ngx_http_variable_unknown_header() derefances null pointer

[Maxim Dounin]

Hello!

On Sat, Sep 04, 2010 at 12:06:45AM +0400, Franchoze Eric wrote:

> Got segfault at src/http/ngx_http_upstream.c:3905
> 
> 0.8.49
> built by gcc 4.1.2 20080704 (Red Hat 4.1.2-48)

[...]

> [New process 6511]
> #0  ngx_http_upstream_header_variable (r=0x816aab0, v=0x0, data=12618048)
>     at src/http/ngx_http_upstream.c:3905
> 3905	    return ngx_http_variable_unknown_header(v, (ngx_str_t *) data,
> (gdb) bt
> #0  ngx_http_upstream_header_variable (r=0x816aab0, v=0x0, data=12618048)
>     at src/http/ngx_http_upstream.c:3905
> #1  0x000000000816aab0 in ?? ()
> #2  0x0000000000afa068 in ?? ()
> #3  0x0000000000436a92 in ngx_http_upstream_check_broken_connection (r=0x1f3, ev=0x816aab0)
>     at src/http/ngx_http_upstream.c:1026
> #4  0x0000000000436b17 in ngx_http_upstream_check_broken_connection (r=0x5, ev=0x0)
>     at src/http/ngx_http_upstream.c:1048
> #5  0x0000000000464609 in ngx_http_memc_process_simple_header (r=0x816aab0)
>     at src/ngx_http_memc_response.c:3230

Looks like the problem is caused by memc module.  You may want to 
cc it's author.

Maxim Dounin