executing a sudo command over a "ssh -X" connection 2 times in row in background results in massive CPU usage

Bug #216891 reported by hidro on 2008-04-13
4
Affects Status Importance Assigned to Milestone
Ubuntu
Undecided
Unassigned

Bug Description

after invoking
sudo synaptic &
2 times in a row using a "ssh -X" tunnel (to localhost) results in massive CPU usage.

See comments for test case.

hidro (hidroo) wrote :
Kai Stempfle (kai-stempfle) wrote :

I was able to reproduce this behavior.
Have you tried to catch the backgrounded "sudo synaptic" by entering "fg" (without the quotes)? This should call up the hidden password-dialog and you should be able to continue working.

Kai Stempfle (kai-stempfle) wrote :

test case (requires no cached sudo-passwords):
install openssh-server
open a terminal
execute "ssh -X localhost"
login using your password
execute "sudo synaptic &"
execute "sudo synaptic &" again.

description: updated
hidro (hidroo) wrote :

"fg" restored the hidden password-dialog, but what about the cpu?

Kai Stempfle (kai-stempfle) wrote :

after entering your password synaptic should appear and you CPU usage should return to normal.

This is what happens on my machine. If you are still experiencing problems after entering your password, please tell here.

hidro (hidroo) wrote :

i don't have a problem after "fg", just asking why it acts like this. it can be a problem if a user take all the CPU for infinite.

Kai Stempfle (kai-stempfle) wrote :

Actually, moving 'sudo' to background using '&' is not an intended use of the sudo-program. if you intend to invoke programs like synaptic, please consider using gksudo instead.

After resurfacing the password prompt, sudo acts as it should do.

Thank you for taking time to report this incidence.

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