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From: Mike Christie <michael.christie@oracle.com>
To: himanshu.madhani@oracle.com, njavali@marvell.com,
	james.bottomley@hansenpartnership.com,
	linux-scsi@vger.kernel.org, target-devel@vger.kernel.org
Subject: [PATCH 2/8] target: fix cmd_count ref leak
Date: Sun, 01 Nov 2020 18:59:28 +0000
Message-ID: <1604257174-4524-3-git-send-email-michael.christie@oracle.com> (raw)
In-Reply-To: <1604257174-4524-1-git-send-email-michael.christie@oracle.com>

percpu_ref_init sets the refcount to 1 and percpu_ref_kill drops it.
Drivers like iscsi and loop do not call target_sess_cmd_list_set_waiting
during session shutdown though, so they have been calling
percpu_ref_exit
with a refcount still taken and leaking the cmd_counts memory.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
---
 drivers/target/target_core_transport.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index ff26ab0..d47619a 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -238,6 +238,14 @@ int transport_init_session(struct se_session *se_sess)
 
 void transport_uninit_session(struct se_session *se_sess)
 {
+	/*
+	 * Drivers like iscsi and loop do not call
+	 * target_sess_cmd_list_set_waiting during session shutdown so we
+	 * have to drop the ref taken at init time here.
+	 */
+	if (!se_sess->sess_tearing_down)
+		percpu_ref_put(&se_sess->cmd_count);
+
 	percpu_ref_exit(&se_sess->cmd_count);
 }
 
-- 
1.8.3.1

  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-01 18:59 [PATCH 0/8 v3] target: fix up locking/refcounting in IO paths Mike Christie
2020-11-01 18:59 ` [PATCH 1/8] target: fix lun ref count handling Mike Christie
2020-11-11  2:58   ` Martin K. Petersen
2020-11-01 18:59 ` Mike Christie [this message]
2020-11-01 18:59 ` [PATCH 3/8] qla2xxx: drop TARGET_SCF_LOOKUP_LUN_FROM_TAG Mike Christie
2020-11-01 18:59 ` [PATCH 4/8] target: remove TARGET_SCF_LOOKUP_LUN_FROM_TAG Mike Christie
2020-11-01 18:59 ` [PATCH 5/8] qla2xxx: move sess cmd list/lock to driver Mike Christie
2020-11-01 18:59 ` [PATCH 6/8] target: Drop sess_cmd_lock from IO path Mike Christie
2020-11-01 18:59 ` [PATCH 7/8] target: make state_list per cpu Mike Christie
2020-11-01 18:59 ` [PATCH 8/8] tcm loop: allow queues, can queue and cmd per lun to be settable Mike Christie
2020-11-05  3:41 ` [PATCH 0/8 v3] target: fix up locking/refcounting in IO paths Martin K. Petersen

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