[PATCH] libdwfl: fix crash when reading link map

[Omar Sandoval]

On Wed, Jun 09, 2021 at 05:45:57PM -0700, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> When read_addrs() was converted was converted from a nested function to
> a normal function, there was a mistake in converting "buffer" from a
> closure variable to a parameter: we are checking whether the pointer
> argument is NULL, not whether the buffer itself is NULL. This causes a
> NULL pointer dereference when we try to use the NULL buffer later.
> 
> Fixes: 3bf41d458fb6 ("link_map: Pull read_addrs() into file scope") made
                                                                      ^^^^
Stray word here, hopefully not too much trouble to fix up when applying.