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Message-ID: <CA+icZUX+dHynV3A5AiGTGqC+iGR1psy9LUxtmFXNWaVCm+r2MQ@mail.gmail.com>
Date: Mon, 28 Sep 2015 09:17:38 +0200
From: Sedat Dilek <sedat.dilek@...il.com>
To: Jiri Kosina <jikos@...nel.org>
Cc: Tejun Heo <tj@...nel.org>, Lai Jiangshan <jiangshanlai@...il.com>,
LKML <linux-kernel@...r.kernel.org>, linux-input@...r.kernel.org,
Paul McKenney <paulmck@...ux.vnet.ibm.com>
Subject: Re: [Linux v4.2] workqueue: llvmlinux: acpid: BUG: sleeping function
called from invalid context at kernel/workqueue.c:2680
On Mon, Sep 28, 2015 at 8:50 AM, Sedat Dilek <sedat.dilek@...il.com> wrote:
> [ CC only relevant people plus Paul as he took care in another thread ]
>
> First of all, sorry for flooding anybody or any mailing-list.
>
> Of course, using LLVM/Clang for the Linux-kernel is still WIP, but
> this does not mean using a different compiler does not find any
> bugs...
>
> Fascinated somehow of this problem I entered the "tracing" area.
> I played a bit with tracing and irq-flags (hardirqs).
>
> This is what I discovered now.
>
> [ TEST-1 ]
>
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -731,6 +731,7 @@ void usbhid_close(struct hid_device *hid)
> */
> spin_lock_irq(&usbhid->lock);
> if (!--hid->open) {
> + trace_hardirqs_off();
> spin_unlock_irq(&usbhid->lock);
> hid_cancel_delayed_stuff(usbhid);
> if (!(hid->quirks & HID_QUIRK_ALWAYS_POLL)) {
> @@ -1392,6 +1393,8 @@ static void usbhid_disconnect(struct usb_interface *intf)
>
> static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
> {
> + might_sleep();
> +
> del_timer_sync(&usbhid->io_retry);
> cancel_work_sync(&usbhid->reset_work);
> }
>
> This makes the BUG line go away - only changes in the HID area.
>
> [ TEST-2 ]
>
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -732,6 +732,7 @@ void usbhid_close(struct hid_device *hid)
> spin_lock_irq(&usbhid->lock);
> if (!--hid->open) {
> spin_unlock_irq(&usbhid->lock);
> + trace_hardirqs_off();
> hid_cancel_delayed_stuff(usbhid);
> if (!(hid->quirks & HID_QUIRK_ALWAYS_POLL)) {
> usb_kill_urb(usbhid->urbin);
> @@ -1392,6 +1393,8 @@ static void usbhid_disconnect(struct usb_interface *intf)
>
> static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
> {
> + might_sleep();
> +
> del_timer_sync(&usbhid->io_retry);
> cancel_work_sync(&usbhid->reset_work);
> }
>
> This results in...
>
> [ 23.236024] BUG: sleeping function called from invalid context at
> drivers/hid/usbhid/hid-core.c:1396
> [ 23.236148] in_atomic(): 0, irqs_disabled(): 1, pid: 1419, name: acpid
> [ 23.236233] 3 locks held by acpid/1419:
> [ 23.236235] #0: (&evdev->mutex){+.+...}, at: [<ffffffff8174c98c>]
> evdev_release+0xbc/0xf0
> [ 23.236250] #1: (&dev->mutex#2){+.+...}, at: [<ffffffff817440a7>]
> input_close_device+0x27/0x70
> [ 23.236264] #2: (hid_open_mut){+.+...}, at: [<ffffffffa008e388>]
> usbhid_close+0x28/0xd0 [usbhid]
> [ 23.236277] irq event stamp: 3406
> [ 23.236280] hardirqs last enabled at (3405): [<ffffffff8192ccd2>]
> _raw_spin_unlock_irq+0x32/0x60
> [ 23.236286] hardirqs last disabled at (3406): [<ffffffffa008e3bd>]
> usbhid_close+0x5d/0xd0 [usbhid]
> [ 23.236292] softirqs last enabled at (2806): [<ffffffff818b3069>]
> local_bh_enable+0x9/0x20
> [ 23.236298] softirqs last disabled at (2804): [<ffffffff818b3049>]
> local_bh_disable+0x9/0x20
> [ 23.236306] CPU: 3 PID: 1419 Comm: acpid Not tainted
> 4.3.0-rc3-4-llvmlinux-amd64 #3
> [ 23.236309] Hardware name: SAMSUNG ELECTRONICS CO., LTD.
