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commitcdafb6d8b8upstream. KASAN enabled configuration reports an error BUG: KASAN: use-after-free in ffs_free_inst+... [usb_f_fs] at addr ... Write of size 8 by task ... This is observed after "ffs-test" is run and interrupted. If after that functionfs is unmounted and g_ffs module is unloaded, that use-after-free occurs during g_ffs module removal. Although the report indicates ffs_free_inst() function, the actual use-after-free condition occurs in _ffs_free_dev() function, which is probably inlined into ffs_free_inst(). This happens due to keeping the ffs_data reference in device structure during functionfs unmounting, while ffs_data itself is freed as no longer needed. The fix is to clear that reference in ffs_closed() function, which is a counterpart of ffs_ready(), where the reference is stored. Fixes:3262ad8243("usb: gadget: f_fs: Stop ffs_closed NULL pointer dereference") Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>