From: Bart Van Assche bvanassche@acm.org
[ Upstream commit 8fe4ce5836e932f5766317cb651c1ff2a4cd0506 ]
There are two .exit_cmd_priv implementations. Both implementations use resources associated with the SCSI host. Make sure that these resources are still available when .exit_cmd_priv is called by waiting inside scsi_remove_host() until the tag set has been freed.
This commit fixes the following use-after-free:
================================================================== BUG: KASAN: use-after-free in srp_exit_cmd_priv+0x27/0xd0 [ib_srp] Read of size 8 at addr ffff888100337000 by task multipathd/16727 Call Trace: <TASK> dump_stack_lvl+0x34/0x44 print_report.cold+0x5e/0x5db kasan_report+0xab/0x120 srp_exit_cmd_priv+0x27/0xd0 [ib_srp] scsi_mq_exit_request+0x4d/0x70 blk_mq_free_rqs+0x143/0x410 __blk_mq_free_map_and_rqs+0x6e/0x100 blk_mq_free_tag_set+0x2b/0x160 scsi_host_dev_release+0xf3/0x1a0 device_release+0x54/0xe0 kobject_put+0xa5/0x120 device_release+0x54/0xe0 kobject_put+0xa5/0x120 scsi_device_dev_release_usercontext+0x4c1/0x4e0 execute_in_process_context+0x23/0x90 device_release+0x54/0xe0 kobject_put+0xa5/0x120 scsi_disk_release+0x3f/0x50 device_release+0x54/0xe0 kobject_put+0xa5/0x120 disk_release+0x17f/0x1b0 device_release+0x54/0xe0 kobject_put+0xa5/0x120 dm_put_table_device+0xa3/0x160 [dm_mod] dm_put_device+0xd0/0x140 [dm_mod] free_priority_group+0xd8/0x110 [dm_multipath] free_multipath+0x94/0xe0 [dm_multipath] dm_table_destroy+0xa2/0x1e0 [dm_mod] __dm_destroy+0x196/0x350 [dm_mod] dev_remove+0x10c/0x160 [dm_mod] ctl_ioctl+0x2c2/0x590 [dm_mod] dm_ctl_ioctl+0x5/0x10 [dm_mod] __x64_sys_ioctl+0xb4/0xf0 dm_ctl_ioctl+0x5/0x10 [dm_mod] __x64_sys_ioctl+0xb4/0xf0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0
Link: https://lore.kernel.org/r/20220826002635.919423-1-bvanassche@acm.org Fixes: 65ca846a5314 ("scsi: core: Introduce {init,exit}_cmd_priv()") Cc: Ming Lei ming.lei@redhat.com Cc: Christoph Hellwig hch@lst.de Cc: Mike Christie michael.christie@oracle.com Cc: Hannes Reinecke hare@suse.de Cc: John Garry john.garry@huawei.com Cc: Li Zhijian lizhijian@fujitsu.com Reported-by: Li Zhijian lizhijian@fujitsu.com Tested-by: Li Zhijian lizhijian@fujitsu.com Signed-off-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Martin K. Petersen martin.petersen@oracle.com [mheyne: fixed contextual conflicts: - drivers/scsi/hosts.c: due to missing commit 973dac8a8a14 ("scsi: core: Refine how we set tag_set NUMA node") - drivers/scsi/scsi_sysfs.c: due to missing commit 6f8191fdf41d ("block: simplify disk shutdown") - drivers/scsi/scsi_scan.c: due to missing commit 59506abe5e34 ("scsi: core: Inline scsi_mq_alloc_queue()")] Signed-off-by: Maximilian Heyne mheyne@amazon.de Cc: stable@vger.kernel.org # v5.10 --- drivers/scsi/hosts.c | 16 +++++++++++++--- drivers/scsi/scsi_lib.c | 6 +++++- drivers/scsi/scsi_priv.h | 2 +- drivers/scsi/scsi_scan.c | 1 + drivers/scsi/scsi_sysfs.c | 1 + include/scsi/scsi_host.h | 2 ++ 6 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 297f2b412d07..17fa1cd91da6 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -182,6 +182,15 @@ void scsi_remove_host(struct Scsi_Host *shost) scsi_proc_host_rm(shost); scsi_proc_hostdir_rm(shost->hostt);
