syzbot

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BUG: KCSAN: data-race in __jbd2_journal_drop_transaction / start_this_handle

write to 0xffff888103e9d078 of 8 bytes by task 1819 on cpu 0:
 jbd2_get_transaction fs/jbd2/transaction.c:124 [inline]
 start_this_handle+0xd80/0x1130 fs/jbd2/transaction.c:411
 jbd2__journal_start+0x1d1/0x3b0 fs/jbd2/transaction.c:520
 __ext4_journal_start_sb+0x159/0x300 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_unlink+0x1b5/0x3b0 fs/ext4/namei.c:3224
 vfs_unlink+0x246/0x3d0 fs/namei.c:4148
 do_unlinkat+0x258/0x510 fs/namei.c:4216
 __do_sys_unlink fs/namei.c:4264 [inline]
 __se_sys_unlink fs/namei.c:4262 [inline]
 __x64_sys_unlink+0x2c/0x30 fs/namei.c:4262
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888103e9d078 of 8 bytes by task 1404 on cpu 1:
 __jbd2_journal_drop_transaction+0x1f0/0x2f0 fs/jbd2/checkpoint.c:803
 __jbd2_journal_remove_checkpoint+0x2cd/0x3a0 fs/jbd2/checkpoint.c:734
 jbd2_journal_commit_transaction+0x235c/0x3180 fs/jbd2/commit.c:1008
 kjournald2+0x253/0x460 fs/jbd2/journal.c:213
 kthread+0x1a9/0x1e0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30

value changed: 0x0000000000000000 -> 0xffff888135e18400

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 1404 Comm: jbd2/sda1-8 Tainted: G        W         5.18.0-rc6-syzkaller-00007-g9be9ed2612b5 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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