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BUG: KCSAN: data-race in ext4_mark_iloc_dirty / generic_update_time

write to 0xffff8881252135c0 of 16 bytes by task 8255 on cpu 1:
 generic_update_time+0x5c/0x270 fs/inode.c:1654
 update_time fs/inode.c:1683 [inline]
 touch_atime+0x172/0x190 fs/inode.c:1754
 file_accessed include/linux/fs.h:2209 [inline]
 generic_file_buffered_read mm/filemap.c:2258 [inline]
 generic_file_read_iter+0x116e/0x1440 mm/filemap.c:2324
 ext4_file_read_iter fs/ext4/file.c:130 [inline]
 ext4_file_read_iter+0x10c/0x380 fs/ext4/file.c:113
 call_read_iter include/linux/fs.h:1896 [inline]
 generic_file_splice_read+0x35c/0x500 fs/splice.c:313
 do_splice_to+0xf2/0x130 fs/splice.c:892
 splice_direct_to_actor+0x1b6/0x540 fs/splice.c:971
 do_splice_direct+0x161/0x1e0 fs/splice.c:1080
 do_sendfile+0x384/0x7f0 fs/read_write.c:1464
 __do_sys_sendfile64 fs/read_write.c:1525 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0x12a/0x140 fs/read_write.c:1511
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8881252135c0 of 8 bytes by task 8240 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:4930 [inline]
 ext4_mark_iloc_dirty+0x523/0x1580 fs/ext4/inode.c:5547
 ext4_mark_inode_dirty+0xe9/0x420 fs/ext4/inode.c:5740
 ext4_dirty_inode+0xb1/0xe0 fs/ext4/inode.c:5771
 __mark_inode_dirty+0x5d4/0x940 fs/fs-writeback.c:2258
 mark_inode_dirty include/linux/fs.h:2172 [inline]
 generic_write_end+0x1b7/0x1f0 fs/buffer.c:2199
 ext4_da_write_end+0x158/0x620 fs/ext4/inode.c:3091
 generic_perform_write+0x1d3/0x320 mm/filemap.c:3320
 ext4_buffered_write_iter+0x143/0x290 fs/ext4/file.c:252
 ext4_file_write_iter+0xf4/0xd40 fs/ext4/file.c:547
 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: 8240 Comm: syz-executor.4 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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