From: Calvin Owens <calvinowens@xxxxxx> Currently we free the resources backing the enclosure device before we call device_unregister(). This is racy: during rmmod of low-level SCSI drivers that hook into enclosure, we end up with a small window of time during which writing to /sys can OOPS. Example trace with mpt3sas: general protection fault: 0000 [#1] SMP KASAN Modules linked in: mpt3sas(-) <...> RIP: [<ffffffffa0388a98>] ses_get_page2_descriptor.isra.6+0x38/0x220 [ses] Call Trace: [<ffffffffa0389d14>] ses_set_fault+0xf4/0x400 [ses] [<ffffffffa0361069>] set_component_fault+0xa9/0xf0 [enclosure] [<ffffffff8205bffc>] dev_attr_store+0x3c/0x70 [<ffffffff81677df5>] sysfs_kf_write+0x115/0x180 [<ffffffff81675725>] kernfs_fop_write+0x275/0x3a0 [<ffffffff8151f810>] __vfs_write+0xe0/0x3e0 [<ffffffff8152281f>] vfs_write+0x13f/0x4a0 [<ffffffff81526731>] SyS_write+0x111/0x230 [<ffffffff828b401b>] entry_SYSCALL_64_fastpath+0x13/0x94 Fortunately the solution is extremely simple: call device_unregister() before we free the resources, and the race no longer exists. The driver core holds a reference over ->remove_dev(), so AFAICT this is safe. Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=989094 Signed-off-by: Calvin Owens <calvinowens@xxxxxx> Acked-by: Hannes Reinecke <hare@xxxxxxxx> --- drivers/scsi/ses.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/scsi/ses.c b/drivers/scsi/ses.c index a3f9350..ea7066c 100644 --- a/drivers/scsi/ses.c +++ b/drivers/scsi/ses.c @@ -818,8 +818,6 @@ static void ses_intf_remove_enclosure(struct scsi_device *sdev) if (!edev) return; - enclosure_unregister(edev); - ses_dev = edev->scratch; edev->scratch = NULL; @@ -831,6 +829,7 @@ static void ses_intf_remove_enclosure(struct scsi_device *sdev) kfree(edev->component[0].scratch); put_device(&edev->edev); + enclosure_unregister(edev); } static void ses_intf_remove(struct device *cdev, -- 1.8.5.6
