================================================================== BUG: KCSAN: data-race in __mpage_writepage / truncate_setsize write to 0xffff8880b27311d8 of 8 bytes by task 31493 on cpu 1: i_size_write include/linux/fs.h:876 [inline] truncate_setsize+0x2c/0xc0 mm/truncate.c:839 fat_setattr+0x641/0x760 fs/fat/file.c:536 notify_change+0x7d7/0xa80 fs/attr.c:336 do_truncate+0xe0/0x120 fs/open.c:64 handle_truncate fs/namei.c:2909 [inline] do_open fs/namei.c:3255 [inline] path_openat+0x1a31/0x20a0 fs/namei.c:3368 do_filp_open+0xbd/0x1d0 fs/namei.c:3395 do_sys_openat2+0x33b/0x500 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_sys_creat fs/open.c:1258 [inline] __se_sys_creat fs/open.c:1252 [inline] __x64_sys_creat+0x62/0x80 fs/open.c:1252 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8880b27311d8 of 8 bytes by task 31475 on cpu 0: i_size_read include/linux/fs.h:854 [inline] __mpage_writepage+0x95/0x1070 fs/mpage.c:501 write_cache_pages+0x4cb/0x840 mm/page-writeback.c:2246 mpage_writepages+0x6d/0x120 fs/mpage.c:714 fat_writepages+0x20/0x30 fs/fat/inode.c:205 do_writepages+0x7b/0x150 mm/page-writeback.c:2352 __filemap_fdatawrite_range+0x19b/0x1d0 mm/filemap.c:422 file_write_and_wait_range+0x9f/0x120 mm/filemap.c:761 __generic_file_fsync+0x48/0x140 fs/libfs.c:1072 fat_file_fsync+0x48/0x100 fs/fat/file.c:190 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2744 [inline] generic_file_write_iter+0x3af/0x3e0 mm/filemap.c:3568 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 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 31475 Comm: syz-executor.5 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================