usb: gadget: ffs: race between ffs_epfile_io() and ffs_func_eps_disable()
ffs_epfile_io() is called from userspace, while ffs_func_eps_disable() might be
called from USB disconnect interrupt, the two functions would run in parallel
but they are not well protected, that epfile->ep would be removed by
ffs_func_eps_disable() during ffs_epfile_io() is referring this pointer, then
it leads to kernel PANIC.
The scenario is as below:
Thread 1 Thread 2
| |
SyS_read dwc3_gadget_disconnect_interrupt
| |
ffs_epfile_read reset_config
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ffs_epfile_io ffs_func_eps_disable
| |
----- usb_ep_disable(): epfile->ep->ep->desc = NULL
| |
usb_ep_align_maybe(): -----
it refers ep->desc->wMaxPacketSize -----
Signed-off-by: Chao Bi <chao.bi@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
1 file changed