mm/damon/core: avoid divide-by-zero during monitoring results update
authorSeongJae Park <sj@kernel.org>
Thu, 19 Oct 2023 19:49:21 +0000 (19:49 +0000)
committerAndrew Morton <akpm@linux-foundation.org>
Wed, 25 Oct 2023 23:47:15 +0000 (16:47 -0700)
commitd35963bfb05877455228ecec6b194f624489f96a
tree6ffa5dc3d756612c92fa5a33592aada553e8cd77
parent35f5d94187a6a3a8df2cba54beccca1c2379edb8
mm/damon/core: avoid divide-by-zero during monitoring results update

When monitoring attributes are changed, DAMON updates access rate of the
monitoring results accordingly.  For that, it divides some values by the
maximum nr_accesses.  However, due to the type of the related variables,
simple division-based calculation of the divisor can return zero.  As a
result, divide-by-zero is possible.  Fix it by using
damon_max_nr_accesses(), which handles the case.

Link: https://lkml.kernel.org/r/20231019194924.100347-3-sj@kernel.org
Fixes: 2f5bef5a590b ("mm/damon/core: update monitoring results for new monitoring attributes")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> [6.3+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/damon/core.c