On 2018-11-12 15:37, Ondrej Mosnacek wrote: > On Mon, Nov 12, 2018 at 12:32 PM Ondrej Mosnacek <omosn...@redhat.com> wrote: > > On Sun, Nov 11, 2018 at 11:36 PM Richard Guy Briggs <r...@redhat.com> wrote: > > > On 2018-11-11 17:24, Ondrej Mosnacek wrote: > > > > Hi Richard, > > > > On Fri, Nov 9, 2018 at 11:04 PM Richard Guy Briggs <r...@redhat.com> > > > > wrote: > > > > > Hi Paul, Ondrej, > > > > > > > > > > I've got a couple of patches with two different approaches to address > > > > > ghak100: > > > > > https://github.com/linux-audit/audit-kernel/issues/100 > > > > > > > > > > The patches work, but I've not posted them yet because I wanted to > > > > > update the audit-testsuite first to consistently test it. > > > > > > > > > > I've written a test to automate the regression test to add to > > > > > audit-testsuite based on the reproducer recipe provided in ghak100. > > > > > The > > > > > procedure in the description of ghak100 works, but I'm having some > > > > > trouble with the script. In particular, it is hanging the script on > > > > > the > > > > > "kill 'SIGSTOP' $pid_fuse" line. Once it hangs, the main script, the > > > > > test subscript and both backgrounded processes (fuse and umount) are > > > > > still hanging around. > > > > > > > > > > Here's the script: > > > > > > > > > > https://github.com/linux-audit/audit-testsuite/compare/master...rgbriggs:ghak100-missing-mount-hang > > > > > > > > > > Do either of you have any insight why this might be happenning and how > > > > > to fix or work around it? > > > > > > > > > > A couple of minor notes: > > > > > - The $pid_fuse += 1 is necessary since it forks from the PID reported > > > > > to the shell. > > > > > > > > I don't understand... why do you expect the forked PID to be exactly > > > > one higher? This doesn't seem to be the case in general: > > > > > > > > $ (echo $$; exec bash -c 'echo $$' &) > > > > 10995 > > > > 13693 > > > > > > I was not happy with this hack, but this was the most expedient way to > > > try to get a first attempt working... I suppose a better way might be > > > to spawn the client which forks, then use something like pgrep to find > > > all the instances and eliminate the PID that was returned by the launch. > > > > How about something like: > > > > system("cd $basedir/$clientdir; mkfifo /tmp/fifo; sh -c 'echo $$ > > > /tmp/fifo; exec ./$client -f -s $tmpdir' & cat /tmp/fifo"); > > > > That should always give you the right PID. You just need to tweak it > > to create the FIFO as a temporary file and clean it up afterwards. It > > is more complicated, but should be reliable. > > > > > > > > As far as I can tell, I was hitting the right task since hitting the > > > wrong or non-existant task didn't hang the test. > > > > Yes, when I fork from a fresh shell, I also get the forked PID one > > greater practically every time, so that will be a different problem... > > I didn't look at the hang problem yet, I will try it later in the > > afternoon. > > I think I figured it out. When you send SIGTERM to the fuse process in > the cleanup section, it is still stopped, so it can't handle it. You > need to send it SIGCONT first (or kill it with SIGKILL): > [...] > ### > # cleanup > kill 'SIGCONT', $pid_fuse; > kill 'SIGTERM', $pid_umnt; > kill 'SIGTERM', $pid_fuse; > system("auditctl -D >& /dev/null"); > > With the above tweak it no longer hangs for me.
It no longer hangs, but waitpid doesn't work as expected either... I was making this overly complicated. A simple check in /proc/$pid_umnt was sufficient to see if the process was still hanging around. Thanks for looking at this. I'll update my test and post some patches... > > > > > - The SIGSTOP is necessary to simulate the hung filesystem. > > > > > > > > > > - RGB > > > > > > > > Ondrej Mosnacek <omosnace at redhat dot com> > > > > > > - RGB > > > > Ondrej Mosnacek <omosnace at redhat dot com> > > Ondrej Mosnacek <omosnace at redhat dot com> - RGB -- Richard Guy Briggs <r...@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635 -- Linux-audit mailing list Linux-audit@redhat.com https://www.redhat.com/mailman/listinfo/linux-audit