==================================================================
BUG: KCSAN: data-race in ion_page_pool_remove / ion_page_pool_shrink

write to 0xffff888218107384 of 4 bytes by task 1791 on cpu 0:
 ion_page_pool_remove+0xcd/0x200 drivers/staging/android/ion/ion_page_pool.c:55
 ion_page_pool_shrink+0x189/0x250 drivers/staging/android/ion/ion_page_pool.c:119
 ion_system_heap_shrink+0xb4/0xd0 drivers/staging/android/ion/ion_system_heap.c:194
 ion_heap_shrink_scan+0xc6/0x120 drivers/staging/android/ion/ion_heap.c:302
 do_shrink_slab+0x2a9/0x5b0 mm/vmscan.c:512
 shrink_slab mm/vmscan.c:673 [inline]
 shrink_slab+0x153/0x540 mm/vmscan.c:646
 shrink_node_memcgs mm/vmscan.c:2673 [inline]
 shrink_node+0x354/0x1000 mm/vmscan.c:2777
 kswapd_shrink_node mm/vmscan.c:3523 [inline]
 balance_pgdat+0x641/0xd00 mm/vmscan.c:3681
 kswapd+0x35d/0x800 mm/vmscan.c:3932
 kthread+0x1cb/0x1f0 kernel/kthread.c:255
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

read to 0xffff888218107384 of 4 bytes by task 9644 on cpu 1:
 ion_page_pool_total drivers/staging/android/ion/ion_page_pool.c:92 [inline]
 ion_page_pool_shrink+0x1b5/0x250 drivers/staging/android/ion/ion_page_pool.c:112
 ion_system_heap_shrink+0x64/0xd0 drivers/staging/android/ion/ion_system_heap.c:189
 ion_heap_shrink_count+0x80/0xa0 drivers/staging/android/ion/ion_heap.c:273
 do_shrink_slab+0xb3/0x5b0 mm/vmscan.c:430
 shrink_slab mm/vmscan.c:673 [inline]
 shrink_slab+0x153/0x540 mm/vmscan.c:646
 shrink_node_memcgs mm/vmscan.c:2673 [inline]
 shrink_node+0x354/0x1000 mm/vmscan.c:2777
 shrink_zones mm/vmscan.c:2980 [inline]
 do_try_to_free_pages+0x230/0xb30 mm/vmscan.c:3033
 try_to_free_pages+0x1e6/0x470 mm/vmscan.c:3272
 __perform_reclaim mm/page_alloc.c:4113 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4134 [inline]
 __alloc_pages_slowpath+0x3cc/0xda0 mm/page_alloc.c:4537
 __alloc_pages_nodemask+0x2c5/0x310 mm/page_alloc.c:4751
 __alloc_pages include/linux/gfp.h:496 [inline]
 __alloc_pages_node include/linux/gfp.h:509 [inline]
 kmem_getpages mm/slab.c:1367 [inline]
 cache_grow_begin+0x1f1/0x590 mm/slab.c:2600
 fallback_alloc+0x167/0x1f0 mm/slab.c:3147
 slab_alloc_node mm/slab.c:3255 [inline]
 kmem_cache_alloc_node_trace+0xb5/0x610 mm/slab.c:3597
 kmalloc_node include/linux/slab.h:578 [inline]
 kvmalloc_node+0xc3/0x100 mm/util.c:574
 kvmalloc include/linux/mm.h:645 [inline]
 kvzalloc include/linux/mm.h:653 [inline]
 netif_alloc_rx_queues net/core/dev.c:9147 [inline]
 alloc_netdev_mqs+0x5ee/0x870 net/core/dev.c:9850
 tun_set_iff drivers/net/tun.c:2789 [inline]
 __tun_chr_ioctl+0x193b/0x25d0 drivers/net/tun.c:3086
 tun_chr_ioctl+0x2e/0x40 drivers/net/tun.c:3366
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x101/0x150 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x47/0x60 fs/ioctl.c:770
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9644 Comm: syz-executor.2 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================