UPSTREAM: mm/damon/core: initialize damon_target->list in damon_new_target()

'struct damon_target' creation function, 'damon_new_target()' is not
initializing its '->list' field, unlike other DAMON structs creator
functions such as 'damon_new_region()'.  Normal users of
'damon_new_target()' initializes the field by adding the target to DAMON
context's targets list, but some code could access the uninitialized
field.

This commit avoids the case by initializing the field in
'damon_new_target()'.

Bug: 254441685
Link: https://lkml.kernel.org/r/20221002193130.8227-1-sj@kernel.org


Fixes: f23b8eee ("mm/damon/core: implement region-based sampling")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit b1f44cda)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I42adfe86cbe78f45c04a66d486261234e16d463f