KCSAN: data-race in munlock_vma_pages_range / try_to_unmap

KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (6)
Status: auto-closed as invalid on 2021/02/24 23:17
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 207d, last: 184d

similar bugs (6):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one	1	570d	570d	0/22	auto-closed as invalid on 2020/03/10 21:44
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (4)	2	310d	326d	0/22	auto-closed as invalid on 2020/10/22 10:22
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (3)	2	370d	389d	0/22	auto-closed as invalid on 2020/08/23 10:47
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (5)	1	273d	273d	0/22	auto-closed as invalid on 2020/11/28 11:46
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (7)	3	66d	82d	0/22	auto-closed as invalid on 2021/06/22 19:33
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (2)	1	486d	486d	0/22	auto-closed as invalid on 2020/06/03 05:11

Sample crash report:

==================================================================
BUG: KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one

read-write to 0xffff88811e0a8d98 of 8 bytes by task 16695 on cpu 1:
 munlock_vma_pages_range+0x44/0x760 mm/mlock.c:424
 munlock_vma_pages_all mm/internal.h:347 [inline]
 exit_mmap+0x128/0x400 mm/mmap.c:3204
 __mmput+0xa2/0x220 kernel/fork.c:1083
 mmput+0x38/0x40 kernel/fork.c:1104
 exit_mm+0x32f/0x420 kernel/exit.c:501
 do_exit+0x41f/0x1690 kernel/exit.c:812
 do_group_exit+0x16f/0x170 kernel/exit.c:922
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:933
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:931
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:931
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88811e0a8d98 of 8 bytes by task 16687 on cpu 0:
 try_to_unmap_one+0xb5/0x1670 mm/rmap.c:1395
 rmap_walk_file+0x260/0x4f0 mm/rmap.c:1927
 rmap_walk mm/rmap.c:1945 [inline]
 try_to_munlock+0xe7/0x150 mm/rmap.c:1796
 __munlock_isolated_page mm/mlock.c:121 [inline]
 __munlock_pagevec+0x97d/0xc30 mm/mlock.c:322
 munlock_vma_pages_range+0x581/0x760 mm/mlock.c:475
 munlock_vma_pages_all mm/internal.h:347 [inline]
 exit_mmap+0x128/0x400 mm/mmap.c:3204
 __mmput+0xa2/0x220 kernel/fork.c:1083
 mmput+0x38/0x40 kernel/fork.c:1104
 exit_mm+0x32f/0x420 kernel/exit.c:501
 do_exit+0x41f/0x1690 kernel/exit.c:812
 do_group_exit+0x16f/0x170 kernel/exit.c:922
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:933
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:931
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:931
 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: 16687 Comm: syz-executor.4 Not tainted 5.11.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (2):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2021/01/20 23:11	upstream	75439bc439e0	d4f4eca5	.config	log	report			info	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one
ci2-upstream-kcsan-gce	2020/12/28 23:58	upstream	c76e02c59e13	8259d56c	.config	log	report			info