Testing an USB drive connected to ohci-sm501 results in a large number of runtime warnings. WARNING: CPU: 0 PID: 0 at ./include/linux/dma-mapping.h:541 hcd_buffer_free+0x148/0x178 Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 4.18.0-rc7-00014-g7ec386e4c991-dirty PC is at hcd_buffer_free+0x148/0x178 PR is at hcd_buffer_free+0x66/0x178 PC : 8c26cbb0 SP : 8c481da8 SR : 400080f1 TEA : c00c8fe0 R0 : 000000f0 R1 : 000000f0 R2 : 8f9bb890 R3 : 00000000 R4 : 8f9c8800 R5 : 00001004 R6 : b07c6000 R7 : 007c6000 R8 : 00001004 R9 : 8f9bb814 R10 : 8c388104 R11 : 007c6000 R12 : b07c6000 R13 : 8f875680 R14 : 00000000 MACH: 000002fe MACL: 0000017c GBR : 00000000 PR : 8c26cace Call trace: [<(ptrval)>] usb_hcd_unmap_urb_for_dma+0xf4/0x13c [<(ptrval)>] arch_local_save_flags+0x0/0x8 [<(ptrval)>] __usb_hcd_giveback_urb+0x2e/0xdc [<(ptrval)>] arch_local_save_flags+0x0/0x8 [<(ptrval)>] finish_urb+0x8a/0x164 [<(ptrval)>] arch_local_save_flags+0x0/0x8 [<(ptrval)>] printk+0x0/0x48 [<(ptrval)>] ohci_work.part.11+0x150/0x41c [<(ptrval)>] td_done.isra.4+0x0/0x11c [<(ptrval)>] vprintk_default+0x14/0x20 [<(ptrval)>] arch_local_save_flags+0x0/0x8 [<(ptrval)>] ohci_irq+0x20c/0x314 [<(ptrval)>] usb_hcd_irq+0x16/0x28 Code analysis shows that interrupts are indeed disabled in ohci_irq(). Handle the situation by setting the HCD_BH flag in the ohci-sm501 driver. With this flag set, urbs are released in a tasklet and not by the interrupt handler. Fixes: f54aab6ebcecd ("usb: ohci-sm501 driver") Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> --- drivers/usb/host/ohci-sm501.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/ohci-sm501.c b/drivers/usb/host/ohci-sm501.c index c9233cddf9a2..eeb5b3137cf2 100644 --- a/drivers/usb/host/ohci-sm501.c +++ b/drivers/usb/host/ohci-sm501.c @@ -49,7 +49,7 @@ static const struct hc_driver ohci_sm501_hc_driver = { * generic hardware linkage */ .irq = ohci_irq, - .flags = HCD_USB11 | HCD_MEMORY | HCD_LOCAL_MEM, + .flags = HCD_USB11 | HCD_MEMORY | HCD_LOCAL_MEM | HCD_BH, /* * basic lifecycle operations -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html