9e32e288f0
This fixes a possible unbalanced dev_hold(): > iw dev bar del [ 237.355366] unregister_netdevice: waiting for bar to become free. Usage count = 1 [ 247.435362] unregister_netdevice: waiting for bar to become free. Usage count = 1 [ 257.545366] unregister_netdevice: waiting for bar to become free. Usage count = 1 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
70 lines
2.6 KiB
Diff
70 lines
2.6 KiB
Diff
From dd7590a3ab3f0804ed5e930295e2caa5979e3958 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Thu, 28 Feb 2019 22:57:33 +0100
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Subject: [PATCH] leds: trigger: netdev: fix refcnt leak on interface rename
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Renaming a netdev-trigger-tracked interface was resulting in an
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unbalanced dev_hold().
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Example:
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> iw phy phy0 interface add foo type __ap
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> echo netdev > trigger
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> echo foo > device_name
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> ip link set foo name bar
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> iw dev bar del
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[ 237.355366] unregister_netdevice: waiting for bar to become free. Usage count = 1
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[ 247.435362] unregister_netdevice: waiting for bar to become free. Usage count = 1
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[ 257.545366] unregister_netdevice: waiting for bar to become free. Usage count = 1
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Above problem was caused by trigger checking a dev->name which obviously
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changes after renaming an interface. It meant missing all further events
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including the NETDEV_UNREGISTER which is required for calling dev_put().
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This change fixes that by:
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1) Comparing device struct *address* for notification-filtering purposes
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2) Dropping unneeded NETDEV_CHANGENAME code (no behavior change)
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Fixes: 06f502f57d0d ("leds: trigger: Introduce a NETDEV trigger")
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Acked-by: Pavel Machek <pavel@ucw.cz>
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Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
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---
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drivers/leds/trigger/ledtrig-netdev.c | 13 +++++--------
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1 file changed, 5 insertions(+), 8 deletions(-)
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--- a/drivers/leds/trigger/ledtrig-netdev.c
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+++ b/drivers/leds/trigger/ledtrig-netdev.c
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@@ -299,11 +299,11 @@ static int netdev_trig_notify(struct not
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notifier);
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if (evt != NETDEV_UP && evt != NETDEV_DOWN && evt != NETDEV_CHANGE
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- && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER
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- && evt != NETDEV_CHANGENAME)
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+ && evt != NETDEV_REGISTER && evt != NETDEV_UNREGISTER)
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return NOTIFY_DONE;
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- if (strcmp(dev->name, trigger_data->device_name))
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+ if (!(dev == trigger_data->net_dev ||
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+ (evt == NETDEV_REGISTER && !strcmp(dev->name, trigger_data->device_name))))
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return NOTIFY_DONE;
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cancel_delayed_work_sync(&trigger_data->work);
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@@ -318,12 +318,9 @@ static int netdev_trig_notify(struct not
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dev_hold(dev);
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trigger_data->net_dev = dev;
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break;
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- case NETDEV_CHANGENAME:
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case NETDEV_UNREGISTER:
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- if (trigger_data->net_dev) {
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- dev_put(trigger_data->net_dev);
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- trigger_data->net_dev = NULL;
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- }
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+ dev_put(trigger_data->net_dev);
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+ trigger_data->net_dev = NULL;
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break;
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case NETDEV_UP:
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case NETDEV_CHANGE:
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