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BUG: KCSAN: data-race in lru_add_drain_all / lru_cache_add

write to 0xffff888237c264a8 of 1 bytes by task 25610 on cpu 0:
 pagevec_add include/linux/pagevec.h:74 [inline]
 lru_cache_add+0x74/0x130 mm/swap.c:461
 add_to_page_cache_lru+0x150/0x1b0 mm/filemap.c:956
 page_cache_ra_unbounded+0x262/0x410 mm/readahead.c:221
 do_page_cache_ra mm/readahead.c:267 [inline]
 force_page_cache_ra+0x246/0x280 mm/readahead.c:299
 page_cache_sync_ra+0xcc/0xe0 mm/readahead.c:573
 page_cache_sync_readahead include/linux/pagemap.h:864 [inline]
 filemap_get_pages mm/filemap.c:2442 [inline]
 filemap_read+0x388/0x1230 mm/filemap.c:2525
 generic_file_read_iter+0x84/0x3e0 mm/filemap.c:2676
 blkdev_read_iter+0xb3/0xc0 fs/block_dev.c:1720
 call_read_iter include/linux/fs.h:2110 [inline]
 new_sync_read fs/read_write.c:415 [inline]
 vfs_read+0x565/0x5d0 fs/read_write.c:496
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888237c264a8 of 1 bytes by task 1760 on cpu 1:
 pagevec_count include/linux/pagevec.h:61 [inline]
 lru_add_drain_all+0x108/0x3b0 mm/swap.c:813
 invalidate_bdev+0x50/0x70 fs/block_dev.c:96
 ext4_put_super+0x5d0/0x8e0 fs/ext4/super.c:1229
 generic_shutdown_super+0xd5/0x220 fs/super.c:464
 kill_block_super+0x4a/0x90 fs/super.c:1394
 deactivate_locked_super+0x65/0xd0 fs/super.c:335
 deactivate_super+0x85/0x90 fs/super.c:366
 cleanup_mnt+0x267/0x2d0 fs/namespace.c:1136
 __cleanup_mnt+0x15/0x20 fs/namespace.c:1143
 task_work_run+0xae/0x130 kernel/task_work.c:161
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1760 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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