==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / lru_cache_add

write to 0xffff888237c22528 of 1 bytes by task 30115 on cpu 0:
 pagevec_add include/linux/pagevec.h:74 [inline]
 pagevec_add_and_need_flush mm/swap.c:222 [inline]
 lru_cache_add+0x75/0x150 mm/swap.c:452
 shmem_getpage_gfp+0xcb9/0x13d0 mm/shmem.c:1940
 shmem_fault+0xcf/0x470 mm/shmem.c:2113
 __do_fault mm/memory.c:3858 [inline]
 do_read_fault mm/memory.c:4182 [inline]
 do_fault mm/memory.c:4310 [inline]
 handle_pte_fault mm/memory.c:4568 [inline]
 __handle_mm_fault mm/memory.c:4703 [inline]
 handle_mm_fault+0xbb7/0x1580 mm/memory.c:4801
 faultin_page mm/gup.c:937 [inline]
 __get_user_pages+0x381/0xc50 mm/gup.c:1158
 populate_vma_page_range mm/gup.c:1490 [inline]
 __mm_populate+0x24d/0x370 mm/gup.c:1599
 mm_populate include/linux/mm.h:2624 [inline]
 __do_sys_remap_file_pages+0x39c/0x590 mm/mmap.c:3011
 __se_sys_remap_file_pages mm/mmap.c:2940 [inline]
 __x64_sys_remap_file_pages+0x63/0x70 mm/mmap.c:2940
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c22528 of 1 bytes by task 30003 on cpu 1:
 pagevec_count include/linux/pagevec.h:61 [inline]
 __lru_add_drain_all+0x12c/0x3e0 mm/swap.c:819
 lru_add_drain_all+0xc/0x10 mm/swap.c:841
 invalidate_bdev+0x56/0x80 block/bdev.c:87
 __loop_clr_fd+0x521/0x850 drivers/block/loop.c:1399
 loop_clr_fd drivers/block/loop.c:1494 [inline]
 lo_ioctl+0xac5/0x13e0 drivers/block/loop.c:1850
 blkdev_ioctl+0x1d0/0x3f0 block/ioctl.c:589
 block_ioctl+0x6e/0x80 block/fops.c:478
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:860
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x06 -> 0x09

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 30003 Comm: syz-executor.4 Not tainted 5.15.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
loop4: detected capacity change from 0 to 1
FAT-fs (loop4): bogus logical sector size 65295
FAT-fs (loop4): Can't find a valid FAT filesystem