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BUG: KCSAN: data-race in start_this_handle / start_this_handle

write to 0xffff888144614070 of 8 bytes by task 9939 on cpu 1:
 jbd2_get_transaction fs/jbd2/transaction.c:125 [inline]
 start_this_handle+0xceb/0x1010 fs/jbd2/transaction.c:400
 jbd2__journal_start+0x1fc/0x3f0 fs/jbd2/transaction.c:503
 __ext4_journal_start_sb+0x159/0x310 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:320 [inline]
 ext4_da_write_begin+0x460/0xaf0 fs/ext4/inode.c:2997
 generic_perform_write+0x196/0x3a0 mm/filemap.c:3503
 ext4_buffered_write_iter+0x2e5/0x3e0 fs/ext4/file.c:269
 ext4_file_write_iter+0x48a/0x10b0 fs/ext4/file.c:502
 call_write_iter include/linux/fs.h:1901 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 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+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x7a6/0xe20 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1319 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888144614070 of 8 bytes by task 8371 on cpu 0:
 start_this_handle+0x1c1/0x1010 fs/jbd2/transaction.c:352
 jbd2__journal_start+0x1fc/0x3f0 fs/jbd2/transaction.c:503
 __ext4_journal_start_sb+0x159/0x310 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:320 [inline]
 ext4_dirty_inode+0x78/0xc0 fs/ext4/inode.c:5951
 __mark_inode_dirty+0x72/0x6b0 fs/fs-writeback.c:2262
 generic_update_time fs/inode.c:1763 [inline]
 update_time fs/inode.c:1776 [inline]
 touch_atime+0x1b1/0x2d0 fs/inode.c:1847
 file_accessed include/linux/fs.h:2218 [inline]
 iterate_dir+0x31b/0x370 fs/readdir.c:70
 __do_sys_getdents64 fs/readdir.c:366 [inline]
 __se_sys_getdents64+0x7f/0x190 fs/readdir.c:351
 __x64_sys_getdents64+0x3f/0x50 fs/readdir.c:351
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8371 Comm: syz-executor.2 Not tainted 5.11.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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