From 44583fecfd85f33878a90ca9cad2eb533bfc39a1 Mon Sep 17 00:00:00 2001 From: Yunzhi Li Date: Tue, 29 Sep 2015 12:25:01 +0200 Subject: [PATCH] usb: dwc2: gadget: fix a memory use-after-free bug When dwc2_hsotg_handle_unaligned_buf_complete() hs_req->req.buf already destroyed, in dwc2_hsotg_unmap_dma(), it touches hs_req->req.dma again, so dwc2_hsotg_unmap_dma() should be called before dwc2_hsotg_handle_unaligned_buf_complete(). Otherwise, it will cause a bad_page BUG, when allocate this memory page next time. This bug led to the following crash: BUG: Bad page state in process swapper/0 pfn:2bdbc [ 26.820440] page:eed76780 count:0 mapcount:0 mapping: (null) index:0x0 [ 26.854710] page flags: 0x200(arch_1) [ 26.885836] page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set [ 26.919179] bad because of flags: [ 26.948917] page flags: 0x200(arch_1) [ 26.979100] Modules linked in: [ 27.008401] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W3.14.0 #17 [ 27.041816] [] (unwind_backtrace) from [] (show_stack+0x20/0x24) [ 27.076108] [] (show_stack) from [] (dump_stack+0x70/0x8c) [ 27.110246] [] (dump_stack) from [] (bad_page+0xfc/0x12c) [ 27.143958] [] (bad_page) from [] (get_page_from_freelist+0x3e4/0x50c) [ 27.179298] [] (get_page_from_freelist) from [] (__alloc_pages_nodemask) [ 27.216296] [] (__alloc_pages_nodemask) from [] (__get_free_pages+0x20/) [ 27.252326] [] (__get_free_pages) from [] (kmalloc_order_trace+0x34/0xa) [ 27.288295] [] (kmalloc_order_trace) from [] (__kmalloc+0x40/0x1ac) [ 27.323751] [] (__kmalloc) from [] (dwc2_hsotg_ep_queue.isra.12+0x7c/0x1) [ 27.359937] [] (dwc2_hsotg_ep_queue.isra.12) from [] (dwc2_hsotg_ep_queue) [ 27.397478] [] (dwc2_hsotg_ep_queue_lock) from [] (rx_submit+0xfc/0x164) [ 27.433619] [] (rx_submit) from [] (rx_complete+0x22c/0x230) [ 27.468872] [] (rx_complete) from [] (dwc2_hsotg_complete_request+0xfc/0) [ 27.506240] [] (dwc2_hsotg_complete_request) from [] (dwc2_hsotg_handle_o) [ 27.545401] [] (dwc2_hsotg_handle_outdone) from [] (dwc2_hsotg_epint+0x2c) [ 27.583689] [] (dwc2_hsotg_epint) from [] (dwc2_hsotg_irq+0x1dc/0x4ac) [ 27.621041] [] (dwc2_hsotg_irq) from [] (handle_irq_event_percpu+0x70/0x) [ 27.659066] [] (handle_irq_event_percpu) from [] (handle_irq_event+0x4c) [ 27.697322] [] (handle_irq_event) from [] (handle_fasteoi_irq+0xc8/0x11) [ 27.735451] [] (handle_fasteoi_irq) from [] (generic_handle_irq+0x30/0x) [ 27.773918] [] (generic_handle_irq) from [] (__handle_domain_irq+0x84/0) [ 27.812018] [] (__handle_domain_irq) from [] (gic_handle_irq+0x48/0x6c) [ 27.849695] [] (gic_handle_irq) from [] (__irq_svc+0x40/0x50) [ 27.886907] Exception stack(0xc0d01ee0 to 0xc0d01f28) Acked-by: John Youn Tested-by: Heiko Stuebner Tested-by: Jeffy Chen Signed-off-by: Yunzhi Li Signed-off-by: Felipe Balbi --- drivers/usb/dwc2/gadget.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c index bdda32cefeda..6dc64e9d05f9 100644 --- a/drivers/usb/dwc2/gadget.c +++ b/drivers/usb/dwc2/gadget.c @@ -1395,14 +1395,14 @@ static void dwc2_hsotg_complete_request(struct dwc2_hsotg *hsotg, if (hs_req->req.status == -EINPROGRESS) hs_req->req.status = result; + if (using_dma(hsotg)) + dwc2_hsotg_unmap_dma(hsotg, hs_ep, hs_req); + dwc2_hsotg_handle_unaligned_buf_complete(hsotg, hs_ep, hs_req); hs_ep->req = NULL; list_del_init(&hs_req->queue); - if (using_dma(hsotg)) - dwc2_hsotg_unmap_dma(hsotg, hs_ep, hs_req); - /* * call the complete request with the locks off, just in case the * request tries to queue more work for this endpoint. -- 2.20.1