Hi, John Stultz <john.stultz@xxxxxxxxxx> writes: > 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@xxxxxxxxxxxxx> > Cc: Guodong Xu <guodong.xu@xxxxxxxxxx> > Cc: Amit Pundir <amit.pundir@xxxxxxxxxx> > Cc: Rob Herring <robh+dt@xxxxxxxxxx> > Cc: John Youn <johnyoun@xxxxxxxxxxxx> > Cc: Douglas Anderson <dianders@xxxxxxxxxxxx> > Cc: Chen Yu <chenyu56@xxxxxxxxxx> > Cc: Vardan Mikayelyan <mvardan@xxxxxxxxxxxx> > Cc: Kishon Vijay Abraham I <kishon@xxxxxx> > Cc: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> > Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: linux-usb@xxxxxxxxxxxxxxx > Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx> > --- doesn't apply to my testing/next. Please rebase -- balbi
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