syzbot

==================================================================
BUG: KCSAN: data-race in __es_shrink / __es_shrink

read to 0xffff888126417c78 of 8 bytes by task 17142 on cpu 1:
 __es_shrink+0x328/0x610 fs/ext4/extents_status.c:1515
 ext4_es_scan+0x1ce/0x2d0 fs/ext4/extents_status.c:1559
 do_shrink_slab+0x2b6/0x5a0 mm/vmscan.c:560
 shrink_slab mm/vmscan.c:721 [inline]
 shrink_slab+0x147/0x540 mm/vmscan.c:694
 shrink_node+0x1ad/0xb30 mm/vmscan.c:2813
 shrink_zones mm/vmscan.c:3027 [inline]
 do_try_to_free_pages+0x242/0x940 mm/vmscan.c:3085
 try_to_free_pages+0x1ed/0x4a0 mm/vmscan.c:3298
 __perform_reclaim mm/page_alloc.c:4121 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4142 [inline]
 __alloc_pages_slowpath+0x45c/0xee0 mm/page_alloc.c:4559
 __alloc_pages_nodemask+0x2c8/0x310 mm/page_alloc.c:4773
 alloc_pages_vma+0xc1/0x3a0 mm/mempolicy.c:2151
 alloc_zeroed_user_highpage_movable include/linux/highmem.h:208 [inline]
 do_anonymous_page mm/memory.c:3002 [inline]
 handle_pte_fault mm/memory.c:3847 [inline]
 __handle_mm_fault+0x175b/0x2cb0 mm/memory.c:3973
 handle_mm_fault+0x21b/0x530 mm/memory.c:4010
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x3fb/0x9e0 arch/x86/mm/fault.c:1506
 do_page_fault+0x54/0x233 arch/x86/mm/fault.c:1530

write to 0xffff888126417c78 of 8 bytes by task 16837 on cpu 0:
 __es_shrink+0x35f/0x610 fs/ext4/extents_status.c:1517
 ext4_es_scan+0x1ce/0x2d0 fs/ext4/extents_status.c:1559
 do_shrink_slab+0x2b6/0x5a0 mm/vmscan.c:560
 shrink_slab mm/vmscan.c:721 [inline]
 shrink_slab+0x147/0x540 mm/vmscan.c:694
 shrink_node+0x1ad/0xb30 mm/vmscan.c:2813
 shrink_zones mm/vmscan.c:3027 [inline]
 do_try_to_free_pages+0x242/0x940 mm/vmscan.c:3085
 try_to_free_pages+0x1ed/0x4a0 mm/vmscan.c:3298
 __perform_reclaim mm/page_alloc.c:4121 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4142 [inline]
 __alloc_pages_slowpath+0x45c/0xee0 mm/page_alloc.c:4559
 __alloc_pages_nodemask+0x2c8/0x310 mm/page_alloc.c:4773
 alloc_pages_vma+0xc1/0x3a0 mm/mempolicy.c:2151
 alloc_zeroed_user_highpage_movable include/linux/highmem.h:208 [inline]
 do_anonymous_page mm/memory.c:3002 [inline]
 handle_pte_fault mm/memory.c:3847 [inline]
 __handle_mm_fault+0x175b/0x2cb0 mm/memory.c:3973
 handle_mm_fault+0x21b/0x530 mm/memory.c:4010
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x3fb/0x9e0 arch/x86/mm/fault.c:1506

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 16837 Comm: blkid Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================