KCSAN: data-race in munlock_vma_pages_range / try_to_unmap

KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (2)
Status: auto-closed as invalid on 2020/06/03 05:11
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 547d, last: 547d

similar bugs (6):
Kernel	Title	Count	Last	Reported	Patched	Status
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one	1	632d	632d	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 (6)	2	245d	268d	0/22	auto-closed as invalid on 2021/02/24 23:17
upstream	KCSAN: data-race in munlock_vma_pages_range / try_to_unmap_one (4)	2	371d	387d	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	431d	450d	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	334d	334d	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	128d	143d	0/22	auto-closed as invalid on 2021/06/22 19:33

Sample crash report:

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

write to 0xffff8880a7257b40 of 8 bytes by task 25800 on cpu 0:
 munlock_vma_pages_range+0x57/0x6b0 mm/mlock.c:448
 munlock_vma_pages_all mm/internal.h:306 [inline]
 exit_mmap+0x243/0x2f0 mm/mmap.c:3114
 __mmput kernel/fork.c:1088 [inline]
 mmput+0xe2/0x260 kernel/fork.c:1109
 exit_mm kernel/exit.c:485 [inline]
 do_exit+0x640/0x1880 kernel/exit.c:788
 do_group_exit+0xae/0x1a0 kernel/exit.c:899
 __do_sys_exit_group kernel/exit.c:910 [inline]
 __se_sys_exit_group kernel/exit.c:908 [inline]
 __x64_sys_exit_group+0x2b/0x30 kernel/exit.c:908
 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880a7257b40 of 8 bytes by task 25838 on cpu 1:
 try_to_unmap_one+0x33a/0x1740 mm/rmap.c:1432
 rmap_walk_file+0x240/0x590 mm/rmap.c:1920
 rmap_walk+0x10e/0x180 mm/rmap.c:1938
 try_to_munlock+0x8e/0xb0 mm/rmap.c:1789
 __munlock_isolated_page+0x85/0x190 mm/mlock.c:138
 __munlock_pagevec+0x316/0x690 mm/mlock.c:346
 munlock_vma_pages_range+0x52a/0x6b0 mm/mlock.c:499
 munlock_vma_pages_all mm/internal.h:306 [inline]
 exit_mmap+0x243/0x2f0 mm/mmap.c:3114
 __mmput kernel/fork.c:1088 [inline]
 mmput+0xe2/0x260 kernel/fork.c:1109
 exit_mm kernel/exit.c:485 [inline]
 do_exit+0x640/0x1880 kernel/exit.c:788
 do_group_exit+0xae/0x1a0 kernel/exit.c:899
 get_signal+0x2a7/0x1290 kernel/signal.c:2734
 do_signal+0x2b/0x670 arch/x86/kernel/signal.c:813
 exit_to_usermode_loop+0x24a/0x2c0 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x36e/0x390 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 25838 Comm: syz-executor.3 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci2-upstream-kcsan-gce	2020/03/25 05:06	https://github.com/google/ktsan.git kcsan	40959e34d670	41f049cc	.config	log	report