2017-09-26 15:11:41

by Andrey Konovalov

Subject: [PATCH v2] p54: don't unregister leds when they are not initialized

ieee80211_register_hw() in p54_register_common() may fail and leds won't
get initialized. Currently p54_unregister_common() doesn't check that and
always calls p54_unregister_leds(). The fix is to check priv->registered
flag before calling p54_unregister_leds().

Found by syzkaller.

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 1404 Comm: kworker/1:1 Not tainted
4.14.0-rc1-42251-gebb2c2437d80-dirty #205
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:16
dump_stack+0x292/0x395 lib/dump_stack.c:52
register_lock_class+0x6c4/0x1a00 kernel/locking/lockdep.c:769
__lock_acquire+0x27e/0x4550 kernel/locking/lockdep.c:3385
lock_acquire+0x259/0x620 kernel/locking/lockdep.c:4002
flush_work+0xf0/0x8c0 kernel/workqueue.c:2886
__cancel_work_timer+0x51d/0x870 kernel/workqueue.c:2961
cancel_delayed_work_sync+0x1f/0x30 kernel/workqueue.c:3081
p54_unregister_leds+0x6c/0xc0 drivers/net/wireless/intersil/p54/led.c:160
p54_unregister_common+0x3d/0xb0 drivers/net/wireless/intersil/p54/main.c:856
p54u_disconnect+0x86/0x120 drivers/net/wireless/intersil/p54/p54usb.c:1073
usb_unbind_interface+0x21c/0xa90 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:861
device_release_driver_internal+0x4f4/0x5c0 drivers/base/dd.c:893
device_release_driver+0x1e/0x30 drivers/base/dd.c:918
bus_remove_device+0x2f4/0x4b0 drivers/base/bus.c:565
device_del+0x5c4/0xab0 drivers/base/core.c:1985
usb_disable_device+0x1e9/0x680 drivers/usb/core/message.c:1170
usb_disconnect+0x260/0x7a0 drivers/usb/core/hub.c:2124
hub_port_connect drivers/usb/core/hub.c:4754
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x1318/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
process_scheduled_works kernel/workqueue.c:2179
worker_thread+0xb2b/0x1850 kernel/workqueue.c:2255
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

Signed-off-by: Andrey Konovalov <[email protected]>
---

changes in v2:
- fixed typo in patch subject

---
drivers/net/wireless/intersil/p54/main.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/intersil/p54/main.c b/drivers/net/wireless/intersil/p54/main.c
index d5a3bf91a03e..ab6d39e12069 100644
--- a/drivers/net/wireless/intersil/p54/main.c
+++ b/drivers/net/wireless/intersil/p54/main.c
@@ -852,12 +852,11 @@ void p54_unregister_common(struct ieee80211_hw *dev)
{
struct p54_common *priv = dev->priv;

-#ifdef CONFIG_P54_LEDS
- p54_unregister_leds(priv);
-#endif /* CONFIG_P54_LEDS */
-
if (priv->registered) {
priv->registered = false;
+#ifdef CONFIG_P54_LEDS
+ p54_unregister_leds(priv);
+#endif /* CONFIG_P54_LEDS */
ieee80211_unregister_hw(dev);
}

--
2.14.1.821.g8fa685d3b7-goog

2017-09-26 16:53:43

by Christian Lamparter

Subject: Re: [PATCH v2] p54: don't unregister leds when they are not initialized

On Tuesday, September 26, 2017 5:11:33 PM CEST Andrey Konovalov wrote:
> ieee80211_register_hw() in p54_register_common() may fail and leds won't
> get initialized. Currently p54_unregister_common() doesn't check that and
> always calls p54_unregister_leds(). The fix is to check priv->registered
> flag before calling p54_unregister_leds().
>
> Found by syzkaller.
>
> [...]
> process_scheduled_works kernel/workqueue.c:2179
> worker_thread+0xb2b/0x1850 kernel/workqueue.c:2255
> kthread+0x3a1/0x470 kernel/kthread.c:231
> ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
>
> Signed-off-by: Andrey Konovalov <[email protected]>
Cc: [email protected]
Acked-by: Christian Lamparter <[email protected]>

Thanks for making the patch too!