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BUG: KCSAN: data-race in __ext4_journal_start_sb / jbd2_journal_commit_transaction

write to 0xffff888144850800 of 8 bytes by task 4854 on cpu 0:
 jbd2_journal_commit_transaction+0x238/0x32b0 fs/jbd2/commit.c:443
 kjournald2+0x263/0x480 fs/jbd2/journal.c:213
 kthread+0x20b/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296

read to 0xffff888144850800 of 8 bytes by task 11935 on cpu 1:
 is_journal_aborted include/linux/jbd2.h:1647 [inline]
 ext4_journal_check_start fs/ext4/ext4_jbd2.c:82 [inline]
 __ext4_journal_start_sb+0xed/0x310 fs/ext4/ext4_jbd2.c:98
 __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
 mark_inode_dirty include/linux/fs.h:2181 [inline]
 generic_write_end+0x166/0x240 fs/buffer.c:2202
 ext4_da_write_end+0x59b/0x760 fs/ext4/inode.c:3111
 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3419
 ext4_buffered_write_iter+0x2e5/0x3e0 fs/ext4/file.c:270
 ext4_file_write_iter+0x47a/0x1060 fs/ext4/file.c:503
 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+0x41a/0x770 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:933
 splice_direct_to_actor+0x345/0x650 fs/splice.c:888
 do_splice_direct+0xf5/0x170 fs/splice.c:976
 do_sendfile+0x5e0/0xcf0 fs/read_write.c:1257
 __do_sys_sendfile64 fs/read_write.c:1312 [inline]
 __se_sys_sendfile64 fs/read_write.c:1304 [inline]
 __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1304
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11935 Comm: syz-executor.0 Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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