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authorBin Liu <b-liu@ti.com>2016-05-26 19:43:45 +0300
committerFelipe Balbi <felipe.balbi@linux.intel.com>2016-05-31 11:12:54 +0300
commitd246dcb2331c5783743720e6510892eb1d2801d9 (patch)
tree8268ca8fee57b0460f7d01c7ea65322857329d1f /drivers/usb/gadget/legacy/inode.c
parent0015f9156092d07b3ec06d37d014328419d5832e (diff)
downloadlinux-d246dcb2331c5783743720e6510892eb1d2801d9.tar.xz
usb: gadget: fix spinlock dead lock in gadgetfs
[ 40.467381] ============================================= [ 40.473013] [ INFO: possible recursive locking detected ] [ 40.478651] 4.6.0-08691-g7f3db9a #37 Not tainted [ 40.483466] --------------------------------------------- [ 40.489098] usb/733 is trying to acquire lock: [ 40.493734] (&(&dev->lock)->rlock){-.....}, at: [<bf129288>] ep0_complete+0x18/0xdc [gadgetfs] [ 40.502882] [ 40.502882] but task is already holding lock: [ 40.508967] (&(&dev->lock)->rlock){-.....}, at: [<bf12a420>] ep0_read+0x20/0x5e0 [gadgetfs] [ 40.517811] [ 40.517811] other info that might help us debug this: [ 40.524623] Possible unsafe locking scenario: [ 40.524623] [ 40.530798] CPU0 [ 40.533346] ---- [ 40.535894] lock(&(&dev->lock)->rlock); [ 40.540088] lock(&(&dev->lock)->rlock); [ 40.544284] [ 40.544284] *** DEADLOCK *** [ 40.544284] [ 40.550461] May be due to missing lock nesting notation [ 40.550461] [ 40.557544] 2 locks held by usb/733: [ 40.561271] #0: (&f->f_pos_lock){+.+.+.}, at: [<c02a6114>] __fdget_pos+0x40/0x48 [ 40.569219] #1: (&(&dev->lock)->rlock){-.....}, at: [<bf12a420>] ep0_read+0x20/0x5e0 [gadgetfs] [ 40.578523] [ 40.578523] stack backtrace: [ 40.583075] CPU: 0 PID: 733 Comm: usb Not tainted 4.6.0-08691-g7f3db9a #37 [ 40.590246] Hardware name: Generic AM33XX (Flattened Device Tree) [ 40.596625] [<c010ffbc>] (unwind_backtrace) from [<c010c1bc>] (show_stack+0x10/0x14) [ 40.604718] [<c010c1bc>] (show_stack) from [<c04207fc>] (dump_stack+0xb0/0xe4) [ 40.612267] [<c04207fc>] (dump_stack) from [<c01886ec>] (__lock_acquire+0xf68/0x1994) [ 40.620440] [<c01886ec>] (__lock_acquire) from [<c0189528>] (lock_acquire+0xd8/0x238) [ 40.628621] [<c0189528>] (lock_acquire) from [<c06ad6b4>] (_raw_spin_lock_irqsave+0x38/0x4c) [ 40.637440] [<c06ad6b4>] (_raw_spin_lock_irqsave) from [<bf129288>] (ep0_complete+0x18/0xdc [gadgetfs]) [ 40.647339] [<bf129288>] (ep0_complete [gadgetfs]) from [<bf10a728>] (musb_g_giveback+0x118/0x1b0 [musb_hdrc]) [ 40.657842] [<bf10a728>] (musb_g_giveback [musb_hdrc]) from [<bf108768>] (musb_g_ep0_queue+0x16c/0x188 [musb_hdrc]) [ 40.668772] [<bf108768>] (musb_g_ep0_queue [musb_hdrc]) from [<bf12a944>] (ep0_read+0x544/0x5e0 [gadgetfs]) [ 40.678963] [<bf12a944>] (ep0_read [gadgetfs]) from [<c0284470>] (__vfs_read+0x20/0x110) [ 40.687414] [<c0284470>] (__vfs_read) from [<c0285324>] (vfs_read+0x88/0x114) [ 40.694864] [<c0285324>] (vfs_read) from [<c0286150>] (SyS_read+0x44/0x9c) [ 40.702051] [<c0286150>] (SyS_read) from [<c0107820>] (ret_fast_syscall+0x0/0x1c) This is caused by the spinlock bug in ep0_read(). Fix the two other deadlock sources in gadgetfs_setup() too. Cc: <stable@vger.kernel.org> # v3.16+ Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Diffstat (limited to 'drivers/usb/gadget/legacy/inode.c')
-rw-r--r--drivers/usb/gadget/legacy/inode.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index e64479f882a5..aa3707bdebb4 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -938,8 +938,11 @@ ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
struct usb_ep *ep = dev->gadget->ep0;
struct usb_request *req = dev->req;
- if ((retval = setup_req (ep, req, 0)) == 0)
- retval = usb_ep_queue (ep, req, GFP_ATOMIC);
+ if ((retval = setup_req (ep, req, 0)) == 0) {
+ spin_unlock_irq (&dev->lock);
+ retval = usb_ep_queue (ep, req, GFP_KERNEL);
+ spin_lock_irq (&dev->lock);
+ }
dev->state = STATE_DEV_CONNECTED;
/* assume that was SET_CONFIGURATION */
@@ -1457,8 +1460,11 @@ delegate:
w_length);
if (value < 0)
break;
+
+ spin_unlock (&dev->lock);
value = usb_ep_queue (gadget->ep0, dev->req,
- GFP_ATOMIC);
+ GFP_KERNEL);
+ spin_lock (&dev->lock);
if (value < 0) {
clean_req (gadget->ep0, dev->req);
break;
@@ -1481,11 +1487,14 @@ delegate:
if (value >= 0 && dev->state != STATE_DEV_SETUP) {
req->length = value;
req->zero = value < w_length;
- value = usb_ep_queue (gadget->ep0, req, GFP_ATOMIC);
+
+ spin_unlock (&dev->lock);
+ value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
if (value < 0) {
DBG (dev, "ep_queue --> %d\n", value);
req->status = 0;
}
+ return value;
}
/* device stalls when value < 0 */