syzbot

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BUG: KCSAN: data-race in ext4_alloc_da_blocks / ext4_da_reserve_space

write to 0xffff88813748dcc8 of 4 bytes by task 10111 on cpu 1:
 ext4_da_reserve_space+0x12b/0x1f0 fs/ext4/inode.c:1478
 ext4_insert_delayed_block fs/ext4/inode.c:1645 [inline]
 ext4_da_map_blocks fs/ext4/inode.c:1763 [inline]
 ext4_da_get_block_prep+0x513/0x9e0 fs/ext4/inode.c:1827
 __block_write_begin_int+0x4c5/0x1010 fs/buffer.c:2010
 __block_write_begin+0x2b/0x40 fs/buffer.c:2060
 ext4_da_write_begin+0x34e/0x590 fs/ext4/inode.c:2969
 generic_perform_write+0x1c8/0x400 mm/filemap.c:3756
 ext4_buffered_write_iter+0x25b/0x380 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x1200
 call_write_iter include/linux/fs.h:2162 [inline]
 do_iter_readv_writev+0x2de/0x380 fs/read_write.c:725
 do_iter_write+0x192/0x5c0 fs/read_write.c:851
 vfs_iter_write+0x4c/0x70 fs/read_write.c:892
 iter_file_splice_write+0x43a/0x790 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0x106/0x190 fs/splice.c:979
 do_sendfile+0x675/0xc40 fs/read_write.c:1245
 __do_sys_sendfile64 fs/read_write.c:1310 [inline]
 __se_sys_sendfile64 fs/read_write.c:1296 [inline]
 __x64_sys_sendfile64+0x102/0x140 fs/read_write.c:1296
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813748dcc8 of 4 bytes by task 10110 on cpu 0:
 ext4_alloc_da_blocks+0x1a/0x100 fs/ext4/inode.c:3069
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000189b -> 0x0000189c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10110 Comm: syz-executor.5 Not tainted 5.16.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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