================================================================== BUG: KCSAN: data-race in __add_to_page_cache_locked / ext4_writepages write to 0xffff8880bb9178c0 of 8 bytes by task 10833 on cpu 0: __add_to_page_cache_locked+0x2cc/0x710 mm/filemap.c:868 add_to_page_cache_lru+0xa0/0x1b0 mm/filemap.c:919 pagecache_get_page+0x570/0x970 mm/filemap.c:1721 grab_cache_page_write_begin+0x3f/0x70 mm/filemap.c:3353 ext4_da_write_begin+0x358/0xad0 fs/ext4/inode.c:2966 generic_perform_write+0x196/0x390 mm/filemap.c:3403 ext4_buffered_write_iter+0x2cc/0x3b0 fs/ext4/file.c:270 ext4_file_write_iter+0x57b/0x1000 fs/ext4/file.c:498 call_write_iter include/linux/fs.h:1882 [inline] new_sync_write fs/read_write.c:503 [inline] vfs_write+0x665/0x6f0 fs/read_write.c:578 ksys_write+0xce/0x180 fs/read_write.c:631 __do_sys_write fs/read_write.c:643 [inline] __se_sys_write fs/read_write.c:640 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:640 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880bb9178c0 of 8 bytes by task 10838 on cpu 1: ext4_writepages+0x145/0x1ef0 fs/ext4/inode.c:2650 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:422 __filemap_fdatawrite mm/filemap.c:430 [inline] filemap_flush+0x1f/0x30 mm/filemap.c:457 ext4_alloc_da_blocks+0x4c/0x130 fs/ext4/inode.c:3146 ext4_release_file+0x5b/0x1c0 fs/ext4/file.c:142 __fput+0x246/0x4d0 fs/file_table.c:281 ____fput+0x11/0x20 fs/file_table.c:314 task_work_run+0x8e/0x110 kernel/task_work.c:141 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:139 [inline] exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:166 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:241 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 10838 Comm: syz-executor.1 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================