[libunwind] bug in get_list_addr()

[Todd L Miller]

        In get_list_addr() (ptrace/_UPT_get_dyn_info_list_addr.c),
libunwind appears to assume that /proc/*/maps contains only filenames or
empty strings in its last column.  However, if a shared memory segment has
been established in the remote process, this entry contains strings like
"/SYSV00001b58", sometimes with a trailing "(deleted)".  These strings, of
course, can't be mapped by elf_map_image(); however, get_list_addr()
returns -UNW_ENOINFO when this mapping fails, even if it has previously
located a dynamic unwind informat list address.  Looking at the code, I
can't find any reason for it not so simply continue;, and patching it to
do so seems to solve the problem.  (On or around line 62.)  Let me know if
you need any more information to (commit a) fix (for) this.  Thanks.

- Todd L Miller