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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_sb_inodes

write to 0xffff8881691df848 of 8 bytes by task 12235 on cpu 1:
 writeback_sb_inodes+0x3cd/0xd10 fs/fs-writeback.c:1867
 wb_writeback+0x28e/0x700 fs/fs-writeback.c:2051
 wb_do_writeback+0x101/0x510 fs/fs-writeback.c:2196
 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2237
 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276
 process_scheduled_works kernel/workqueue.c:2338 [inline]
 worker_thread+0x7ff/0xae0 kernel/workqueue.c:2424
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

read to 0xffff8881691df848 of 8 bytes by task 2108 on cpu 0:
 __mark_inode_dirty+0xda/0x680 fs/fs-writeback.c:2419
 mark_inode_dirty include/linux/fs.h:2403 [inline]
 dquot_alloc_space include/linux/quotaops.h:317 [inline]
 dquot_alloc_block include/linux/quotaops.h:334 [inline]
 ext4_mb_new_blocks+0x116b/0x1f90 fs/ext4/mballoc.c:5477
 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4245
 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638
 ext4_alloc_file_blocks+0x271/0x720 fs/ext4/extents.c:4432
 ext4_zero_range+0x309/0xa40 fs/ext4/extents.c:4544
 ext4_fallocate+0x226/0x4d0 fs/ext4/extents.c:4681
 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_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000020001 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2108 Comm: syz-executor.3 Tainted: G        W         5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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