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Soeren Moch authored
commit 414abbd2 upstream. In dvb_ringbuffer lock-less synchronizationof reader and writer threads is done with separateread and write pointers. Sincedvb_ringbuffer_flush() modifies the read pointer, this function must not be called from the writer thread. This patch removes the dvb_ringbuffer_flush() calls in the dmxdev ringbuffer write functions, this fixes Oopses "Unable to handle kernel paging request" I could observe for the call chaindvb_demux_read ->dvb_dmxdev_buffer_read -> dvb_ringbuffer_read_user -> __copy_to_user (the reader side of the ringbuffer). The flush calls at the write side are not necessary anyway since ringbuffer_flush is also called in dvb_dmxdev_buffer_read() when an error condition is set in the ringbuffer. This patch should also be applied to stable kernels. Signed-off-by: Soeren Moch <smoch@web.de> Reviewed-by: Sakari Ailus <sakari.ailus@iki.fi> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com> [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Jianguo Wu <wujianguo@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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