diff options
authorAnshuman Khandual <anshuman.khandual@arm.com>2018-10-05 15:51:51 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-05 16:32:04 -0700
commite6112fc300702f96374f34368513d57795fc6d23 (patch)
parent59cf0a9339ca4b0226e9b4329dfb0a5b8b0b9bc2 (diff)
mm/migrate.c: split only transparent huge pages when allocation fails
split_huge_page_to_list() fails on HugeTLB pages. I was experimenting with moving 32MB contig HugeTLB pages on arm64 (with a debug patch applied) and hit the following stack trace when the kernel crashed. [ 3732.462797] Call trace: [ 3732.462835] split_huge_page_to_list+0x3b0/0x858 [ 3732.462913] migrate_pages+0x728/0xc20 [ 3732.462999] soft_offline_page+0x448/0x8b0 [ 3732.463097] __arm64_sys_madvise+0x724/0x850 [ 3732.463197] el0_svc_handler+0x74/0x110 [ 3732.463297] el0_svc+0x8/0xc [ 3732.463347] Code: d1000400 f90b0e60 f2fbd5a2 a94982a1 (f9000420) When unmap_and_move[_huge_page]() fails due to lack of memory, the splitting should happen only for transparent huge pages not for HugeTLB pages. PageTransHuge() returns true for both THP and HugeTLB pages. Hence the conditonal check should test PagesHuge() flag to make sure that given pages is not a HugeTLB one. Link: http://lkml.kernel.org/r/1537798495-4996-1-git-send-email-anshuman.khandual@arm.com Fixes: 94723aafb9 ("mm: unclutter THP migration") Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 9d374011c244..9ba72c2365e6 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1414,7 +1414,7 @@ retry:
* we encounter them after the rest of the list
* is processed.
- if (PageTransHuge(page)) {
+ if (PageTransHuge(page) && !PageHuge(page)) {
rc = split_huge_page_to_list(page, from);