netdev - Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are flushed or cancelled

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Date:   Wed, 28 Jul 2021 23:25:19 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Mattijs Korpershoek <mkorpershoek@...libre.com>
Cc:     Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Fabien Parent <fparent@...libre.com>,
        Sean Wang <sean.wang@...iatek.com>,
        "open list:BLUETOOTH SUBSYSTEM" <linux-bluetooth@...r.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] Bluetooth: Shutdown controller after workqueues are
 flushed or cancelled

On Wed, Jul 28, 2021 at 9:50 PM Mattijs Korpershoek
<mkorpershoek@...libre.com> wrote:
>
> Hi Kai-Heng, Marcel,
>
> Marcel Holtmann <marcel@...tmann.org> writes:
>
> > Hi Kai-Heng,
> >
> >> Rfkill block and unblock Intel USB Bluetooth [8087:0026] may make it
> >> stops working:
> >> [  509.691509] Bluetooth: hci0: HCI reset during shutdown failed
> >> [  514.897584] Bluetooth: hci0: MSFT filter_enable is already on
> >> [  530.044751] usb 3-10: reset full-speed USB device number 5 using xhci_hcd
> >> [  545.660350] usb 3-10: device descriptor read/64, error -110
> >> [  561.283530] usb 3-10: device descriptor read/64, error -110
> >> [  561.519682] usb 3-10: reset full-speed USB device number 5 using xhci_hcd
> >> [  566.686650] Bluetooth: hci0: unexpected event for opcode 0x0500
> >> [  568.752452] Bluetooth: hci0: urb 0000000096cd309b failed to resubmit (113)
> >> [  578.797955] Bluetooth: hci0: Failed to read MSFT supported features (-110)
> >> [  586.286565] Bluetooth: hci0: urb 00000000c522f633 failed to resubmit (113)
> >> [  596.215302] Bluetooth: hci0: Failed to read MSFT supported features (-110)
> >>
> >> Or kernel panics because other workqueues already freed skb:
> >> [ 2048.663763] BUG: kernel NULL pointer dereference, address: 0000000000000000
> >> [ 2048.663775] #PF: supervisor read access in kernel mode
> >> [ 2048.663779] #PF: error_code(0x0000) - not-present page
> >> [ 2048.663782] PGD 0 P4D 0
> >> [ 2048.663787] Oops: 0000 [#1] SMP NOPTI
> >> [ 2048.663793] CPU: 3 PID: 4491 Comm: rfkill Tainted: G        W         5.13.0-rc1-next-20210510+ #20
> >> [ 2048.663799] Hardware name: HP HP EliteBook 850 G8 Notebook PC/8846, BIOS T76 Ver. 01.01.04 12/02/2020
> >> [ 2048.663801] RIP: 0010:__skb_ext_put+0x6/0x50
> >> [ 2048.663814] Code: 8b 1b 48 85 db 75 db 5b 41 5c 5d c3 be 01 00 00 00 e8 de 13 c0 ff eb e7 be 02 00 00 00 e8 d2 13 c0 ff eb db 0f 1f 44 00 00 55 <8b> 07 48 89 e5 83 f8 01 74 14 b8 ff ff ff ff f0 0f c1
> >> 07 83 f8 01
> >> [ 2048.663819] RSP: 0018:ffffc1d105b6fd80 EFLAGS: 00010286
> >> [ 2048.663824] RAX: 0000000000000000 RBX: ffff9d9ac5649000 RCX: 0000000000000000
> >> [ 2048.663827] RDX: ffffffffc0d1daf6 RSI: 0000000000000206 RDI: 0000000000000000
> >> [ 2048.663830] RBP: ffffc1d105b6fd98 R08: 0000000000000001 R09: ffff9d9ace8ceac0
> >> [ 2048.663834] R10: ffff9d9ace8ceac0 R11: 0000000000000001 R12: ffff9d9ac5649000
> >> [ 2048.663838] R13: 0000000000000000 R14: 00007ffe0354d650 R15: 0000000000000000
