==================================================================
BUG: KCSAN: data-race in copy_process / mm_access

write to 0xffff8881454f50ac of 4 bytes by task 27918 on cpu 0:
 copy_process+0x608/0x2e00 kernel/fork.c:1986
 kernel_clone+0x14b/0x680 kernel/fork.c:2503
 __do_sys_clone kernel/fork.c:2620 [inline]
 __se_sys_clone kernel/fork.c:2604 [inline]
 __x64_sys_clone+0xb4/0xe0 kernel/fork.c:2604
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881454f50ac of 4 bytes by task 27920 on cpu 1:
 get_task_mm kernel/fork.c:1226 [inline]
 mm_access+0x87/0x1a0 kernel/fork.c:1245
 proc_mem_open+0x39/0xf0 fs/proc/base.c:799
 pagemap_open+0x1b/0x50 fs/proc/task_mmu.c:1670
 do_dentry_open+0x53e/0x830 fs/open.c:826
 vfs_open+0x43/0x50 fs/open.c:940
 do_open fs/namei.c:3361 [inline]
 path_openat+0x184e/0x20b0 fs/namei.c:3494
 do_filp_open+0xd9/0x1f0 fs/namei.c:3521
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_openat fs/open.c:1219 [inline]
 __se_sys_openat fs/open.c:1214 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1214
 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27920 Comm: syz-executor.2 Not tainted 5.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================