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BUG: KCSAN: data-race in __lru_add_drain_all / lru_cache_add

write to 0xffff888237c22528 of 1 bytes by task 1127 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_getpage mm/shmem.c:151 [inline]
 shmem_file_read_iter+0x1b2/0x5d0 mm/shmem.c:2546
 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_iter_read+0x4c/0x70 fs/read_write.c:832
 lo_read_simple drivers/block/loop.c:404 [inline]
 do_req_filebacked drivers/block/loop.c:675 [inline]
 loop_handle_cmd drivers/block/loop.c:2201 [inline]
 loop_process_work+0x11ae/0x18f0 drivers/block/loop.c:2241
 loop_rootcg_workfn+0x1b/0x20 drivers/block/loop.c:2272
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff888237c22528 of 1 bytes by task 7385 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: 0x0b -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7385 Comm: syz-executor.1 Not tainted 5.15.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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