From 9c1ed62ae0690dfe5d5e31d8f70e70a95cb48e52 Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Wed, 18 Dec 2019 11:43:49 +0800 Subject: [PATCH] usb: gadget: udc: fix possible sleep-in-atomic-context bugs in gr_probe() The driver may sleep while holding a spinlock. The function call path (from bottom to top) in Linux 4.19 is: drivers/usb/gadget/udc/core.c, 1175: kzalloc(GFP_KERNEL) in usb_add_gadget_udc_release drivers/usb/gadget/udc/core.c, 1272: usb_add_gadget_udc_release in usb_add_gadget_udc drivers/usb/gadget/udc/gr_udc.c, 2186: usb_add_gadget_udc in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2183: spin_lock in gr_probe drivers/usb/gadget/udc/core.c, 1195: mutex_lock in usb_add_gadget_udc_release drivers/usb/gadget/udc/core.c, 1272: usb_add_gadget_udc_release in usb_add_gadget_udc drivers/usb/gadget/udc/gr_udc.c, 2186: usb_add_gadget_udc in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2183: spin_lock in gr_probe drivers/usb/gadget/udc/gr_udc.c, 212: debugfs_create_file in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2197: gr_dfs_create in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2183: spin_lock in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2114: devm_request_threaded_irq in gr_request_irq drivers/usb/gadget/udc/gr_udc.c, 2202: gr_request_irq in gr_probe drivers/usb/gadget/udc/gr_udc.c, 2183: spin_lock in gr_probe kzalloc(GFP_KERNEL), mutex_lock(), debugfs_create_file() and devm_request_threaded_irq() can sleep at runtime. To fix these possible bugs, usb_add_gadget_udc(), gr_dfs_create() and gr_request_irq() are called without handling the spinlock. These bugs are found by a static analysis tool STCheck written by myself. Signed-off-by: Jia-Ju Bai Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/udc/gr_udc.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/usb/gadget/udc/gr_udc.c b/drivers/usb/gadget/udc/gr_udc.c index 64d80c6..aaf975c 100644 --- a/drivers/usb/gadget/udc/gr_udc.c +++ b/drivers/usb/gadget/udc/gr_udc.c @@ -2175,8 +2175,6 @@ static int gr_probe(struct platform_device *pdev) return -ENOMEM; } - spin_lock(&dev->lock); - /* Inside lock so that no gadget can use this udc until probe is done */ retval = usb_add_gadget_udc(dev->dev, &dev->gadget); if (retval) { @@ -2185,15 +2183,21 @@ static int gr_probe(struct platform_device *pdev) } dev->added = 1; + spin_lock(&dev->lock); + retval = gr_udc_init(dev); - if (retval) + if (retval) { + spin_unlock(&dev->lock); goto out; - - gr_dfs_create(dev); + } /* Clear all interrupt enables that might be left on since last boot */ gr_disable_interrupts_and_pullup(dev); + spin_unlock(&dev->lock); + + gr_dfs_create(dev); + retval = gr_request_irq(dev, dev->irq); if (retval) { dev_err(dev->dev, "Failed to request irq %d\n", dev->irq); @@ -2222,8 +2226,6 @@ static int gr_probe(struct platform_device *pdev) dev_info(dev->dev, "regs: %p, irq %d\n", dev->regs, dev->irq); out: - spin_unlock(&dev->lock); - if (retval) gr_remove(pdev); -- 2.7.4