From: Ming Lei Date: Fri, 8 Oct 2021 05:01:18 +0000 (+0800) Subject: scsi: core: Put LLD module refcnt after SCSI device is released X-Git-Tag: archive/raspbian/5.14.16-1+rpi1^2~27 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=b993b07ccc476e67cc46e3b33956cb48639be9c3;p=linux.git scsi: core: Put LLD module refcnt after SCSI device is released Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=6aa47b0134d4df6005a2385156e6fe81961dadf8 commit f2b85040acec9a928b4eb1b57a989324e8e38d3f upstream. SCSI host release is triggered when SCSI device is freed. We have to make sure that the low-level device driver module won't be unloaded before SCSI host instance is released because shost->hostt is required in the release handler. Make sure to put LLD module refcnt after SCSI device is released. Fixes a kernel panic of 'BUG: unable to handle page fault for address' reported by Changhui and Yi. Link: https://lore.kernel.org/r/20211008050118.1440686-1-ming.lei@redhat.com Cc: Greg Kroah-Hartman Reported-by: Changhui Zhong Reported-by: Yi Zhang Tested-by: Yi Zhang Signed-off-by: Ming Lei Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman Gbp-Pq: Topic bugfix/all Gbp-Pq: Name scsi-core-Put-LLD-module-refcnt-after-SCSI-device-is.patch --- diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index d26025cf5de..71dd0989c78 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 c0d31119d6d..ed05c3565e8 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -448,9 +448,12 @@ 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; sdev = container_of(work, struct scsi_device, ew.work); + mod = sdev->host->hostt->module; + scsi_dh_release_device(sdev); parent = sdev->sdev_gendev.parent; @@ -501,11 +504,17 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work) if (parent) put_device(parent); + module_put(mod); } static void scsi_device_dev_release(struct device *dev) { struct scsi_device *sdp = to_scsi_device(dev); + + /* Set module pointer as NULL in case of module unloading */ + if (!try_module_get(sdp->host->hostt->module)) + sdp->host->hostt->module = NULL; + execute_in_process_context(scsi_device_dev_release_usercontext, &sdp->ew); }