redirector filter driver read accees violation

Hi All

i am developing redirector filter driver.
when my filter driver receives read request,
it builds new IRP and passes low level driver of local file system.

it can read data successfully at the first time
but second read operation causes access violation in NTOSKRL.

windbg shows error message


(0xC0000005, 0x804bb954, 0x00000000, 0x00000008)

Thanks for help
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