@@ -456,8 +456,6 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
mod = sdev->host->hostt->module;
- scsi_dh_release_device(sdev);
-
parent = sdev->sdev_gendev.parent;
spin_lock_irqsave(sdev->host->host_lock, flags);
@@ -1479,6 +1477,9 @@ void __scsi_remove_device(struct scsi_device *sdev)
kref_put(&sdev->host->tagset_refcnt, scsi_mq_free_tags);
cancel_work_sync(&sdev->requeue_work);
+ /* Only detach the device handler after I/O processing has finished. */
+ scsi_dh_release_device(sdev);
+
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
The SCSI device name can be freed by kobject_cleanup() before scsi_device_dev_release_usercontext() is called since the latter function may be called asynchronously. Hence, the SCSI device name must not be dereferenced from inside the SCSI device release function. Since scsi_dh_release_device() dereferences the SCSI device name, call it earlier. This patch fixes the following use-after-free: BUG: KASAN: use-after-free in string+0xdc/0x1d0 Read of size 1 at addr ffff8881280d05f0 by task kworker/54:2/1373 CPU: 54 PID: 1373 Comm: kworker/54:2 Tainted: G E 6.0.0-rc5-dbg #12 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 Workqueue: events scsi_device_dev_release_usercontext Call Trace: <TASK> show_stack+0x4e/0x53 dump_stack_lvl+0x51/0x66 print_address_description.constprop.0.cold+0xd5/0x412 print_report.cold+0x90/0x219 kasan_report+0xb1/0xe0 __asan_load1+0x4d/0x50 string+0xdc/0x1d0 vsnprintf+0x44d/0x7f0 snprintf+0x88/0xa0 dev_vprintk_emit+0x19c/0x1dc dev_printk_emit+0x8c/0xa6 __dev_printk+0x73/0x8f _dev_printk+0xa8/0xbe sdev_prefix_printk+0x12c/0x180 scsi_dh_release_device+0x74/0xa0 scsi_device_dev_release_usercontext+0x60/0x8a0 process_one_work+0x571/0xa40 worker_thread+0x90/0x650 kthread+0x185/0x1c0 ret_from_fork+0x1f/0x30 Freed by task 509: kasan_save_stack+0x26/0x50 kasan_set_track+0x25/0x30 kasan_set_free_info+0x24/0x40 ____kasan_slab_free+0x155/0x1c0 __kasan_slab_free+0x12/0x20 kfree+0x1fe/0x3e0 kfree_const+0x21/0x30 kobject_cleanup+0x8d/0x1c0 kobject_put+0x6e/0x90 put_device+0x13/0x20 __scsi_remove_device+0x140/0x200 scsi_forget_host+0xa7/0xb0 scsi_remove_host+0x9b/0x1b0 srp_remove_work+0x12b/0x2e0 [ib_srp] process_one_work+0x571/0xa40 worker_thread+0x90/0x650 kthread+0x185/0x1c0 ret_from_fork+0x1f/0x30 Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: John Garry <john.garry@huawei.com> Cc: Mike Christie <michael.christie@oracle.com> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Fixes: 23695e41a1ca ("scsi_dh: fix use-after-free when removing scsi device") Signed-off-by: Bart Van Assche <bvanassche@acm.org> --- drivers/scsi/scsi_sysfs.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)