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BUG: KCSAN: data-race in iomap_dio_bio_actor / iomap_dio_bio_end_io

read to 0xffff8880a61302a4 of 4 bytes by interrupt on cpu 1:
 iomap_dio_bio_end_io+0x4c/0x2b0 fs/iomap/direct-io.c:149
 bio_endio+0x2fa/0x400 block/bio.c:1821
 req_bio_endio block/blk-core.c:245 [inline]
 blk_update_request+0x427/0x7b0 block/blk-core.c:1464
 scsi_end_request+0x6b/0x360 drivers/scsi/scsi_lib.c:576
 scsi_io_completion+0x11d/0xc80 drivers/scsi/scsi_lib.c:960
 scsi_finish_command+0x283/0x380 drivers/scsi/scsi.c:228
 scsi_softirq_done+0x259/0x280 drivers/scsi/scsi_lib.c:1476
 blk_done_softirq+0x1eb/0x250 block/blk-softirq.c:37
 __do_softirq+0x115/0x33f kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0xbb/0xe0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 do_IRQ+0x81/0x130 arch/x86/kernel/irq.c:263
 ret_from_intr+0x0/0x21
 __read_once_size include/linux/compiler.h:232 [inline]
 arch_atomic64_read arch/x86/include/asm/atomic64_64.h:22 [inline]
 atomic64_read include/asm-generic/atomic-instrumented.h:851 [inline]
 atomic_long_read include/asm-generic/atomic-long.h:29 [inline]
 find_watchpoint kernel/kcsan/core.c:96 [inline]
 check_access kernel/kcsan/core.c:446 [inline]
 __tsan_read4+0x34/0x100 kernel/kcsan/core.c:588
 __rcu_read_unlock+0xb8/0x3d0 kernel/rcu/tree_plugin.h:382
 rcu_read_unlock include/linux/rcupdate.h:670 [inline]
 dput+0xa1/0x750 fs/dcache.c:847
 path_to_nameidata fs/namei.c:830 [inline]
 step_into fs/namei.c:1768 [inline]
 walk_component+0x2e4/0xd90 fs/namei.c:1816
 link_path_walk.part.0+0x5d3/0xa90 fs/namei.c:2128
 link_path_walk fs/namei.c:2256 [inline]
 path_lookupat.isra.0+0x77/0x5a0 fs/namei.c:2304
 filename_lookup+0x145/0x2b0 fs/namei.c:2335
 user_path_at_empty+0x4c/0x70 fs/namei.c:2615
 user_path_at include/linux/namei.h:49 [inline]
 vfs_statx+0xd9/0x190 fs/stat.c:187
 vfs_stat include/linux/fs.h:3249 [inline]
 __do_sys_newstat+0x51/0xb0 fs/stat.c:341
 __se_sys_newstat fs/stat.c:337 [inline]
 __x64_sys_newstat+0x3a/0x50 fs/stat.c:337
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880a61302a4 of 4 bytes by task 18282 on cpu 0:
 iomap_dio_bio_actor+0x6dc/0x960 fs/iomap/direct-io.c:293
 iomap_dio_actor+0x87/0x3a0 fs/iomap/direct-io.c:382
 iomap_apply+0x20d/0x6a0 fs/iomap/apply.c:80
 iomap_dio_rw+0x67e/0x9a0 fs/iomap/direct-io.c:498
 ext4_dio_write_iter fs/ext4/file.c:438 [inline]
 ext4_file_write_iter+0xc38/0xd40 fs/ext4/file.c:545
 call_write_iter include/linux/fs.h:1902 [inline]
 new_sync_write+0x388/0x4a0 fs/read_write.c:483
 __vfs_write+0xb1/0xc0 fs/read_write.c:496
 vfs_write fs/read_write.c:558 [inline]
 vfs_write+0x18a/0x390 fs/read_write.c:542
 ksys_write+0xd5/0x1b0 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write fs/read_write.c:620 [inline]
 __x64_sys_write+0x4c/0x60 fs/read_write.c:620
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 18282 Comm: syz-executor.0 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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