> >> [ 2048.663843] FS:  00007fe02ab19740(0000) GS:ffff9d9e5f8c0000(0000) knlGS:0000000000000000
> >> [ 2048.663849] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> >> [ 2048.663853] CR2: 0000000000000000 CR3: 0000000111a52004 CR4: 0000000000770ee0
> >> [ 2048.663856] PKRU: 55555554
> >> [ 2048.663859] Call Trace:
> >> [ 2048.663865]  ? skb_release_head_state+0x5e/0x80
> >> [ 2048.663873]  kfree_skb+0x2f/0xb0
> >> [ 2048.663881]  btusb_shutdown_intel_new+0x36/0x60 [btusb]
> >> [ 2048.663905]  hci_dev_do_close+0x48c/0x5e0 [bluetooth]
> >> [ 2048.663954]  ? __cond_resched+0x1a/0x50
> >> [ 2048.663962]  hci_rfkill_set_block+0x56/0xa0 [bluetooth]
> >> [ 2048.664007]  rfkill_set_block+0x98/0x170
> >> [ 2048.664016]  rfkill_fop_write+0x136/0x1e0
> >> [ 2048.664022]  vfs_write+0xc7/0x260
> >> [ 2048.664030]  ksys_write+0xb1/0xe0
> >> [ 2048.664035]  ? exit_to_user_mode_prepare+0x37/0x1c0
> >> [ 2048.664042]  __x64_sys_write+0x1a/0x20
> >> [ 2048.664048]  do_syscall_64+0x40/0xb0
> >> [ 2048.664055]  entry_SYSCALL_64_after_hwframe+0x44/0xae
> >> [ 2048.664060] RIP: 0033:0x7fe02ac23c27
> >> [ 2048.664066] Code: 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
> >> [ 2048.664070] RSP: 002b:00007ffe0354d638 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> >> [ 2048.664075] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fe02ac23c27
> >> [ 2048.664078] RDX: 0000000000000008 RSI: 00007ffe0354d650 RDI: 0000000000000003
> >> [ 2048.664081] RBP: 0000000000000000 R08: 0000559b05998440 R09: 0000559b05998440
> >> [ 2048.664084] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
> >> [ 2048.664086] R13: 0000000000000000 R14: ffffffff00000000 R15: 00000000ffffffff
> >>
> >> So move the shutdown callback to a place where workqueues are either
> >> flushed or cancelled to resolve the issue.
> >>
> >> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
> >> ---
> >> v2:
> >> - Rebased on bluetooth-next.
> >>
> >> net/bluetooth/hci_core.c | 16 ++++++++--------
> >> 1 file changed, 8 insertions(+), 8 deletions(-)
> >
> > patch has been applied to bluetooth-next tree.
>
> This patch seems to introduce a regression in the btmtksdio driver.
> With this patch applied, I can't enable the hci0 interface anymore on mt8183-pumpkin:
>
> i500-pumpkin login: root
> root@...0-pumpkin:~# uname -a
> Linux i500-pumpkin 5.14.0-rc3 #94 SMP PREEMPT Wed Jul 28 11:58:20 CEST 2021 aarch64 aarch64 aarch64 GNU/Linux
> root@...0-pumpkin:~# hciconfig hci0 up
> Can't init device hci0: Connection timed out (110)
> root@...0-pumpkin:~# hciconfig hci0 down
> root@...0-pumpkin:~# hciconfig hci0 up
> Can't init device hci0: Input/output error (5)
>
> Reverting it fixes the above issue.
> Any suggestion on how to fix this without touching hci_core ?
> Maybe the btmtksdio driver needs some rework. As I'm not familiar with the code, I would appreciate any tips.

Can you please attach dmesg?  Also, full ftrace log on btmtksdio can
also be helpful.

Kai-Heng

>
> Thanks,
> Mattijs Korpershoek
>
>
> >
> > Regards
> >
> > Marcel