================================================================== BUG: KCSAN: data-race in balance_dirty_pages / percpu_counter_add_batch write to 0xffff888121bae890 of 8 bytes by task 10660 on cpu 0: percpu_counter_add_batch+0xbc/0x140 lib/percpu_counter.c:91 __add_wb_stat include/linux/backing-dev.h:74 [inline] inc_wb_stat include/linux/backing-dev.h:79 [inline] __test_set_page_writeback+0x721/0x7c0 mm/page-writeback.c:2787 set_page_writeback include/linux/page-flags.h:542 [inline] ext4_bio_write_page+0x159/0xb56 fs/ext4/page-io.c:458 mpage_submit_page+0xd5/0x190 fs/ext4/inode.c:2074 mpage_map_and_submit_buffers+0x35d/0x610 fs/ext4/inode.c:2318 mpage_map_and_submit_extent fs/ext4/inode.c:2457 [inline] ext4_writepages+0x1176/0x1d40 fs/ext4/inode.c:2772 do_writepages+0x6b/0x170 mm/page-writeback.c:2344 __writeback_single_inode+0xaa/0x910 fs/fs-writeback.c:1452 writeback_sb_inodes+0x4c8/0xa10 fs/fs-writeback.c:1716 __writeback_inodes_wb+0xe9/0x1b0 fs/fs-writeback.c:1785 wb_writeback+0x557/0x6a0 fs/fs-writeback.c:1894 wb_check_background_flush fs/fs-writeback.c:1962 [inline] wb_do_writeback fs/fs-writeback.c:2050 [inline] wb_workfn+0x66b/0x970 fs/fs-writeback.c:2078 process_one_work+0x424/0x930 kernel/workqueue.c:2264 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2410 kthread+0x1cb/0x1f0 kernel/kthread.c:255 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff888121bae890 of 8 bytes by task 2134 on cpu 1: wb_stat include/linux/backing-dev.h:89 [inline] wb_dirty_limits mm/page-writeback.c:1550 [inline] balance_dirty_pages+0x1022/0x1ab0 mm/page-writeback.c:1677 balance_dirty_pages_ratelimited+0x6f9/0xa20 mm/page-writeback.c:1913 generic_perform_write+0x224/0x320 mm/filemap.c:3323 ext4_buffered_write_iter+0x14e/0x280 fs/ext4/file.c:270 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1901 [inline] new_sync_write+0x303/0x400 fs/read_write.c:483 __vfs_write+0x9e/0xb0 fs/read_write.c:496 vfs_write fs/read_write.c:558 [inline] vfs_write+0x189/0x380 fs/read_write.c:542 ksys_write+0xc5/0x1a0 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x49/0x60 fs/read_write.c:620 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 2134 Comm: syz-executor.2 Not tainted 5.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================