4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Nicholas Bellinger <[email protected]> commit 391e2a6de9781e4906dd7e0b1cc097050bf43e11 upstream. After the v4.2+ RCU conversion to se_node_acl->lun_entry_hlist, a BUG_ON() was added in core_enable_device_list_for_node() to detect when the located orig->se_lun_acl contains an existing se_lun_acl pointer reference. However, this scenario can happen when a dynamically generated NodeACL is being converted to an explicit NodeACL, when the explicit NodeACL contains a different LUN mapping than the default provided by the WWN endpoint. So instead of triggering BUG_ON(), go ahead and fail instead following the original pre RCU conversion logic. Reported-by: Benjamin ESTRABAUD <[email protected]> Cc: Benjamin ESTRABAUD <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Signed-off-by: Nicholas Bellinger <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/target/target_core_device.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -351,7 +351,15 @@ int core_enable_device_list_for_node( kfree(new); return -EINVAL; } - BUG_ON(orig->se_lun_acl != NULL); + if (orig->se_lun_acl != NULL) { + pr_warn_ratelimited("Detected existing explicit" + " se_lun_acl->se_lun_group reference for %s" + " mapped_lun: %llu, failing\n", + nacl->initiatorname, mapped_lun); + mutex_unlock(&nacl->lun_entry_mutex); + kfree(new); + return -EINVAL; + } rcu_assign_pointer(new->se_lun, lun); rcu_assign_pointer(new->se_lun_acl, lun_acl);
