==================================================================
BUG: KCSAN: data-race in copy_page_from_iter / copy_page_from_iter

write to 0xffff88807f484000 of 4096 bytes by task 20389 on cpu 0:
 instrument_copy_from_user include/linux/instrumented.h:106 [inline]
 copyin lib/iov_iter.c:151 [inline]
 copy_page_from_iter_iovec lib/iov_iter.c:296 [inline]
 copy_page_from_iter+0x31f/0x5a0 lib/iov_iter.c:942
 process_vm_rw_pages mm/process_vm_access.c:46 [inline]
 process_vm_rw_single_vec mm/process_vm_access.c:120 [inline]
 process_vm_rw_core+0x478/0x760 mm/process_vm_access.c:218
 process_vm_rw+0x14e/0x1d0 mm/process_vm_access.c:286
 __do_sys_process_vm_writev mm/process_vm_access.c:308 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
 __x64_sys_process_vm_writev+0x76/0x90 mm/process_vm_access.c:303
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88807f484000 of 4096 bytes by task 20393 on cpu 1:
 instrument_copy_from_user include/linux/instrumented.h:106 [inline]
 copyin lib/iov_iter.c:151 [inline]
 copy_page_from_iter_iovec lib/iov_iter.c:296 [inline]
 copy_page_from_iter+0x31f/0x5a0 lib/iov_iter.c:942
 process_vm_rw_pages mm/process_vm_access.c:46 [inline]
 process_vm_rw_single_vec mm/process_vm_access.c:120 [inline]
 process_vm_rw_core+0x478/0x760 mm/process_vm_access.c:218
 process_vm_rw+0x14e/0x1d0 mm/process_vm_access.c:286
 __do_sys_process_vm_writev mm/process_vm_access.c:308 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:303 [inline]
 __x64_sys_process_vm_writev+0x76/0x90 mm/process_vm_access.c:303
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 20393 Comm: syz-executor.1 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================