On Thu, Oct 21, 2021 at 08:39:05AM +0800, Ming Lei wrote: > On Wed, Oct 20, 2021 at 08:48:04AM -0700, Luis Chamberlain wrote: > > A second series of tests is hitting CTRL-C on either randonly and > > restarting testing once again randomly. > > ltp/zram02.sh has cleanup handler via trap to clean everything(swapoff/umount/reset/ > rmmod), ctrl-c will terminate current forground task and cause shell to run the > cleanup handler first, but further 'ctrl-c' will terminate the cleanup handler, > then the cleanup won't be done completely, such as zram disk is left as swap > device and zram can't be unloaded. The idea can be observed via the following > script: > > #!/bin/bash > trap 'echo "enter trap"; sleep 20; echo "exit trap";' INT > sleep 30 > > After the above script is run foreground, when 1st ctrl-c is pressed, 'sleep 30' > is terminated, then the trap command is run, so you can see "enter trap" > dumped. Then if you pressed 2nd ctrl-c, 'sleep 20' is terminated immediately. > So 'swapoff' from zram02.sh's trap function can be terminated in this way. > > zram disk being left as swap disk can be observed with your patch too > after terminating via multiple ctrl-c which has to be done this way because > the test is dead loop. > > So it is hard to cleanup everything completely after multiple 'CTRL-C' is > involved, and it should be impossible. It needs violent multiple ctrl-c to > terminate the dealoop test. > > So it isn't reasonable to expect that zram can be always unloaded successfully > after the test script is terminated via multiple ctrl-c. For the life of me, I do not run into these issue with my patch. But with yours I had. To be clear, I run zram02.sh on two terminals. Then to interrupt I just leave CTRL-C pressed to issue multiple terminations until the script is done on each terminal at a time, until I see both have completed. I repeat the same test, noting always that when I start one one terminal the test is succeeding. And also when I cancel completely one script the test continue fine without issue. > But zram can be unloaded after running swapoff manually, from driver > viewpoint, nothing is wrong. I had not run into that issue with my patch FWIW. Luis
