[PATCH 4.19 055/105] mm/hugetlb.c: dont put_page in lock of hugetlb_lock

From: Greg Kroah-Hartman
Date: Mon May 20 2019 - 08:50:37 EST


From: Kai Shen <shenkai8@xxxxxxxxxx>

commit 2bf753e64b4a702e27ce26ff520c59563c62f96b upstream.

spinlock recursion happened when do LTP test:
#!/bin/bash
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &
./runltp -p -f hugetlb &

The dtor returned by get_compound_page_dtor in __put_compound_page may be
the function of free_huge_page which will lock the hugetlb_lock, so don't
put_page in lock of hugetlb_lock.

BUG: spinlock recursion on CPU#0, hugemmap05/1079
lock: hugetlb_lock+0x0/0x18, .magic: dead4ead, .owner: hugemmap05/1079, .owner_cpu: 0
Call trace:
dump_backtrace+0x0/0x198
show_stack+0x24/0x30
dump_stack+0xa4/0xcc
spin_dump+0x84/0xa8
do_raw_spin_lock+0xd0/0x108
_raw_spin_lock+0x20/0x30
free_huge_page+0x9c/0x260
__put_compound_page+0x44/0x50
__put_page+0x2c/0x60
alloc_surplus_huge_page.constprop.19+0xf0/0x140
hugetlb_acct_memory+0x104/0x378
hugetlb_reserve_pages+0xe0/0x250
hugetlbfs_file_mmap+0xc0/0x140
mmap_region+0x3e8/0x5b0
do_mmap+0x280/0x460
vm_mmap_pgoff+0xf4/0x128
ksys_mmap_pgoff+0xb4/0x258
__arm64_sys_mmap+0x34/0x48
el0_svc_common+0x78/0x130
el0_svc_handler+0x38/0x78
el0_svc+0x8/0xc

Link: http://lkml.kernel.org/r/b8ade452-2d6b-0372-32c2-703644032b47@xxxxxxxxxx
Fixes: 9980d744a0 ("mm, hugetlb: get rid of surplus page accounting tricks")
Signed-off-by: Kai Shen <shenkai8@xxxxxxxxxx>
Signed-off-by: Feilong Lin <linfeilong@xxxxxxxxxx>
Reported-by: Wang Wang <wangwang2@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
mm/hugetlb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1572,8 +1572,9 @@ static struct page *alloc_surplus_huge_p
*/
if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
SetPageHugeTemporary(page);
+ spin_unlock(&hugetlb_lock);
put_page(page);
- page = NULL;
+ return NULL;
} else {
h->surplus_huge_pages++;
h->surplus_huge_pages_node[page_to_nid(page)]++;