Hi,
Fedora got a bug report of a regression when trying to remove the
the macsec module (https://bugzilla.redhat.com/show_bug.cgi?id=1566410).
I did a bisect and found
commit 5dcd8400884cc4a043a6d4617e042489e5d566a9
Author: Dan Carpenter <[email protected]>
Date: Wed Mar 21 11:09:01 2018 +0300
macsec: missing dev_put() on error in macsec_newlink()
We moved the dev_hold(real_dev); call earlier in the function but forgot
to update the error paths.
Fixes: 0759e552bce7 ("macsec: fix negative refcnt on parent link")
Signed-off-by: Dan Carpenter <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
The script I used for testing based on the reporter is attached. It
looks like modprobe is stuck in the D state. Any idea?
Thanks,
Laura
Hello Laura,
2018-04-14, 10:56:55 -0700, Laura Abbott wrote:
> Hi,
>
> Fedora got a bug report of a regression when trying to remove the
> the macsec module (https://bugzilla.redhat.com/show_bug.cgi?id=1566410).
> I did a bisect and found
>
> commit 5dcd8400884cc4a043a6d4617e042489e5d566a9
> Author: Dan Carpenter <[email protected]>
> Date: Wed Mar 21 11:09:01 2018 +0300
>
> macsec: missing dev_put() on error in macsec_newlink()
> We moved the dev_hold(real_dev); call earlier in the function but forgot
> to update the error paths.
> Fixes: 0759e552bce7 ("macsec: fix negative refcnt on parent link")
> Signed-off-by: Dan Carpenter <[email protected]>
> Signed-off-by: David S. Miller <[email protected]>
>
> The script I used for testing based on the reporter is attached. It
> looks like modprobe is stuck in the D state. Any idea?
I don't think that reference was actually leaked. It gets released in
macsec_free_netdev() when the device is deleted.
modprobe getting stuck is just a side-effect of the refcount going
negative on the parent device, since removing the module needs to take
the lock that is held by device deletion.
I'll send a revert tomorrow.
Thanks for the report,
--
Sabrina
This patch is just wrong, sorry. I was trying to fix a static checker
warning and misread the code. The reference taken in macsec_newlink()
is released in macsec_free_netdev() when the netdevice is destroyed.
This reverts commit 5dcd8400884cc4a043a6d4617e042489e5d566a9.
Reported-by: Laura Abbott <[email protected]>
Fixes: 5dcd8400884c ("macsec: missing dev_put() on error in macsec_newlink()")
Signed-off-by: Dan Carpenter <[email protected]>
Acked-by: Sabrina Dubroca <[email protected]>
---
I sent this earlier but I messed up the CC list. I've updated the
commit message as well.
drivers/net/macsec.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/net/macsec.c b/drivers/net/macsec.c
index 9cbb0c8a896a..7de88b33d5b9 100644
--- a/drivers/net/macsec.c
+++ b/drivers/net/macsec.c
@@ -3277,7 +3277,7 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
err = netdev_upper_dev_link(real_dev, dev, extack);
if (err < 0)
- goto put_dev;
+ goto unregister;
/* need to be already registered so that ->init has run and
* the MAC addr is set
@@ -3316,8 +3316,7 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
macsec_del_dev(macsec);
unlink:
netdev_upper_dev_unlink(real_dev, dev);
-put_dev:
- dev_put(real_dev);
+unregister:
unregister_netdevice(dev);
return err;
}
--
2.16.2
From: Dan Carpenter <[email protected]>
Date: Mon, 16 Apr 2018 13:17:50 +0300
> This patch is just wrong, sorry. I was trying to fix a static checker
> warning and misread the code. The reference taken in macsec_newlink()
> is released in macsec_free_netdev() when the netdevice is destroyed.
>
> This reverts commit 5dcd8400884cc4a043a6d4617e042489e5d566a9.
>
> Reported-by: Laura Abbott <[email protected]>
> Fixes: 5dcd8400884c ("macsec: missing dev_put() on error in macsec_newlink()")
> Signed-off-by: Dan Carpenter <[email protected]>
> Acked-by: Sabrina Dubroca <[email protected]>
> ---
> I sent this earlier but I messed up the CC list. I've updated the
> commit message as well.
Applied, thanks Dan.