On Wed, Aug 11, 2021 at 08:45:12AM -0700, Luis Chamberlain wrote: > If you try to run tests such as generic/108 in a loop > you'll eventually see a failure, but the failure can > be a false positive and the test was just unable to remove > the scsi_debug module. > > We need to give some time for the refcnt to become 0. For > instance for the test generic/108 the refcnt lingers between > 2 and 1. It should be 0 when we're done but a bit of time > seems to be required. The chance of us trying to run rmmod > when the refcnt is 2 or 1 is low, about 1/30 times if you > run the test in a loop on linux-next today. > > Likewise, even when its 0 we just need a tiny breather before > we can remove the module (sleep 10 suffices) but this is > only required on older kernels. Otherwise removing the module > will just fail. > > Some of these races are documented on the korg#212337, and > Doug Gilbert has posted at least one patch attempt to try > to help with this [1]. The patch does not resolve all the > issues though, it helps though. > > [0] https://bugzilla.kernel.org/show_bug.cgi?id=212337 > [1] https://lkml.kernel.org/r/20210508230745.27923-1-dgilbert@xxxxxxxxxxxx > Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> > --- > common/scsi_debug | 6 ++++-- There're also some "modprobe -r" calls in common/module, should the be replaced with _patient_rmmod as well? > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/common/scsi_debug b/common/scsi_debug > index e7988469..3c9cd820 100644 > --- a/common/scsi_debug > +++ b/common/scsi_debug > @@ -4,11 +4,13 @@ > # > # Functions useful for tests on unique block devices > > +. common/module > + > _require_scsi_debug() > { > # make sure we have the module and it's not already used > modinfo scsi_debug 2>&1 > /dev/null || _notrun "scsi_debug module not found" > - lsmod | grep -wq scsi_debug && (rmmod scsi_debug || _notrun "scsi_debug module in use") > + lsmod | grep -wq scsi_debug && (_patient_rmmod scsi_debug || _notrun "scsi_debug module in use") I don't think we should use _patient_rmmod here, if we set timeout to forever and there's actually some other process using scsi_debug module, we'll loop forever here. And a failure to remove scsi_debug only results in _notrun, and won't cause false test failure. > # make sure it has the features we need > # logical/physical sectors plus unmap support all went in together > modinfo scsi_debug | grep -wq sector_size || _notrun "scsi_debug too old" > @@ -53,5 +55,5 @@ _put_scsi_debug_dev() > $UDEV_SETTLE_PROG > n=$((n-1)) > done I think the above while loop could be removed as well? Thanks, Eryu > - rmmod scsi_debug || _fail "Could not remove scsi_debug module" > + _patient_rmmod scsi_debug || _fail "Could not remove scsi_debug module" > } > -- > 2.30.2
