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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_sb_inodes

write to 0xffff8881059d07d0 of 8 bytes by task 1764 on cpu 0:
 writeback_sb_inodes+0x3cc/0xf10 fs/fs-writeback.c:1721
 wb_writeback+0x28e/0x700 fs/fs-writeback.c:1905
 wb_do_writeback+0x101/0x510 fs/fs-writeback.c:2050
 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2091
 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2275
 worker_thread+0x636/0xae0 kernel/workqueue.c:2421
 kthread+0x1d0/0x1f0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff8881059d07d0 of 8 bytes by task 7482 on cpu 1:
 __mark_inode_dirty+0xda/0x6c0 fs/fs-writeback.c:2295
 mark_inode_dirty_sync include/linux/fs.h:2272 [inline]
 dquot_free_space include/linux/quotaops.h:382 [inline]
 dquot_free_block include/linux/quotaops.h:392 [inline]
 ext4_mb_new_blocks+0x1696/0x1f60 fs/ext4/mballoc.c:5030
 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4238
 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638
 ext4_alloc_file_blocks+0x271/0x720 fs/ext4/extents.c:4425
 ext4_zero_range+0x309/0xa40 fs/ext4/extents.c:4537
 ext4_fallocate+0x226/0x4d0 fs/ext4/extents.c:4674
 vfs_fallocate+0x463/0x660 fs/open.c:311
 ksys_fallocate fs/open.c:334 [inline]
 __do_sys_fallocate fs/open.c:342 [inline]
 __se_sys_fallocate fs/open.c:340 [inline]
 __x64_sys_fallocate+0x75/0xc0 fs/open.c:340
 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7482 Comm: syz-executor.4 Not tainted 5.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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