git.openwrt.org Git - openwrt/staging/xback.git/blob

   1 From db3b9e2e1d58080d0754bdf9293dabf8c6491b67 Mon Sep 17 00:00:00 2001
   2 From: Piotr Figiel <p.figiel@camlintechnologies.com>
   3 Date: Fri, 8 Mar 2019 15:25:04 +0000
   4 Subject: [PATCH] brcmfmac: fix race during disconnect when USB completion is
   5  in progress
   6
   7 It was observed that rarely during USB disconnect happening shortly after
   8 connect (before full initialization completes) usb_hub_wq would wait
   9 forever for the dev_init_lock to be unlocked. dev_init_lock would remain
  10 locked though because of infinite wait during usb_kill_urb:
  11
  12 [ 2730.656472] kworker/0:2     D    0   260      2 0x00000000
  13 [ 2730.660700] Workqueue: events request_firmware_work_func
  14 [ 2730.664807] [<809dca20>] (__schedule) from [<809dd164>] (schedule+0x4c/0xac)
  15 [ 2730.670587] [<809dd164>] (schedule) from [<8069af44>] (usb_kill_urb+0xdc/0x114)
  16 [ 2730.676815] [<8069af44>] (usb_kill_urb) from [<7f258b50>] (brcmf_usb_free_q+0x34/0xa8 [brcmfmac])
  17 [ 2730.684833] [<7f258b50>] (brcmf_usb_free_q [brcmfmac]) from [<7f2517d4>] (brcmf_detach+0xa0/0xb8 [brcmfmac])
  18 [ 2730.693557] [<7f2517d4>] (brcmf_detach [brcmfmac]) from [<7f251a34>] (brcmf_attach+0xac/0x3d8 [brcmfmac])
  19 [ 2730.702094] [<7f251a34>] (brcmf_attach [brcmfmac]) from [<7f2587ac>] (brcmf_usb_probe_phase2+0x468/0x4a0 [brcmfmac])
  20 [ 2730.711601] [<7f2587ac>] (brcmf_usb_probe_phase2 [brcmfmac]) from [<7f252888>] (brcmf_fw_request_done+0x194/0x220 [brcmfmac])
  21 [ 2730.721795] [<7f252888>] (brcmf_fw_request_done [brcmfmac]) from [<805748e4>] (request_firmware_work_func+0x4c/0x88)
  22 [ 2730.731125] [<805748e4>] (request_firmware_work_func) from [<80141474>] (process_one_work+0x228/0x808)
  23 [ 2730.739223] [<80141474>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564)
  24 [ 2730.746105] [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c)
  25 [ 2730.752227] [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20)
  26
  27 [ 2733.099695] kworker/0:3     D    0  1065      2 0x00000000
  28 [ 2733.103926] Workqueue: usb_hub_wq hub_event
  29 [ 2733.106914] [<809dca20>] (__schedule) from [<809dd164>] (schedule+0x4c/0xac)
  30 [ 2733.112693] [<809dd164>] (schedule) from [<809e2a8c>] (schedule_timeout+0x214/0x3e4)
  31 [ 2733.119621] [<809e2a8c>] (schedule_timeout) from [<809dde2c>] (wait_for_common+0xc4/0x1c0)
  32 [ 2733.126810] [<809dde2c>] (wait_for_common) from [<7f258d00>] (brcmf_usb_disconnect+0x1c/0x4c [brcmfmac])
  33 [ 2733.135206] [<7f258d00>] (brcmf_usb_disconnect [brcmfmac]) from [<8069e0c8>] (usb_unbind_interface+0x5c/0x1e4)
  34 [ 2733.143943] [<8069e0c8>] (usb_unbind_interface) from [<8056d3e8>] (device_release_driver_internal+0x164/0x1fc)
  35 [ 2733.152769] [<8056d3e8>] (device_release_driver_internal) from [<8056c078>] (bus_remove_device+0xd0/0xfc)
  36 [ 2733.161138] [<8056c078>] (bus_remove_device) from [<8056977c>] (device_del+0x11c/0x310)
  37 [ 2733.167939] [<8056977c>] (device_del) from [<8069cba8>] (usb_disable_device+0xa0/0x1cc)
  38 [ 2733.174743] [<8069cba8>] (usb_disable_device) from [<8069507c>] (usb_disconnect+0x74/0x1dc)
  39 [ 2733.181823] [<8069507c>] (usb_disconnect) from [<80695e88>] (hub_event+0x478/0xf88)
  40 [ 2733.188278] [<80695e88>] (hub_event) from [<80141474>] (process_one_work+0x228/0x808)
  41 [ 2733.194905] [<80141474>] (process_one_work) from [<80141a80>] (worker_thread+0x2c/0x564)
  42 [ 2733.201724] [<80141a80>] (worker_thread) from [<80147bcc>] (kthread+0x13c/0x16c)
  43 [ 2733.207913] [<80147bcc>] (kthread) from [<801010b4>] (ret_from_fork+0x14/0x20)
  44
  45 It was traced down to a case where usb_kill_urb would be called on an URB
  46 structure containing more or less random data, including large number in
  47 its use_count. During the debugging it appeared that in brcmf_usb_free_q()
  48 the traversal over URBs' lists is not synchronized with operations on those
  49 lists in brcmf_usb_rx_complete() leading to handling
  50 brcmf_usbdev_info structure (holding lists' head) as lists' element and in
  51 result causing above problem.
  52
  53 Fix it by walking through all URBs during brcmf_cancel_all_urbs using the
  54 arrays of requests instead of linked lists.
  55
  56 Signed-off-by: Piotr Figiel <p.figiel@camlintechnologies.com>
  57 Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
  58 ---
  59  drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c | 10 ++++++++--
  60  1 file changed, 8 insertions(+), 2 deletions(-)
  61
  62 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
  63 +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
  64 @@ -682,12 +682,18 @@ static int brcmf_usb_up(struct device *d
  65
  66  static void brcmf_cancel_all_urbs(struct brcmf_usbdev_info *devinfo)
  67  {
  68 +       int i;
  69 +
  70         if (devinfo->ctl_urb)
  71                 usb_kill_urb(devinfo->ctl_urb);
  72         if (devinfo->bulk_urb)
  73                 usb_kill_urb(devinfo->bulk_urb);
  74 -       brcmf_usb_free_q(&devinfo->tx_postq, true);
  75 -       brcmf_usb_free_q(&devinfo->rx_postq, true);
  76 +       if (devinfo->tx_reqs)
  77 +               for (i = 0; i < devinfo->bus_pub.ntxq; i++)
  78 +                       usb_kill_urb(devinfo->tx_reqs[i].urb);
  79 +       if (devinfo->rx_reqs)
  80 +               for (i = 0; i < devinfo->bus_pub.nrxq; i++)
  81 +                       usb_kill_urb(devinfo->rx_reqs[i].urb);
  82  }
  83
  84  static void brcmf_usb_down(struct device *dev)