Tested-by: Yi Zhang <yi.zhang@xxxxxxxxxx> This patch fixed one panic issue which I found on s390x with blktests srp tests. https://lore.kernel.org/linux-block/CAHj4cs8XNtkzbbiLnFmVu82wYeQpLkVp6_wCtrnbhODay+OP9w@xxxxxxxxxxxxxx/#t On Thu, Sep 30, 2021 at 8:44 PM Ming Lei <ming.lei@xxxxxxxxxx> wrote: > > SCSI host release is triggered when SCSI device is freed, and we have to > make sure that LLD module won't be unloaded before SCSI host instance is > released because shost->hostt is required in host release handler. > > So make sure to put LLD module refcnt after SCSI device is released. > > Fix one kernel panic of 'BUG: unable to handle page fault for address' > reported by Changhui and Yi. > > Reported-by: Changhui Zhong <czhong@xxxxxxxxxx> > Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > --- > drivers/scsi/scsi.c | 4 +++- > drivers/scsi/scsi_sysfs.c | 12 ++++++++++++ > include/scsi/scsi_device.h | 1 + > 3 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c > index b241f9e3885c..291ecc33b1fe 100644 > --- a/drivers/scsi/scsi.c > +++ b/drivers/scsi/scsi.c > @@ -553,8 +553,10 @@ EXPORT_SYMBOL(scsi_device_get); > */ > void scsi_device_put(struct scsi_device *sdev) > { > - module_put(sdev->host->hostt->module); > + struct module *mod = sdev->host->hostt->module; > + > put_device(&sdev->sdev_gendev); > + module_put(mod); > } > EXPORT_SYMBOL(scsi_device_put); > > diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c > index 86793259e541..9ada26814011 100644 > --- a/drivers/scsi/scsi_sysfs.c > +++ b/drivers/scsi/scsi_sysfs.c > @@ -449,9 +449,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) > struct scsi_vpd *vpd_pg80 = NULL, *vpd_pg83 = NULL; > struct scsi_vpd *vpd_pg0 = NULL, *vpd_pg89 = NULL; > unsigned long flags; > + struct module *mod; > + bool put_mod = false; > > sdev = container_of(work, struct scsi_device, ew.work); > > + if (sdev->put_lld_mod_ref) { > + mod = sdev->host->hostt->module; > + put_mod = true; > + } > + > scsi_dh_release_device(sdev); > > parent = sdev->sdev_gendev.parent; > @@ -502,11 +509,16 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) > > if (parent) > put_device(parent); > + if (put_mod) > + module_put(mod); > } > > static void scsi_device_dev_release(struct device *dev) > { > struct scsi_device *sdp = to_scsi_device(dev); > + > + sdp->put_lld_mod_ref = try_module_get(sdp->host->hostt->module); > + > execute_in_process_context(scsi_device_dev_release_usercontext, > &sdp->ew); > } > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h > index 430b73bd02ac..54b46d590e2d 100644 > --- a/include/scsi/scsi_device.h > +++ b/include/scsi/scsi_device.h > @@ -206,6 +206,7 @@ struct scsi_device { > unsigned rpm_autosuspend:1; /* Enable runtime autosuspend at device > * creation time */ > unsigned ignore_media_change:1; /* Ignore MEDIA CHANGE on resume */ > + unsigned put_lld_mod_ref:1; /* Put LLD module ref in release */ > > bool offline_already; /* Device offline message logged */ > > -- > 2.31.1 > -- Best Regards, Yi Zhang
