* [PATCH] [media] Siano: Use common error handling code in smsusb_init_device()
@ 2017-09-20 12:40 SF Markus Elfring
2017-09-20 13:56 ` Dan Carpenter
0 siblings, 1 reply; 3+ messages in thread
From: SF Markus Elfring @ 2017-09-20 12:40 UTC (permalink / raw)
To: linux-media, Mauro Carvalho Chehab; +Cc: LKML, kernel-janitors
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Wed, 20 Sep 2017 14:30:55 +0200
Add a jump target so that a bit of exception handling can be better
reused at the end of this function.
This refactoring might fix also an error situation where the
function "kfree" was not called after a software failure
was noticed in two cases.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
drivers/media/usb/siano/smsusb.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/media/usb/siano/smsusb.c b/drivers/media/usb/siano/smsusb.c
index 8c1f926567ec..b8e7b05cf6d0 100644
--- a/drivers/media/usb/siano/smsusb.c
+++ b/drivers/media/usb/siano/smsusb.c
@@ -458,12 +458,10 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
rc = smscore_register_device(¶ms, &dev->coredev, mdev);
if (rc < 0) {
pr_err("smscore_register_device(...) failed, rc %d\n", rc);
- smsusb_term_device(intf);
#ifdef CONFIG_MEDIA_CONTROLLER_DVB
media_device_unregister(mdev);
#endif
- kfree(mdev);
- return rc;
+ goto terminate_device;
}
smscore_set_board_id(dev->coredev, board_id);
@@ -480,8 +478,7 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
rc = smsusb_start_streaming(dev);
if (rc < 0) {
pr_err("smsusb_start_streaming(...) failed\n");
- smsusb_term_device(intf);
- return rc;
+ goto terminate_device;
}
dev->state = SMSUSB_ACTIVE;
@@ -489,13 +486,17 @@ static int smsusb_init_device(struct usb_interface *intf, int board_id)
rc = smscore_start_device(dev->coredev);
if (rc < 0) {
pr_err("smscore_start_device(...) failed\n");
- smsusb_term_device(intf);
- return rc;
+ goto terminate_device;
}
pr_debug("device 0x%p created\n", dev);
return rc;
+
+terminate_device:
+ smsusb_term_device(intf);
+ kfree(mdev);
+ return rc;
}
static int smsusb_probe(struct usb_interface *intf,
--
2.14.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] [media] Siano: Use common error handling code in smsusb_init_device()
2017-09-20 12:40 [PATCH] [media] Siano: Use common error handling code in smsusb_init_device() SF Markus Elfring
@ 2017-09-20 13:56 ` Dan Carpenter
2017-09-20 17:18 ` SF Markus Elfring
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter @ 2017-09-20 13:56 UTC (permalink / raw)
To: SF Markus Elfring
Cc: linux-media, Mauro Carvalho Chehab, LKML, kernel-janitors
On Wed, Sep 20, 2017 at 02:40:28PM +0200, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Wed, 20 Sep 2017 14:30:55 +0200
>
> Add a jump target so that a bit of exception handling can be better
> reused at the end of this function.
>
> This refactoring might fix also an error situation where the
> function "kfree" was not called after a software failure
> was noticed in two cases.
>
No. It doesn't fix a leak, it introduces a double free. If
smscore_register_device() succeeds then mdev is freed when we call
smsusb_term_device(intf); The call tree is:
smsusb_term_device()
-> smscore_unregister_device()
-> smscore_notify_clients()
-> smsdvb_onremove()
-> smsdvb_unregister_client()
-> smsdvb_media_device_unregister()
-> kfree(coredev->media_dev);
regards,
dan carpenter
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [media] Siano: Use common error handling code in smsusb_init_device()
2017-09-20 13:56 ` Dan Carpenter
@ 2017-09-20 17:18 ` SF Markus Elfring
0 siblings, 0 replies; 3+ messages in thread
From: SF Markus Elfring @ 2017-09-20 17:18 UTC (permalink / raw)
To: Dan Carpenter, linux-media; +Cc: Mauro Carvalho Chehab, LKML, kernel-janitors
> If smscore_register_device() succeeds then mdev is freed when we call
> smsusb_term_device(intf); The call tree is:
Thanks for your constructive information.
How do you think about another implementation detail in this function then?
May the statement “kfree(mdev);” be executed before “smsusb_term_device(intf);”
in one if branch?
Regards,
Markus
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-09-20 12:40 [PATCH] [media] Siano: Use common error handling code in smsusb_init_device() SF Markus Elfring
2017-09-20 13:56 ` Dan Carpenter
2017-09-20 17:18 ` SF Markus Elfring
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