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BUG: KCSAN: data-race in lru_add_drain_all / lru_cache_add_inactive_or_unevictable

write to 0xffff888237c264a8 of 1 bytes by task 19672 on cpu 0:
 pagevec_add include/linux/pagevec.h:74 [inline]
 lru_cache_add mm/swap.c:461 [inline]
 lru_cache_add_inactive_or_unevictable+0xa9/0x250 mm/swap.c:493
 do_anonymous_page+0x709/0x8b0 mm/memory.c:3587
 handle_pte_fault mm/memory.c:4316 [inline]
 __handle_mm_fault mm/memory.c:4453 [inline]
 handle_mm_fault+0x96f/0x1a70 mm/memory.c:4551
 faultin_page mm/gup.c:850 [inline]
 __get_user_pages+0x947/0xee0 mm/gup.c:1069
 __get_user_pages_locked mm/gup.c:1255 [inline]
 __get_user_pages_remote+0x18e/0x600 mm/gup.c:1726
 get_user_pages_remote+0x6f/0xa0 mm/gup.c:1799
 get_arg_page fs/exec.c:223 [inline]
 copy_string_kernel+0x16f/0x380 fs/exec.c:634
 kernel_execve+0x397/0x640 fs/exec.c:1960
 call_usermodehelper_exec_async+0x1d3/0x290 kernel/umh.c:110
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff888237c264a8 of 1 bytes by task 19654 on cpu 1:
 pagevec_count include/linux/pagevec.h:61 [inline]
 lru_add_drain_all+0x108/0x3c0 mm/swap.c:813
 invalidate_bdev+0x50/0x70 fs/block_dev.c:96
 __loop_clr_fd+0x2e2/0x650 drivers/block/loop.c:1241
 loop_clr_fd drivers/block/loop.c:1336 [inline]
 lo_ioctl+0x9eb/0x11f0 drivers/block/loop.c:1694
 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585
 block_ioctl+0x6d/0x80 fs/block_dev.c:1671
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:1069 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19654 Comm: syz-executor.2 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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