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BUG: KCSAN: data-race in __jbd2_journal_drop_transaction / start_this_handle

write to 0xffff888102aa2078 of 8 bytes by task 19625 on cpu 0:
 jbd2_get_transaction fs/jbd2/transaction.c:125 [inline]
 start_this_handle+0xd37/0x1050 fs/jbd2/transaction.c:416
 jbd2__journal_start+0x1fc/0x3f0 fs/jbd2/transaction.c:525
 __ext4_journal_start_sb+0x159/0x310 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x58/0xa0 fs/ext4/inode.c:5905
 __mark_inode_dirty+0x72/0x6c0 fs/fs-writeback.c:2399
 generic_update_time fs/inode.c:1776 [inline]
 inode_update_time+0x1b4/0x1d0 fs/inode.c:1789
 file_update_time+0x1f3/0x230 fs/inode.c:2006
 file_modified+0x62/0x80 fs/inode.c:2029
 ext4_dio_write_checks fs/ext4/file.c:458 [inline]
 ext4_dio_write_iter fs/ext4/file.c:522 [inline]
 ext4_file_write_iter+0x795/0x1200 fs/ext4/file.c:679
 call_write_iter include/linux/fs.h:2161 [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+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888102aa2078 of 8 bytes by task 346 on cpu 1:
 __jbd2_journal_drop_transaction+0x1f0/0x2f0 fs/jbd2/checkpoint.c:803
 __jbd2_journal_remove_checkpoint+0x2d5/0x3a0 fs/jbd2/checkpoint.c:734
 jbd2_journal_commit_transaction+0x23f1/0x3460 fs/jbd2/commit.c:1019
 kjournald2+0x263/0x480 fs/jbd2/journal.c:213
 kthread+0x2c7/0x2e0 kernel/kthread.c:327
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000000000 -> 0xffff888136dae500

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 346 Comm: jbd2/sda1-8 Tainted: G        W         5.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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