From: Vikram Pandita <vikram.pandita@xxxxxx>
User can trigger disabling of gadget at run time while the
transfers are going on.
Eg: 1: rmmod of musb driver while transfers are going on
Eg: 2: On android doing:
echo 0 > /sys/class/android_usb/android0/enable
While a big file transfer is going on via PTP/MTP.
In such a case, musb_gadget_disable() calls nuke()
but the dma interrupt may still happen for an endpoint since hw
would raise the interrupt in anycase.
This can result in a NULL pointer access crash:
[ 314.030426] PC is at txstate+0x74/0x20c
[ 314.034759] LR is at musb_g_tx+0x140/0x204
[ 314.039489] pc : [<c03506f4>] lr : [<c0350bcc>] psr: 20000193
[ 314.039520] sp : c783bc68 ip : 00000002 fp : c783bc9c
[ 314.052429] r10: 00000018 r9 : 00000000 r8 : 00000200
[ 314.058258] r7 : 00000000 r6 : fc0ab130 r5 : c781a410 r4 : c6caf640
[ 314.065643] r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : c781a000
[ 315.083251] Backtrace:
[ 315.086242] [<c0350680>] (txstate+0x0/0x20c) from [<c0350bcc>] (musb_g_tx+0x140/0x204)
[ 315.095123] [<c0350a8c>] (musb_g_tx+0x0/0x204) from [<c034eb00>] (musb_dma_completion+0x40/0x54)
[ 315.104980] [<c034eac0>] (musb_dma_completion+0x0/0x54) from [<c0351e6c>] (dma_controller_irq+0x118/0x184)
[ 315.115661] [<c0351d54>] (dma_controller_irq+0x0/0x184) from [<c00d86b8>] (handle_irq_event_percpu+0x54/0x188)
So put protection in code to handle possiblity of getting an interrupt for an
endpoint that might have been already nuked.
Reported-by: Todd Poynor <toddpoynor@xxxxxxxxxx>
Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
---
drivers/usb/musb/musb_gadget.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index f42c29b..695c892 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -328,6 +328,13 @@ static void txstate(struct musb *musb, struct musb_request *req)
musb_ep = req->ep;
+ /* Check if EP is disabled */
+ if (!musb_ep->desc) {
+ dev_dbg(musb->controller, "ep:%s disabled - ignore request\n",
+ musb_ep->end_point.name);
+ return;
+ }
+
/* we shouldn't get here while DMA is active ... but we do ... */
if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
dev_dbg(musb->controller, "dma pending...\n");
@@ -650,6 +657,13 @@ static void rxstate(struct musb *musb, struct musb_request *req)
len = musb_ep->packet_sz;
+ /* Check if EP is disabled */
+ if (!musb_ep->desc) {
+ dev_dbg(musb->controller, "ep:%s disabled - ignore request\n",
+ musb_ep->end_point.name);
+ return;
+ }
+
/* We shouldn't get here while DMA is active, but we do... */
if (dma_channel_status(musb_ep->dma) == MUSB_DMA_STATUS_BUSY) {
dev_dbg(musb->controller, "DMA pending...\n");
--
1.7.9.5
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