Commit f32ba612 authored by Mike Christie's avatar Mike Christie Committed by Martin K. Petersen
Browse files

scsi: target: Fix crash during SPEC_I_PT handling 

__core_scsi3_add_registration clears the t10_pr_registration pr_reg_deve
and does a core_scsi3_lunacl_undepend_item which does an undepend and also
does a kref_put from the get done in __core_scsi3_alloc_registration. So
when we get to the bottom of core_scsi3_decode_spec_i_port the pr_reg_deve
is NULL and we crash when trying to access the local_pr_reg's pr_reg_deve.
We've also done an extra undepend for local_pr_reg and if we didn't crash
on the NULL we would have done an extra kref_put too.

This patch has us do a core_scsi3_lunacl_depend_item for local_pr_reg and
then let __core_scsi3_add_registration handle the cleanup for the
pr_reg_deve. We then just skip the undepend for the acl and tpg for the
local pr_reg.

The error path then works in a similar way, but we always do the
core_scsi3_lunacl_undepend_item since we never call
__core_scsi3_add_registration in that code path.

Link: https://lore.kernel.org/r/1593654203-12442-4-git-send-email-michael.christie@oracle.com


Signed-off-by: default avatarMike Christie <michael.christie@oracle.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 3c006c7d

drivers/target/target_core_pr.c

+19 −16
Original line number Diff line number Diff line
@@ -1521,13 +1521,16 @@ core_scsi3_decode_spec_i_port( 
		kfree(tidh_new);

		return TCM_INSUFFICIENT_REGISTRATION_RESOURCES;

	}



	if (core_scsi3_lunacl_depend_item(local_pr_reg->pr_reg_deve)) {

		kfree(tidh_new);

		kref_put(&local_pr_reg->pr_reg_deve->pr_kref,

			 target_pr_kref_release);

		kmem_cache_free(t10_pr_reg_cache, local_pr_reg);

		return TCM_INSUFFICIENT_REGISTRATION_RESOURCES;

	}



	tidh_new->dest_pr_reg = local_pr_reg;

	/*

	 * The local I_T nexus does not hold any configfs dependances,

	 * so we set tidh_new->dest_se_deve to NULL to prevent the

	 * configfs_undepend_item() calls in the tid_dest_list loops below.

	 */

	tidh_new->dest_se_deve = NULL;

	list_add_tail(&tidh_new->dest_list, &tid_dest_list);



	if (cmd->data_length < 28) {
@@ -1816,12 +1819,9 @@ core_scsi3_decode_spec_i_port( 
			dest_node_acl->initiatorname, i_buf, (dest_se_deve) ?

			dest_se_deve->mapped_lun : 0);



		if (!dest_se_deve) {

			kref_put(&local_pr_reg->pr_reg_deve->pr_kref,

				 target_pr_kref_release);

		if (dest_pr_reg == local_pr_reg)

			continue;

		}

		core_scsi3_lunacl_undepend_item(dest_se_deve);



		core_scsi3_nodeacl_undepend_item(dest_node_acl);

		core_scsi3_tpg_undepend_item(dest_tpg);

	}
@@ -1835,11 +1835,16 @@ out: 
	 * including *dest_pr_reg and the configfs dependances..

	 */

	list_for_each_entry_safe(tidh, tidh_tmp, &tid_dest_list, dest_list) {

		bool is_local = false;



		dest_tpg = tidh->dest_tpg;

		dest_node_acl = tidh->dest_node_acl;

		dest_se_deve = tidh->dest_se_deve;

		dest_pr_reg = tidh->dest_pr_reg;



		if (dest_pr_reg == local_pr_reg)

			is_local = true;



		list_del(&tidh->dest_list);

		kfree(tidh);

		/*
@@ -1855,13 +1860,11 @@ out: 
		}



		kmem_cache_free(t10_pr_reg_cache, dest_pr_reg);

		core_scsi3_lunacl_undepend_item(dest_se_deve);



		if (!dest_se_deve) {

			kref_put(&local_pr_reg->pr_reg_deve->pr_kref,

				 target_pr_kref_release);

		if (is_local)

			continue;

		}

		core_scsi3_lunacl_undepend_item(dest_se_deve);



		core_scsi3_nodeacl_undepend_item(dest_node_acl);

		core_scsi3_tpg_undepend_item(dest_tpg);

	}

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