Hi,
slurm 17.11.7 does not seem to properly set X11 authority
when ~/.Xauthority is mounted via NFS.
The typical command displays :
medusa-01:/home/xxx>srun -p pshort --x11 --pty /bin/bash
xxx@node-10 ~ $ xdpyinfo
X11 connection rejected because of wrong authentication.
xdpyinfo: unable to open display "localhost:21.0".
If I add manually on node-10 the missing xauth record
xauth add node-10/unix:21 MIT-MAGIC-COOKIE-1 1234567890abcdef......
then X11 works. Looking into the code, slurmd does :
5016 setresgid(-1, 1111, -1) = 0
5016 setgroups(1, [1111]) = 0
5016 setresuid(-1, 2222, -1) = 0
5016 socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) = 11
5016 setsockopt(11, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
5016 bind(11, {sa_family=AF_INET, sin_port=htons(6088),
sin_addr=inet_addr("127.0.0.1")}, 16) = 0
5016 listen(11, 1024) = 0
5016 access("/usr/bin/xauth", R_OK|X_OK) = 0
5016 pipe([17, 18]) = 0
5016 clone(child_stack=NULL,
flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD,
child_tidptr=0x14dbccbafa50) = 5017
5016 close(18) = 0
then calls fork+execv(/usr/bin/xauth).
xauth does the following :
5017 access("/home/xxx/.Xauthority", F_OK) = 0
5017 access("/home/xxx/.Xauthority", W_OK) = -1 EACCES (Permission denied)
5017 write(2, "xauth: /home/xxx/.Xauthority not writable, changes will
be ignored\n"..., 68 <unfinished ...>
5017 <... write resumed> ) = 71
5017 umask(077 <unfinished ...>
5017 <... umask resumed> ) = 022
5017 brk(NULL) = 0x232d000
5017 brk(0x234e000) = 0x234e000
5017 open("/home/xxx/.Xauthority", O_RDONLY) = 3
5017 fstat(3, {st_mode=S_IFREG|0600, st_size=737, ...}) = 0
Unfortunately access(W_OK) fails because it uses RealUID (which is root,
mapped to nobody on NFS)
in its computations (as per man-page)
Subsequent open() succeeds because it uses EUID (non-root).
I'm not sure whether it is a bug in slurm or in xauth.
best regards,
jb