> 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013
> [ 23.236313] ffff8800c760b000 0000000000000096 0000000000000000
> ffff8800bce53c88
> [ 23.236320] ffffffff8149cabd ffff8800bce53cb8 ffffffff810cd5aa
> ffffffffa009780c
> [ 23.236328] ffff8800c5fd5740 0000000000000000 0000000000000574
> ffff8800bce53cf8
> [ 23.236334] Call Trace:
> [ 23.236342] [<ffffffff8149cabd>] dump_stack+0x7d/0xa0
> [ 23.236347] [<ffffffff810cd5aa>] ___might_sleep+0x28a/0x2a0
> [ 23.236351] [<ffffffff810cd2af>] __might_sleep+0x4f/0xc0
> [ 23.236357] [<ffffffffa008e3d5>] usbhid_close+0x75/0xd0 [usbhid]
> [ 23.236366] [<ffffffffa00714d1>] hidinput_close+0x31/0x40 [hid]
> [ 23.236373] [<ffffffffa00714a0>] ? hidinput_open+0x40/0x40 [hid]
> [ 23.236378] [<ffffffff817440c8>] input_close_device+0x48/0x70
> [ 23.236382] [<ffffffff8174c9a6>] evdev_release+0xd6/0xf0
> [ 23.236387] [<ffffffff81274367>] __fput+0x107/0x240
> [ 23.236392] [<ffffffff812741f6>] ____fput+0x16/0x20
> [ 23.236397] [<ffffffff810b97bc>] task_work_run+0x6c/0xe0
> [ 23.236403] [<ffffffff81003b8a>] prepare_exit_to_usermode+0x13a/0x140
> [ 23.236408] [<ffffffff81003e11>] syscall_return_slowpath+0x281/0x2f0
> [ 23.236414] [<ffffffff81270a45>] ? filp_close+0x65/0x90
> [ 23.236420] [<ffffffff810f02d9>] ? trace_hardirqs_on_caller+0x19/0x290
> [ 23.236425] [<ffffffff81003017>] ? trace_hardirqs_on_thunk+0x17/0x19
> [ 23.236431] [<ffffffff8192d9e2>] int_ret_from_sys_call+0x25/0x9f
>
> I will not do a statement :-).
>
> Looking at TEST-1, the spin_unlock_irq() within the if-statement seems
> to do cause problems with tracing / irq-flags.
>
> I have added my kernel-config, llvmlinux patchset, diffs with
> corresponding dmesg-logs (look into the attached tarball).
>
> Hope this really helps you.
>
I looked over some commits which had problems with tracing and
irq-flags (hardirq)...
[ TEST-3 ]
I am not an locking expert, when I replace...
spin_{un}lock_irq() with spin_{un}lock_bh()
...within usbhid_close() in drivers/hid/usbhid/hid-core.c...
This makes the BUG line go away for me.
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -729,16 +729,16 @@ void usbhid_close(struct hid_device *hid)
* data acquistion due to a resumption we no longer
* care about
*/
- spin_lock_irq(&usbhid->lock);
+ spin_lock_bh(&usbhid->lock);
if (!--hid->open) {
- spin_unlock_irq(&usbhid->lock);
+ spin_unlock_bh(&usbhid->lock);
hid_cancel_delayed_stuff(usbhid);
if (!(hid->quirks & HID_QUIRK_ALWAYS_POLL)) {
usb_kill_urb(usbhid->urbin);
usbhid->intf->needs_remote_wakeup = 0;
}
} else {
- spin_unlock_irq(&usbhid->lock);
+ spin_unlock_bh(&usbhid->lock);
}
mutex_unlock(&hid_open_mut);
}
@@ -1392,6 +1392,8 @@ static void usbhid_disconnect(struct usb_interface *intf)
static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
{
+ might_sleep();
+
del_timer_sync(&usbhid->io_retry);
cancel_work_sync(&usbhid->reset_work);
}
Does this help?
- Sedat -
View attachment "hid-core_c_test-3.diff" of type "text/plain" (1019 bytes)
View attachment "dmesg_4.3.0-rc3-4-llvmlinux-amd64_test-3.txt" of type "text/plain" (55435 bytes)
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