[PATCH 5.4 127/165] s390/dasd: fix memleak in path handling error case

Greg Kroah-Hartman
2020-01-11T10:31:15Z

From: Stefan Haberland <sth@linux.ibm.com>

[ Upstream commit 00b39f698a4f1ee897227cace2e3937fc4412270 ]

If for whatever reason the dasd_eckd_check_characteristics() function
exits after at least some paths have their configuration data
allocated those data is never freed again. In the error case the
device->private pointer is set to NULL and dasd_eckd_uncheck_device()
will exit without freeing the path data because of this NULL pointer.

Fix by calling dasd_eckd_clear_conf_data() for error cases.

Also use dasd_eckd_clear_conf_data() in dasd_eckd_uncheck_device()
to avoid code duplication.

Reported-by: Qian Cai <cai@lca.pw>
Reviewed-by: Jan Hoeppner <hoeppner@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/block/dasd_eckd.c | 19 ++-----------------
1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index f5622f4a2ecf..a28b9ff82378 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2074,7 +2074,7 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
dasd_free_block(device->block);
device->block = NULL;
out_err1:
- kfree(private->conf_data);
+ dasd_eckd_clear_conf_data(device);
kfree(device->private);
device->private = NULL;
return rc;
@@ -2083,7 +2083,6 @@ dasd_eckd_check_characteristics(struct dasd_device *device)
static void dasd_eckd_uncheck_device(struct dasd_device *device)
{
struct dasd_eckd_private *private = device->private;
- int i;

if (!private)
return;
@@ -2093,21 +2092,7 @@ static void dasd_eckd_uncheck_device(struct dasd_device *device)
private->sneq = NULL;
private->vdsneq = NULL;
private->gneq = NULL;
- private->conf_len = 0;
- for (i = 0; i < 8; i++) {
- kfree(device->path[i].conf_data);
- if ((__u8 *)device->path[i].conf_data ==
- private->conf_data) {
- private->conf_data = NULL;
- private->conf_len = 0;
- }
- device->path[i].conf_data = NULL;
- device->path[i].cssid = 0;
- device->path[i].ssid = 0;
- device->path[i].chpid = 0;
- }
- kfree(private->conf_data);
- private->conf_data = NULL;
+ dasd_eckd_clear_conf_data(device);
}

static struct dasd_ccw_req *
--
2.20.1