==================================================================
BUG: KCSAN: data-race in ext4_alloc_file_blocks / filemap_fault

write to 0xffff88813790f2d0 of 8 bytes by task 19626 on cpu 0:
 i_size_write include/linux/fs.h:871 [inline]
 ext4_update_inode_size fs/ext4/ext4.h:3349 [inline]
 ext4_alloc_file_blocks+0x352/0x720 fs/ext4/extents.c:4446
 ext4_fallocate+0x2a7/0x4d0 fs/ext4/extents.c:4705
 vfs_fallocate+0x463/0x660 fs/open.c:311
 ksys_fallocate fs/open.c:334 [inline]
 __do_sys_fallocate fs/open.c:342 [inline]
 __se_sys_fallocate fs/open.c:340 [inline]
 __x64_sys_fallocate+0x75/0xc0 fs/open.c:340
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88813790f2d0 of 8 bytes by task 19625 on cpu 1:
 i_size_read include/linux/fs.h:849 [inline]
 filemap_fault+0x88/0x7b0 mm/filemap.c:2971
 ext4_filemap_fault+0x4b/0x60 fs/ext4/inode.c:6194
 __do_fault mm/memory.c:3678 [inline]
 do_shared_fault mm/memory.c:4034 [inline]
 do_fault mm/memory.c:4112 [inline]
 handle_pte_fault mm/memory.c:4367 [inline]
 __handle_mm_fault mm/memory.c:4502 [inline]
 handle_mm_fault+0xf76/0x1a70 mm/memory.c:4600
 do_user_addr_fault+0x60c/0xc00 arch/x86/mm/fault.c:1390
 handle_page_fault arch/x86/mm/fault.c:1475 [inline]
 exc_page_fault+0x94/0x230 arch/x86/mm/fault.c:1531
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:577

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 19625 Comm: syz-executor.4 Tainted: G        W         5.13.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================