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 ext4				1	1285d	1285d	0/26	auto-closed as invalid on 2020/11/22 17:44

================================================================== BUG: KCSAN: data-race in __xa_set_mark / ext4_writepages write to 0xffff88813081f3f4 of 4 bytes by task 2243 on cpu 1: xa_mark_set lib/xarray.c:69 [inline] xas_set_mark lib/xarray.c:889 [inline] __xa_set_mark+0x279/0x290 lib/xarray.c:1899 __set_page_dirty+0x155/0x1a0 fs/buffer.c:609 mark_buffer_dirty+0x126/0x200 fs/buffer.c:1137 __block_commit_write fs/buffer.c:2084 [inline] block_write_end+0x13d/0x260 fs/buffer.c:2163 ext4_write_end+0x192/0x820 fs/ext4/inode.c:1301 ext4_da_write_end+0x93/0x730 fs/ext4/inode.c:3081 generic_perform_write+0x23e/0x3a0 mm/filemap.c:3593 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:502 call_write_iter include/linux/fs.h:1977 [inline] aio_write+0x287/0x360 fs/aio.c:1581 __io_submit_one fs/aio.c:1840 [inline] io_submit_one+0x82f/0x1350 fs/aio.c:1883 __do_sys_io_submit fs/aio.c:1942 [inline] __se_sys_io_submit+0xf5/0x260 fs/aio.c:1912 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1912 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813081f3f4 of 4 bytes by task 15250 on cpu 0: xa_marked include/linux/xarray.h:418 [inline] mapping_tagged include/linux/fs.h:490 [inline] ext4_writepages+0x130/0x1d10 fs/ext4/inode.c:2670 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __writeback_single_inode+0x80/0x450 fs/fs-writeback.c:1467 writeback_sb_inodes+0x564/0xf10 fs/fs-writeback.c:1732 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 process_scheduled_works kernel/workqueue.c:2337 [inline] worker_thread+0x7ff/0xae0 kernel/workqueue.c:2423 kthread+0x1d0/0x1f0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 15250 Comm: kworker/u4:7 Not tainted 5.12.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ================================================================== EXT4-fs (sda1): Delayed block allocation failed for inode 16381 at logical offset 511 with max blocks 2 with error 28 EXT4-fs (sda1): This should not happen!! Data will be lost EXT4-fs: 30 callbacks suppressed EXT4-fs (sda1): Delayed block allocation failed for inode 15221 at logical offset 7 with max blocks 1 with error 28 EXT4-fs (sda1): This should not happen!! Data will be lost EXT4-fs (sda1): Total free blocks count 0 EXT4-fs (sda1): Free/Dirty block details EXT4-fs (sda1): free_blocks=11040 EXT4-fs (sda1): dirty_blocks=5526 EXT4-fs (sda1): Block reservation details EXT4-fs (sda1): i_reserved_data_blocks=1 EXT4-fs (sda1): Delayed block allocation failed for inode 15350 at logical offset 64 with max blocks 127 with error 28 EXT4-fs (sda1): This should not happen!! Data will be lost