This happened to me because I had enabled an alternative authentication mechanism in PAM (fingerprint reader). As soon as I disabled that, gksu started working again. The lines in /etc/pam.d/common-auth look(ed) like this:
auth sufficient pam_bioapi.so {<snip>} /etc/bioapi/pam/ password sufficient pam_bioapi.so {<snip>} /etc/bioapi/pam/ This works fine for GDM; as soon as I enter my username at the initial login screen, I get a prompt to swipe my finger. gksu never shows anything, however. It just hangs there indefinitely. strace output is (over and over): nanosleep({0, 1000000}, NULL) = 0 read(15, 0xb7fa2000, 1024) = -1 EAGAIN (Resource temporarily unavailable) waitpid(13318, 0xbfaca18c, WNOHANG) = 0 stat64("/proc/13318", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0 open("/proc/13318/stat", O_RDONLY) = 16 read(16, "13318 (sudo) S 13317 13318 13318"..., 8191) = 189 close(16) = 0 -- gksu doesn't always pop up a dialog https://bugs.launchpad.net/bugs/91151 You received this bug notification because you are a member of Ubuntu Bugs, which is the bug contact for Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs