loop2: detected capacity change from 0 to 224
==================================================================
BUG: KCSAN: data-race in __lru_add_drain_all / lru_cache_add_inactive_or_unevictable

write to 0xffff888237d22528 of 1 bytes by task 10762 on cpu 1:
 pagevec_add include/linux/pagevec.h:74 [inline]
 pagevec_add_and_need_flush mm/swap.c:222 [inline]
 lru_cache_add mm/swap.c:452 [inline]
 lru_cache_add_inactive_or_unevictable+0xaa/0x270 mm/swap.c:484
 do_anonymous_page+0x716/0x8b0 mm/memory.c:3807
 handle_pte_fault mm/memory.c:4556 [inline]
 __handle_mm_fault mm/memory.c:4693 [inline]
 handle_mm_fault+0x7f5/0x1580 mm/memory.c:4791
 do_user_addr_fault+0x609/0xbe0 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x91/0x220 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30
 __clear_user arch/x86/lib/usercopy_64.c:24 [inline]
 clear_user+0x60/0xa0 arch/x86/lib/usercopy_64.c:54
 iov_iter_zero+0x11b/0xb20 lib/iov_iter.c:900
 read_iter_zero+0x63/0x180 drivers/char/mem.c:492
 call_read_iter include/linux/fs.h:2157 [inline]
 do_iter_readv_writev+0x2fb/0x380 fs/read_write.c:727
 do_iter_read+0x192/0x5d0 fs/read_write.c:790
 vfs_readv fs/read_write.c:910 [inline]
 do_readv+0x16e/0x2c0 fs/read_write.c:947
 __do_sys_readv fs/read_write.c:1038 [inline]
 __se_sys_readv fs/read_write.c:1035 [inline]
 __x64_sys_readv+0x41/0x50 fs/read_write.c:1035
 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 0xffff888237d22528 of 1 bytes by task 10780 on cpu 0:
 pagevec_count include/linux/pagevec.h:61 [inline]
 __lru_add_drain_all+0x12c/0x3e0 mm/swap.c:806
 lru_add_drain_all+0xc/0x10 mm/swap.c:828
 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:477
 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: 0x03 -> 0x04

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10780 Comm: syz-executor.2 Tainted: G        W         5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================