6e6360b67d
Basically when plugging in various cables in different orders, I'm
occasionally seeing the following BUG splat:
[ 86.215403] BUG: scheduling while atomic: kworker/u16:2/53/0x00000002
[ 86.219164] usb 1-1: USB disconnect, device number 9
[ 86.226845] Preemption disabled at:[ 86.230218]
[<ffffff8008673558>] dwc2_conn_id_status_change+0x120/0x250
[ 86.236894] CPU: 0 PID: 53 Comm: kworker/u16:2 Tainted: G W
4.9.0-rc8-00051-gd5a7979-dirty #1702
[ 86.246836] Hardware name: HiKey Development Board (DT)
[ 86.252100] Workqueue: dwc2 dwc2_conn_id_status_change
[ 86.257279] Call trace:
[ 86.259771] [<ffffff8008087c28>] dump_backtrace+0x0/0x1a0
[ 86.265210] [<ffffff8008087ddc>] show_stack+0x14/0x20
[ 86.270308] [<ffffff80084343f0>] dump_stack+0x90/0xb0
[ 86.275401] [<ffffff80080d8d94>] __schedule_bug+0x6c/0xb8
[ 86.280841] [<ffffff8008a07220>] __schedule+0x4f8/0x5b0
[ 86.286099] [<ffffff8008a073e8>] schedule+0x38/0xa0
[ 86.291017] [<ffffff8008a0a6cc>] schedule_hrtimeout_range_clock+0x8c/0xf0
[ 86.297846] [<ffffff8008a0a740>] schedule_hrtimeout_range+0x10/0x18
[ 86.304150] [<ffffff8008a0a4a0>] usleep_range+0x50/0x58
[ 86.309418] [<ffffff800866d8dc>] dwc2_wait_for_mode.isra.4+0x54/0xd0
[ 86.315815] [<ffffff800866f058>] dwc2_core_reset+0xe0/0x168
[ 86.321431] [<ffffff800867e364>] dwc2_hsotg_core_init_disconnected+0x2c/0x310
[ 86.328602] [<ffffff8008673568>] dwc2_conn_id_status_change+0x130/0x250
[ 86.335254] [<ffffff80080ccd48>] process_one_work+0x118/0x370
[ 86.341035] [<ffffff80080ccfe8>] worker_thread+0x48/0x498
[ 86.346473] [<ffffff80080d2eb0>] kthread+0xd0/0xe8
[ 86.351299] [<ffffff8008082e80>] ret_from_fork+0x10/0x50
This seems to be caused by the dwc2_wait_for_mode() calling
usleep_range() while the hstog->lock spinlock is held, since
we take that before calling dwc2_hsotg_core_init_disconnected().
This patch avoids the issue by adding an extra argument to
dwc2_core_reset(), as suggested by John Youn, which allows us to
skip the waiting, which should be unnecessary when calling from
dwc2_hsotg_core_init_disconnected().
Cc: Wei Xu <xuwei5@hisilicon.com>
Cc: Guodong Xu <guodong.xu@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: John Youn <johnyoun@synopsys.com>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Chen Yu <chenyu56@huawei.com>
Cc: Vardan Mikayelyan <mvardan@synopsys.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.