tree 5e1458efefdac49cb85bee403953351c12d6df11
parent 51f2d1adaa3bceb4ee624b470d62be24f724be36
author Zhi Jin <zhi.jin@intel.com> 1536218530 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1553348109 +0100

stm class: Fix an endless loop in channel allocation

commit a1d75dad3a2c689e70a1c4e0214cca9de741d0aa upstream.

There is a bug in the channel allocation logic that leads to an endless
loop when looking for a contiguous range of channels in a range with a
mixture of free and occupied channels. For example, opening three
consequtive channels, closing the first two and requesting 4 channels in
a row will trigger this soft lockup. The bug is that the search loop
forgets to skip over the range once it detects that one channel in that
range is occupied.

Restore the original intent to the logic by fixing the omission.

Signed-off-by: Zhi Jin <zhi.jin@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices")
CC: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>