On Thu, Aug 08, 2024, Selvarasu Ganesan wrote:
This commit addresses an issue where the USB core could access an invalid event buffer address during runtime suspend, potentially causing SMMU faults and other memory issues. The problem arises from the following sequence. 1. In dwc3_gadget_suspend, there is a chance of a timeout when moving the USB core to the halt state after clearing the run/stop bit by software. 2. In dwc3_core_exit, the event buffer is cleared regardless of the USB core's status, which may lead to an SMMU faults and
This is a workaround to your specific setup behavior. Please document in the commit message which platforms are impacted.
other memory issues. if the USB core tries to access the event buffer address.To prevent this issue, this commit ensures that the event buffer address is not cleared by software when the USB core is active during runtime suspend by checking its status before clearing the buffer address.
Cc: stable@vger.kernel.org
We can keep the stable tag, but there's no issue with the commit below.
Fixes: 89d7f9629946 ("usb: dwc3: core: Skip setting event buffers for host only controllers") Signed-off-by: Selvarasu Ganesan selvarasu.g@samsung.com
Changes in v2:
- Added separate check for USB controller status before cleaning the event buffer.
- Link to v1: https://urldefense.com/v3/__https://lore.kernel.org/lkml/20240722145617.537-...
drivers/usb/dwc3/core.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c index 734de2a8bd21..5b67d9bca71b 100644 --- a/drivers/usb/dwc3/core.c +++ b/drivers/usb/dwc3/core.c @@ -564,10 +564,15 @@ int dwc3_event_buffers_setup(struct dwc3 *dwc) void dwc3_event_buffers_cleanup(struct dwc3 *dwc) { struct dwc3_event_buffer *evt;
- u32 reg;
if (!dwc->ev_buf) return;
Please add comment here why we need this and which platform is impacted should we need to go back and test.
- reg = dwc3_readl(dwc->regs, DWC3_DSTS);
- if (!(reg & DWC3_DSTS_DEVCTRLHLT))
return;- evt = dwc->ev_buf;
evt->lpos = 0; -- 2.17.1
Thanks, Thinh