linux-kernel - [PATCH -next] scsi: scsi_dh_alua: fix memleak for 'qdata' in alua

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Message-Id: <20230315062154.668812-1-yukuai1@huaweicloud.com>
Date:   Wed, 15 Mar 2023 14:21:54 +0800
From:   Yu Kuai <yukuai1@...weicloud.com>
To:     jejb@...ux.ibm.com, martin.petersen@...cle.com, bvanassche@....org,
        hare@...e.de, axboe@...nel.dk, sconnor@...estorage.com,
        michael.christie@...cle.com, brian@...estorage.com,
        yukuai3@...wei.com
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai1@...weicloud.com, yi.zhang@...wei.com, yangerkun@...wei.com
Subject: [PATCH -next] scsi: scsi_dh_alua: fix memleak for 'qdata' in alua_activate()

From: Yu Kuai <yukuai3@...wei.com>

If alua_rtpg_queue() failed from alua_activate(), then 'qdata' is not
freed, which will cause following memleak:

unreferenced object 0xffff88810b2c6980 (size 32):
  comm "kworker/u16:2", pid 635322, jiffies 4355801099 (age 1216426.076s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    40 39 24 c1 ff ff ff ff 00 f8 ea 0a 81 88 ff ff  @9$.............
  backtrace:
    [<0000000098f3a26d>] alua_activate+0xb0/0x320
    [<000000003b529641>] scsi_dh_activate+0xb2/0x140
    [<000000007b296db3>] activate_path_work+0xc6/0xe0 [dm_multipath]
    [<000000007adc9ace>] process_one_work+0x3c5/0x730
    [<00000000c457a985>] worker_thread+0x93/0x650
    [<00000000cb80e628>] kthread+0x1ba/0x210
    [<00000000a1e61077>] ret_from_fork+0x22/0x30

Fix the problem by freeing 'qdata' in error path.

Fixes: 625fe857e4fa ("scsi: scsi_dh_alua: Check scsi_device_get() return value")
Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 drivers/scsi/device_handler/scsi_dh_alua.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
index 362fa631f39b..a226dc1b65d7 100644
--- a/drivers/scsi/device_handler/scsi_dh_alua.c
+++ b/drivers/scsi/device_handler/scsi_dh_alua.c
@@ -1145,10 +1145,12 @@ static int alua_activate(struct scsi_device *sdev,
 	rcu_read_unlock();
 	mutex_unlock(&h->init_mutex);
 
-	if (alua_rtpg_queue(pg, sdev, qdata, true))
+	if (alua_rtpg_queue(pg, sdev, qdata, true)) {
 		fn = NULL;
-	else
+	} else {
+		kfree(qdata);
 		err = SCSI_DH_DEV_OFFLINED;
+	}
 	kref_put(&pg->kref, release_port_group);
 out:
 	if (fn)
-- 
2.31.1