Baolin Wang e77f4ddc7e mm/damon: validate if the pmd entry is present before accessing ... commit c8b9aff419 upstream. pmd_huge() is used to validate if the pmd entry is mapped by a huge page, also including the case of non-present (migration or hwpoisoned) pmd entry on arm64 or x86 architectures. This means that pmd_pfn() can not get the correct pfn number for a non-present pmd entry, which will cause damon_get_page() to get an incorrect page struct (also may be NULL by pfn_to_online_page()), making the access statistics incorrect. This means that the DAMON may make incorrect decision according to the incorrect statistics, for example, DAMON may can not reclaim cold page in time due to this cold page was regarded as accessed mistakenly if DAMOS_PAGEOUT operation is specified. Moreover it does not make sense that we still waste time to get the page of the non-present entry. Just treat it as not-accessed and skip it, which maintains consistency with non-present pte level entries. So add pmd entry present validation to fix the above issues. Link: https://lkml.kernel.org/r/58b1d1f5fbda7db49ca886d9ef6783e3dcbbbc98.1660805030.git.baolin.wang@linux.alibaba.com Fixes: 3f49584b26 ("mm/damon: implement primitives for the virtual memory address spaces") Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: SeongJae Park <sj@kernel.org> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-10-24 09:56:48 +02:00
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core-test.h	mm/damon/core-test: add a kunit test case for ops registration	2022-04-29 14:37:00 -07:00
core.c	mm/damon/vaddr: move 'damon_set_regions()' to core	2022-05-13 07:20:08 -07:00
dbgfs-test.h	mm/damon/dbgfs-test: fix is_target_id() change	2022-03-22 15:57:12 -07:00
dbgfs.c	mm/damon/dbgfs: fix memory leak when using debugfs_lookup()	2022-10-05 10:40:44 +02:00
Kconfig	mm/damon: implement a minimal stub for sysfs-based DAMON interface	2022-03-22 15:57:13 -07:00
Makefile	mm/damon: implement a minimal stub for sysfs-based DAMON interface	2022-03-22 15:57:13 -07:00
ops-common.c	mm: damon: use HPAGE_PMD_SIZE	2022-05-19 14:08:55 -07:00
ops-common.h	mm/damon: rename damon_primitives to damon_operations	2022-03-22 15:57:12 -07:00
paddr.c	mm: damon: use HPAGE_PMD_SIZE	2022-05-19 14:08:55 -07:00
reclaim.c	mm/damon/reclaim: fix potential memory leak in damon_reclaim_init()	2022-08-17 15:16:15 +02:00
sysfs.c	damon/sysfs: fix possible memleak on damon_sysfs_add_target	2022-10-05 10:40:55 +02:00
vaddr-test.h	mm/damon/vaddr: remove damon_va_apply_three_regions()	2022-05-13 07:20:08 -07:00
vaddr.c	mm/damon: validate if the pmd entry is present before accessing	2022-10-24 09:56:48 +02:00