KCSAN: data-race in __xa_set_mark / ext4

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in __xa_set_mark / ext4_writepages (2) ext4				1	1096d	1094d	0/26	auto-closed as invalid on 2021/05/29 21:52

================================================================== BUG: KCSAN: data-race in __xa_set_mark / ext4_writepages write to 0xffff888113b716b4 of 4 bytes by task 18939 on cpu 1: xa_mark_set lib/xarray.c:69 [inline] xas_set_mark lib/xarray.c:889 [inline] __xa_set_mark+0x2d9/0x2f0 lib/xarray.c:1898 __set_page_dirty+0x17e/0x1d0 fs/buffer.c:609 mark_buffer_dirty+0x126/0x230 fs/buffer.c:1137 __block_commit_write fs/buffer.c:2084 [inline] block_write_end+0x13d/0x230 fs/buffer.c:2162 ext4_write_end+0x185/0x9f0 fs/ext4/inode.c:1283 ext4_da_write_end+0x91/0x750 fs/ext4/inode.c:3060 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3536 ext4_buffered_write_iter+0x2ce/0x3b0 fs/ext4/file.c:269 ext4_file_write_iter+0x480/0x10b0 fs/ext4/file.c:501 call_write_iter include/linux/fs.h:1887 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0x630/0x6b0 fs/read_write.c:586 ksys_write+0xce/0x180 fs/read_write.c:639 __do_sys_write fs/read_write.c:651 [inline] __se_sys_write fs/read_write.c:648 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:648 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff888113b716b4 of 4 bytes by task 725 on cpu 0: xa_marked include/linux/xarray.h:416 [inline] mapping_tagged include/linux/fs.h:488 [inline] ext4_writepages+0x158/0x1e20 fs/ext4/inode.c:2649 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __writeback_single_inode+0x84/0x560 fs/fs-writeback.c:1461 writeback_sb_inodes+0x6a0/0x1020 fs/fs-writeback.c:1721 wb_writeback+0x27d/0x660 fs/fs-writeback.c:1894 wb_do_writeback+0x101/0x5d0 fs/fs-writeback.c:2039 wb_workfn+0xb8/0x410 fs/fs-writeback.c:2080 process_one_work+0x3e1/0x950 kernel/workqueue.c:2272 worker_thread+0x635/0xb90 kernel/workqueue.c:2418 kthread+0x1ff/0x220 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 725 Comm: kworker/u4:3 Not tainted 5.9.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ==================================================================