================================================================== BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages write to 0xffff88813244f8f0 of 8 bytes by task 30526 on cpu 1: __add_to_page_cache_locked+0x256/0x4e0 mm/filemap.c:914 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:967 pagecache_get_page+0x6a3/0x900 mm/filemap.c:1896 grab_cache_page_write_begin+0x3f/0x70 mm/filemap.c:3610 ext4_da_write_begin+0x305/0x820 fs/ext4/inode.c:2984 generic_perform_write+0x196/0x3a0 mm/filemap.c:3660 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x69d/0x770 fs/read_write.c:605 ksys_write+0xce/0x180 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:667 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88813244f8f0 of 8 bytes by task 8439 on cpu 0: ext4_writepages+0x111/0x1d10 fs/ext4/inode.c:2668 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 __writeback_inodes_wb fs/fs-writeback.c:1801 [inline] wb_writeback+0x327/0x700 fs/fs-writeback.c:1907 wb_check_start_all fs/fs-writeback.c:2031 [inline] wb_do_writeback+0x330/0x510 fs/fs-writeback.c:2057 wb_workfn+0xc8/0x520 fs/fs-writeback.c:2091 process_one_work+0x3e9/0x8f0 kernel/workqueue.c:2276 worker_thread+0x636/0xae0 kernel/workqueue.c:2422 kthread+0x1d0/0x1f0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 value changed: 0x0000000000000225 -> 0x0000000000000226 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 8439 Comm: kworker/u4:9 Tainted: G W 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: writeback wb_workfn (flush-8:0) ================================================================== sd 0:0:1:0: [sda] Synchronizing SCSI cache