KCSAN: data-race in expand_downwards / page_add_new_anon

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in expand_downwards / page_add_new_anon_rmap mm				1	1831d	1831d	0/29	auto-closed as invalid on 2020/08/13 06:26
upstream	KCSAN: data-race in expand_downwards / page_add_new_anon_rmap (3) mm				1	1667d	1667d	0/29	auto-closed as invalid on 2021/01/24 10:19

================================================================== BUG: KCSAN: data-race in expand_downwards / page_add_new_anon_rmap write to 0xffff888125f7e898 of 8 bytes by task 10520 on cpu 1: expand_downwards+0x6d0/0x9c0 mm/mmap.c:2507 expand_stack+0x19/0x20 mm/mmap.c:2564 do_user_addr_fault+0x67e/0x770 arch/x86/mm/fault.c:1344 handle_page_fault arch/x86/mm/fault.c:1429 [inline] exc_page_fault+0xb8/0x330 arch/x86/mm/fault.c:1482 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:538 do_strncpy_from_user lib/strncpy_from_user.c:40 [inline] strncpy_from_user+0x103/0x2e0 lib/strncpy_from_user.c:121 getname_flags+0xb8/0x3d0 fs/namei.c:149 getname+0x15/0x20 fs/namei.c:209 do_sys_openat2+0x2f2/0x500 fs/open.c:1162 do_sys_open fs/open.c:1184 [inline] __do_sys_openat fs/open.c:1200 [inline] __se_sys_openat fs/open.c:1195 [inline] __x64_sys_openat+0xef/0x110 fs/open.c:1195 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff888125f7e898 of 8 bytes by task 10506 on cpu 0: linear_page_index include/linux/pagemap.h:494 [inline] __page_set_anon_rmap mm/rmap.c:1059 [inline] page_add_new_anon_rmap+0x442/0x530 mm/rmap.c:1191 do_anonymous_page+0x99f/0xf40 mm/memory.c:3588 handle_pte_fault mm/memory.c:4398 [inline] __handle_mm_fault mm/memory.c:4535 [inline] handle_mm_fault+0x14fd/0x1af0 mm/memory.c:4633 faultin_page mm/gup.c:878 [inline] __get_user_pages+0xa3d/0x1010 mm/gup.c:1090 populate_vma_page_range mm/gup.c:1423 [inline] __mm_populate+0x24d/0x340 mm/gup.c:1471 mm_populate include/linux/mm.h:2566 [inline] vm_mmap_pgoff+0x133/0x170 mm/util.c:511 ksys_mmap_pgoff+0xe1/0x380 mm/mmap.c:1596 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: 10506 Comm: syz-executor.2 Not tainted 5.9.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================