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BUG: KCSAN: data-race in ext4_mark_iloc_dirty / generic_update_time

read to 0xffff88812574d2d0 of 8 bytes by task 8437 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:4929 [inline]
 ext4_mark_iloc_dirty+0x44a/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
 generic_update_time+0x184/0x270 fs/inode.c:1667
 update_time fs/inode.c:1683 [inline]
 touch_atime+0x172/0x190 fs/inode.c:1754
 file_accessed include/linux/fs.h:2209 [inline]
 ext4_dio_read_iter fs/ext4/file.c:81 [inline]
 ext4_file_read_iter fs/ext4/file.c:128 [inline]
 ext4_file_read_iter+0x22b/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

write to 0xffff88812574d2d0 of 16 bytes by task 8438 on cpu 1:
 generic_update_time+0x109/0x270 fs/inode.c:1660
 update_time fs/inode.c:1683 [inline]
 file_update_time+0x237/0x300 fs/inode.c:1898
 file_modified fs/inode.c:1921 [inline]
 file_modified+0x65/0x80 fs/inode.c:1906
 ext4_write_checks fs/ext4/file.c:230 [inline]
 ext4_write_checks+0x155/0x1b0 fs/ext4/file.c:206
 ext4_dio_write_iter fs/ext4/file.c:391 [inline]
 ext4_file_write_iter+0x1a7/0xd40 fs/ext4/file.c:545
 call_write_iter include/linux/fs.h:1902 [inline]
 do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x13b/0x3c0 fs/read_write.c:951
 vfs_iter_write+0x5c/0x80 fs/read_write.c:983
 iter_file_splice_write+0x530/0x840 fs/splice.c:760
 do_splice_from fs/splice.c:863 [inline]
 direct_splice_actor+0xa0/0xc0 fs/splice.c:1037
 splice_direct_to_actor+0x22b/0x540 fs/splice.c:992
 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:1519 [inline]
 __se_sys_sendfile64 fs/read_write.c:1511 [inline]
 __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511
 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: 1 PID: 8438 Comm: syz-executor.5 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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