syzbot

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BUG: KMSAN: uninit-value in __list_add_valid+0x286/0x420 lib/list_debug.c:26
CPU: 1 PID: 2021 Comm: kswapd0 Not tainted 5.12.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x24c/0x2e0 lib/dump_stack.c:120
 kmsan_report+0xfb/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x5c/0xa0 mm/kmsan/kmsan_instr.c:197
 __list_add_valid+0x286/0x420 lib/list_debug.c:26
 __list_add include/linux/list.h:67 [inline]
 list_add_tail include/linux/list.h:100 [inline]
 rwsem_down_read_slowpath kernel/locking/rwsem.c:955 [inline]
 __down_read_common+0x4f4/0x1270 kernel/locking/rwsem.c:1213
 __down_read kernel/locking/rwsem.c:1222 [inline]
 down_read+0x2b/0x30 kernel/locking/rwsem.c:1355
 anon_vma_lock_read include/linux/rmap.h:129 [inline]
 page_lock_anon_vma_read+0x3d6/0x610 mm/rmap.c:570
 rmap_walk_anon_lock mm/rmap.c:1823 [inline]
 rmap_walk_anon+0x112/0x1290 mm/rmap.c:1865
 rmap_walk mm/rmap.c:1952 [inline]
 page_referenced+0xaca/0xc30 mm/rmap.c:895
 page_check_references mm/vmscan.c:991 [inline]
 shrink_page_list+0x1dd1/0x7840 mm/vmscan.c:1220
 shrink_inactive_list+0x83f/0x14f0 mm/vmscan.c:1948
 shrink_list mm/vmscan.c:2170 [inline]
 shrink_lruvec+0x738/0x1480 mm/vmscan.c:2465
 shrink_node_memcgs+0x5a3/0xc60 mm/vmscan.c:2653
 shrink_node+0x1a02/0x3400 mm/vmscan.c:2770
 kswapd_shrink_node mm/vmscan.c:3513 [inline]
 balance_pgdat+0x146e/0x2570 mm/vmscan.c:3671
 kswapd+0x50b/0x8a0 mm/vmscan.c:3928
 kthread+0x521/0x560 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Local variable ----pvmw@remove_migration_pte created at:
 remove_migration_pte+0xbe/0x1920 mm/migrate.c:204
 remove_migration_pte+0xbe/0x1920 mm/migrate.c:204
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