mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()

If 'aggr_interval' is smaller than 'sample_interval', max_nr_accesses in
damon_nr_accesses_to_accesses_bp() becomes zero which leads to divide
error, let's validate the values of them in damon_set_attrs() to fix it,
which similar to others attrs check.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 2f5bef5 ("mm/damon/core: update monitoring results for new monitoring attributes")
Reported-by: [email protected]
Closes: https://syzkaller.appspot.com/bug?extid=841a46899768ec7bec67
Link: https://lore.kernel.org/damon/[email protected]/
Reviewed-by: SeongJae Park <[email protected]>
Signed-off-by: Kefeng Wang <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: Kefeng Wang

mm/damon/core.c

@@ -551,6 +551,8 @@ int damon_set_attrs(struct damon_ctx *ctx, struct damon_attrs *attrs)
 		return -EINVAL;
 	if (attrs->min_nr_regions > attrs->max_nr_regions)
 		return -EINVAL;
+	if (attrs->sample_interval > attrs->aggr_interval)
+		return -EINVAL;
 
 	damon_update_monitoring_results(ctx, attrs);
 	ctx->attrs = *attrs;