From 618836cc3478aec3dc9a60488bfd43ca93a322bd Mon Sep 17 00:00:00 2001 From: Thomas Pugliese Date: Fri, 28 Feb 2014 14:31:55 -0600 Subject: [PATCH] usb: wusbcore: fix kernel panic on HWA unplug This patch adds ref counting to sections of code that operate on struct wa_xfer objects that were missing it. Specifically, error handling cases need to be protected from freeing the xfer while it is still in use elsewhere. This fixes a kernel panic that can occur when pulling the HWA dongle while data is being transferred to a wireless device. Signed-off-by: Thomas Pugliese Signed-off-by: Greg Kroah-Hartman --- drivers/usb/wusbcore/wa-xfer.c | 48 +++++++++++++++++++++++++++++++--- 1 file changed, 44 insertions(+), 4 deletions(-) diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c index 3cd96e936d77..3ca055555105 100644 --- a/drivers/usb/wusbcore/wa-xfer.c +++ b/drivers/usb/wusbcore/wa-xfer.c @@ -733,6 +733,8 @@ static void wa_seg_dto_cb(struct urb *urb) seg->isoc_frame_offset + seg->isoc_frame_index); /* resubmit the URB with the next isoc frame. */ + /* take a ref on resubmit. */ + wa_xfer_get(xfer); result = usb_submit_urb(seg->dto_urb, GFP_ATOMIC); if (result < 0) { dev_err(dev, "xfer 0x%08X#%u: DTO submit failed: %d\n", @@ -760,9 +762,13 @@ static void wa_seg_dto_cb(struct urb *urb) goto error_default; } + /* taken when this URB was submitted. */ + wa_xfer_put(xfer); return; error_dto_submit: + /* taken on resubmit attempt. */ + wa_xfer_put(xfer); error_default: spin_lock_irqsave(&xfer->lock, flags); rpipe = xfer->ep->hcpriv; @@ -788,7 +794,8 @@ error_default: wa_xfer_completion(xfer); if (rpipe_ready) wa_xfer_delayed_run(rpipe); - + /* taken when this URB was submitted. */ + wa_xfer_put(xfer); } /* @@ -855,6 +862,8 @@ static void wa_seg_iso_pack_desc_cb(struct urb *urb) if (rpipe_ready) wa_xfer_delayed_run(rpipe); } + /* taken when this URB was submitted. */ + wa_xfer_put(xfer); } /* @@ -931,6 +940,8 @@ static void wa_seg_tr_cb(struct urb *urb) if (rpipe_ready) wa_xfer_delayed_run(rpipe); } + /* taken when this URB was submitted. */ + wa_xfer_put(xfer); } /* @@ -1318,30 +1329,41 @@ static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer, /* default to done unless we encounter a multi-frame isoc segment. */ *dto_done = 1; + /* + * Take a ref for each segment urb so the xfer cannot disappear until + * all of the callbacks run. + */ + wa_xfer_get(xfer); /* submit the transfer request. */ + seg->status = WA_SEG_SUBMITTED; result = usb_submit_urb(&seg->tr_urb, GFP_ATOMIC); if (result < 0) { pr_err("%s: xfer %p#%u: REQ submit failed: %d\n", __func__, xfer, seg->index, result); - goto error_seg_submit; + wa_xfer_put(xfer); + goto error_tr_submit; } /* submit the isoc packet descriptor if present. */ if (seg->isoc_pack_desc_urb) { + wa_xfer_get(xfer); result = usb_submit_urb(seg->isoc_pack_desc_urb, GFP_ATOMIC); seg->isoc_frame_index = 0; if (result < 0) { pr_err("%s: xfer %p#%u: ISO packet descriptor submit failed: %d\n", __func__, xfer, seg->index, result); + wa_xfer_put(xfer); goto error_iso_pack_desc_submit; } } /* submit the out data if this is an out request. */ if (seg->dto_urb) { struct wahc *wa = xfer->wa; + wa_xfer_get(xfer); result = usb_submit_urb(seg->dto_urb, GFP_ATOMIC); if (result < 0) { pr_err("%s: xfer %p#%u: DTO submit failed: %d\n", __func__, xfer, seg->index, result); + wa_xfer_put(xfer); goto error_dto_submit; } /* @@ -1353,7 +1375,6 @@ static int __wa_seg_submit(struct wa_rpipe *rpipe, struct wa_xfer *xfer, && (seg->isoc_frame_count > 1)) *dto_done = 0; } - seg->status = WA_SEG_SUBMITTED; rpipe_avail_dec(rpipe); return 0; @@ -1361,7 +1382,7 @@ error_dto_submit: usb_unlink_urb(seg->isoc_pack_desc_urb); error_iso_pack_desc_submit: usb_unlink_urb(&seg->tr_urb); -error_seg_submit: +error_tr_submit: seg->status = WA_SEG_ERROR; seg->result = result; *dto_done = 1; @@ -1393,6 +1414,12 @@ static int __wa_xfer_delayed_run(struct wa_rpipe *rpipe, int *dto_waiting) list_node); list_del(&seg->list_node); xfer = seg->xfer; + /* + * Get a reference to the xfer in case the callbacks for the + * URBs submitted by __wa_seg_submit attempt to complete + * the xfer before this function completes. + */ + wa_xfer_get(xfer); result = __wa_seg_submit(rpipe, xfer, seg, &dto_done); /* release the dto resource if this RPIPE is done with it. */ if (dto_done) @@ -1404,10 +1431,15 @@ static int __wa_xfer_delayed_run(struct wa_rpipe *rpipe, int *dto_waiting) spin_unlock_irqrestore(&rpipe->seg_lock, flags); spin_lock_irqsave(&xfer->lock, flags); __wa_xfer_abort(xfer); + /* + * This seg was marked as submitted when it was put on + * the RPIPE seg_list. Mark it done. + */ xfer->segs_done++; spin_unlock_irqrestore(&xfer->lock, flags); spin_lock_irqsave(&rpipe->seg_lock, flags); } + wa_xfer_put(xfer); } /* * Mark this RPIPE as waiting if dto was not acquired, there are @@ -1592,12 +1624,19 @@ static int wa_urb_enqueue_b(struct wa_xfer *xfer) dev_err(&(urb->dev->dev), "%s: error_xfer_setup\n", __func__); goto error_xfer_setup; } + /* + * Get a xfer reference since __wa_xfer_submit starts asynchronous + * operations that may try to complete the xfer before this function + * exits. + */ + wa_xfer_get(xfer); result = __wa_xfer_submit(xfer); if (result < 0) { dev_err(&(urb->dev->dev), "%s: error_xfer_submit\n", __func__); goto error_xfer_submit; } spin_unlock_irqrestore(&xfer->lock, flags); + wa_xfer_put(xfer); return 0; /* @@ -1623,6 +1662,7 @@ error_xfer_submit: spin_unlock_irqrestore(&xfer->lock, flags); if (done) wa_xfer_completion(xfer); + wa_xfer_put(xfer); /* return success since the completion routine will run. */ return 0; } -- 2.30.2