loop5: detected capacity change from 0 to 264192
EXT4-fs (loop5): VFS: Found ext4 filesystem with invalid superblock checksum.  Run e2fsck?
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BUG: KCSAN: data-race in kthread_is_per_cpu / page_cache_ra_unbounded

write to 0xffff88812d49202c of 4 bytes by task 5203 on cpu 1:
 memalloc_nofs_save include/linux/sched/mm.h:245 [inline]
 page_cache_ra_unbounded+0xa8/0x410 mm/readahead.c:193
 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:874 [inline]
 filemap_get_pages mm/filemap.c:2483 [inline]
 filemap_read+0x388/0x1230 mm/filemap.c:2566
 generic_file_read_iter+0x75/0x2c0 mm/filemap.c:2717
 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 0xffff88812d49202c of 4 bytes by task 5280 on cpu 0:
 __to_kthread kernel/kthread.c:101 [inline]
 kthread_is_per_cpu+0x2d/0x80 kernel/kthread.c:540
 can_migrate_task+0xf/0x180 kernel/sched/fair.c:7615
 detach_tasks+0xab/0x380 kernel/sched/fair.c:7779
 load_balance+0x768/0xcc0 kernel/sched/fair.c:9679
 newidle_balance+0x10b/0x310 kernel/sched/fair.c:10643
 pick_next_task_fair+0x37/0x270 kernel/sched/fair.c:7203
 pick_next_task kernel/sched/core.c:4960 [inline]
 __schedule+0x256/0x5b0 kernel/sched/core.c:5111
 schedule+0x67/0x90 kernel/sched/core.c:5226
 schedule_preempt_disabled+0x5/0x10 kernel/sched/core.c:5285
 __mutex_lock_common kernel/locking/mutex.c:1026 [inline]
 __mutex_lock+0x3cb/0x670 kernel/locking/mutex.c:1096
 __mutex_lock_killable_slowpath+0xa/0x10 kernel/locking/mutex.c:1363
 mutex_lock_killable+0x25/0x30 kernel/locking/mutex.c:1330
 lo_open+0x1a/0xd0 drivers/block/loop.c:1889
 __blkdev_get+0x149/0x6c0 fs/block_dev.c:1349
 blkdev_get_by_dev+0x9b/0x480 fs/block_dev.c:1453
 blkdev_open+0xb3/0x130 fs/block_dev.c:1548
 do_dentry_open+0x53e/0x830 fs/open.c:826
 vfs_open+0x43/0x50 fs/open.c:940
 do_open fs/namei.c:3361 [inline]
 path_openat+0x184e/0x20b0 fs/namei.c:3494
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_openat fs/open.c:1219 [inline]
 __se_sys_openat fs/open.c:1214 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1214
 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: 0 PID: 5280 Comm: syz-executor.5 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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