = NULL;
         ^
355.     total = 0;
356.     n = 0;

src/os/unix/ngx_files.c:355:5: 
353.     iov = NULL;
354.     prev = NULL;
355.     total = 0;
         ^
356.     n = 0;
357. 

src/os/unix/ngx_files.c:356:5: 
354.     prev = NULL;
355.     total = 0;
356.     n = 0;
         ^
357. 
358.     for ( /* void */ ; cl; cl = cl->next) {

src/os/unix/ngx_files.c:358:24: Loop condition is true. Entering loop body
356.     n = 0;
357. 
358.     for ( /* void */ ; cl; cl = cl->next) {
                            ^
359.         size = cl->buf->last - cl->buf->pos;
360. 

src/os/unix/ngx_files.c:359:9: 
357. 
358.     for ( /* void */ ; cl; cl = cl->next) {
359.         size = cl->buf->last - cl->buf->pos;
             ^
360. 
361.         if (prev == cl->buf->pos) {

src/os/unix/ngx_files.c:361:13: Taking true branch
359.         size = cl->buf->last - cl->buf->pos;
360. 
361.         if (prev == cl->buf->pos) {
                 ^
362.             iov->iov_len += size;
363. 

src/os/unix/ngx_files.c:362:13: 
360. 
361.         if (prev == cl->buf->pos) {
362.             iov->iov_len += size;
                 ^
363. 
364.         } else {
