[PATCH] brcmfmac: unlink URB when request timed out

[Mathy Vanhoef <vanhoefm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

From: Mathy Vanhoef <vanhoefm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Unlink the submitted URB in brcmf_usb_dl_cmd if the request timed out. This
assures the URB is never submitted twice, preventing a driver crash.

Signed-off-by: Mathy Vanhoef <vanhoefm-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
Currently brcmfmac may crash when a USB device is attached (tested with a LG
TWFM-B003D). In particular it fails on the second call to brcmf_usb_dl_cmd in
the while loop of brcmf_usb_resetcfg. The problem is that an URB is being
submitted twice:

[  169.861800] brcmfmac: brcmf_usb_dl_writeimage Enter, fw f14db000, len 348160
[  171.787791] brcmfmac: brcmf_usb_dl_writeimage Exit, err=0
[  171.787797] brcmfmac: brcmf_usb_dlstart Exit, err=0
[  171.787799] brcmfmac: brcmf_usb_dlrun Enter
[  171.791794] brcmfmac: brcmf_usb_resetcfg Enter
[  173.988072] ------------[ cut here ]------------
[  173.988083] WARNING: CPU: 0 PID: 369 at drivers/usb/core/urb.c:339 usb_submit_urb+0x4e6/0x500()
[  173.988085] URB eaf45f00 submitted while active
[  173.988086] Modules linked in: brcmfmac brcmutil vmw_pvscsi pcnet32 mptspi mptscsih mptbase
[  173.988100] CPU: 0 PID: 369 Comm: kworker/0:2 Not tainted 3.18.0-rc3-wl #1
[  173.988102] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
[  173.988106] Workqueue: events request_firmware_work_func
[  173.988108]  00000000 00000000 ee747db8 c1711f4a ee747df8 ee747de8 c103edaf c18d1e10
[  173.988112]  ee747e14 00000171 c18a8b29 00000153 c1490556 c1490556 eaf45f00 eafdc660
[  173.988115]  f14b8fa0 ee747e00 c103ee4e 00000009 ee747df8 c18d1e10 ee747e14 ee747e50
[  173.988119] Call Trace:
[  173.988129]  [<c1711f4a>] dump_stack+0x41/0x52
[  173.988136]  [<c103edaf>] warn_slowpath_common+0x7f/0xa0
[  173.988139]  [<c1490556>] ? usb_submit_urb+0x4e6/0x500
[  173.988141]  [<c1490556>] ? usb_submit_urb+0x4e6/0x500
[  173.988147]  [<f14b8fa0>] ? brcmf_usb_ioctl_resp_wake+0x40/0x40 [brcmfmac]
[  173.988150]  [<c103ee4e>] warn_slowpath_fmt+0x2e/0x30
[  173.988152]  [<c1490556>] usb_submit_urb+0x4e6/0x500
[  173.988156]  [<c1123de1>] ? __kmalloc+0x21/0x140
[  173.988161]  [<f14b91c3>] ? brcmf_usb_dl_cmd+0x33/0x120 [brcmfmac]
[  173.988166]  [<f14b9243>] brcmf_usb_dl_cmd+0xb3/0x120 [brcmfmac]
[  173.988170]  [<f14ba6c4>] brcmf_usb_probe_phase2+0x4e4/0x640 [brcmfmac]
[  173.988176]  [<f14b4900>] brcmf_fw_request_code_done+0xd0/0xf0 [brcmfmac]
[  173.988178]  [<c1400876>] request_firmware_work_func+0x26/0x50
[  173.988182]  [<c10513ee>] process_one_work+0x11e/0x360
[  173.988184]  [<c1051750>] worker_thread+0xf0/0x3c0
[  173.988205]  [<c106e14a>] ? __wake_up_locked+0x1a/0x20
[  173.988208]  [<c1051660>] ? process_scheduled_works+0x30/0x30
[  173.988211]  [<c1055b56>] kthread+0x96/0xb0
[  173.988214]  [<c1719c81>] ret_from_kernel_thread+0x21/0x30
[  173.988217]  [<c1055ac0>] ? kthread_worker_fn+0x110/0x110
[  173.988219] ---[ end trace 0c88bf46801de083 ]---
[  173.988221] brcmf_usb_dl_cmd: usb_submit_urb failed -16
[  173.988396] brcmfmac: brcmf_usb_probe_phase2 failed: dev=1-1, err=-19
[  173.989503] brcmfmac: brcmf_usb_disconnect Enter

This patch fixes the brcmf_usb_dl_cmd function to prevent an URB from being
submitted twice. Tested using a LG TWFM-B003D, which now works properly.


 drivers/net/wireless/brcm80211/brcmfmac/usb.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
index 5265aa7..1bc7858 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
@@ -738,10 +738,12 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info *devinfo, u8 cmd,
 		goto finalize;
 	}
 
-	if (!brcmf_usb_ioctl_resp_wait(devinfo))
+	if (!brcmf_usb_ioctl_resp_wait(devinfo)) {
+		usb_unlink_urb(devinfo->ctl_urb);
 		ret = -ETIMEDOUT;
-	else
+	} else {
 		memcpy(buffer, tmpbuf, buflen);
+	}
 
 finalize:
 	kfree(tmpbuf);
-- 
1.7.10.4

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