+ /* + * New SCSI devices cannot be attached anymore because of the SCSI host + * state so drop the tag set refcnt. Wait until the tag set refcnt drops + * to zero because .exit_cmd_priv implementations may need the host + * pointer. + */ + kref_put(&shost->tagset_refcnt, scsi_mq_free_tags); + wait_for_completion(&shost->tagset_freed); + spin_lock_irqsave(shost->host_lock, flags); if (scsi_host_set_state(shost, SHOST_DEL)) BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY)); @@ -240,6 +249,9 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
shost->dma_dev = dma_dev;
+ kref_init(&shost->tagset_refcnt); + init_completion(&shost->tagset_freed); + /* * Increase usage count temporarily here so that calling * scsi_autopm_put_host() will trigger runtime idle if there is @@ -312,6 +324,7 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, pm_runtime_disable(&shost->shost_gendev); pm_runtime_set_suspended(&shost->shost_gendev); pm_runtime_put_noidle(&shost->shost_gendev); + kref_put(&shost->tagset_refcnt, scsi_mq_free_tags); fail: return error; } @@ -344,9 +357,6 @@ static void scsi_host_dev_release(struct device *dev) kfree(dev_name(&shost->shost_dev)); }
- if (shost->tag_set.tags) - scsi_mq_destroy_tags(shost); - kfree(shost->shost_data);
ida_simple_remove(&host_index_ida, shost->host_no); diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 14dec86ff749..64ae7bc2de60 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1923,9 +1923,13 @@ int scsi_mq_setup_tags(struct Scsi_Host *shost) return blk_mq_alloc_tag_set(tag_set); }
-void scsi_mq_destroy_tags(struct Scsi_Host *shost) +void scsi_mq_free_tags(struct kref *kref) { + struct Scsi_Host *shost = container_of(kref, typeof(*shost), + tagset_refcnt); + blk_mq_free_tag_set(&shost->tag_set); + complete(&shost->tagset_freed); }
/** diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index 1183dbed687c..3fee9af05925 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -93,7 +93,7 @@ extern void scsi_requeue_run_queue(struct work_struct *work); extern struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev); extern void scsi_start_queue(struct scsi_device *sdev); extern int scsi_mq_setup_tags(struct Scsi_Host *shost); -extern void scsi_mq_destroy_tags(struct Scsi_Host *shost); +extern void scsi_mq_free_tags(struct kref *kref); extern void scsi_exit_queue(void); extern void scsi_evt_thread(struct work_struct *work); struct request_queue; diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 6f7c4d41c51d..e8703b043805 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -273,6 +273,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, kfree(sdev); goto out; } + kref_get(&sdev->host->tagset_refcnt); WARN_ON_ONCE(!blk_get_queue(sdev->request_queue)); sdev->request_queue->queuedata = sdev;
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 6cc4d0792e3d..bb37d698da1a 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -1481,6 +1481,7 @@ void __scsi_remove_device(struct scsi_device *sdev) mutex_unlock(&sdev->state_mutex);
blk_cleanup_queue(sdev->request_queue); + kref_put(&sdev->host->tagset_refcnt, scsi_mq_free_tags); cancel_work_sync(&sdev->requeue_work);
if (sdev->host->hostt->slave_destroy) diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 4a9f1e6e3aac..3979e946c3fd 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -548,6 +548,8 @@ struct Scsi_Host { struct scsi_host_template *hostt; struct scsi_transport_template *transportt;
+ struct kref tagset_refcnt; + struct completion tagset_freed; /* Area to keep a shared tag map */ struct blk_mq_tag_set tag_set;