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KCSAN: data-race in munlock_folio / need_mlock_drain (6)

Status: moderation: reported on 2025/01/26 11:05
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+149aa90ba33e9cd332e1@syzkaller.appspotmail.com
First crash: 61d, last: 12d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in munlock_folio / need_mlock_drain mm 1 696d 696d 0/28 auto-obsoleted due to no activity on 2023/06/05 22:24
upstream KCSAN: data-race in munlock_folio / need_mlock_drain (2) mm 1 542d 542d 0/28 auto-obsoleted due to no activity on 2023/11/07 10:03
upstream KCSAN: data-race in munlock_folio / need_mlock_drain (5) mm 16 143d 298d 0/28 auto-obsoleted due to no activity on 2024/12/31 00:27
upstream KCSAN: data-race in munlock_folio / need_mlock_drain (4) mm 1 336d 336d 0/28 auto-obsoleted due to no activity on 2024/05/31 11:19
upstream KCSAN: data-race in munlock_folio / need_mlock_drain (3) mm 2 438d 467d 0/28 auto-obsoleted due to no activity on 2024/02/18 23:01

Sample crash report:
==================================================================
BUG: KCSAN: data-race in munlock_folio / need_mlock_drain

read-write to 0xffff888237d2b4a8 of 1 bytes by task 7106 on cpu 1:
 folio_batch_add include/linux/pagevec.h:77 [inline]
 munlock_folio+0x42/0x130 mm/mlock.c:301
 munlock_vma_folio mm/internal.h:957 [inline]
 __folio_remove_rmap mm/rmap.c:1603 [inline]
 folio_remove_rmap_ptes+0x18f/0x1a0 mm/rmap.c:1620
 zap_present_folio_ptes mm/memory.c:1535 [inline]
 zap_present_ptes mm/memory.c:1596 [inline]
 do_zap_pte_range mm/memory.c:1698 [inline]
 zap_pte_range mm/memory.c:1742 [inline]
 zap_pmd_range mm/memory.c:1834 [inline]
 zap_pud_range mm/memory.c:1863 [inline]
 zap_p4d_range mm/memory.c:1884 [inline]
 unmap_page_range+0x10c5/0x2660 mm/memory.c:1905
 unmap_single_vma+0x142/0x1d0 mm/memory.c:1951
 unmap_vmas+0x18d/0x2b0 mm/memory.c:1995
 exit_mmap+0x1ae/0x6d0 mm/mmap.c:1284
 __mmput+0x28/0x1d0 kernel/fork.c:1356
 mmput+0x4c/0x60 kernel/fork.c:1378
 exit_mm+0xe4/0x190 kernel/exit.c:570
 do_exit+0x559/0x17f0 kernel/exit.c:925
 do_group_exit+0x102/0x150 kernel/exit.c:1087
 get_signal+0xeb9/0x1000 kernel/signal.c:3036
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x62/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d2b4a8 of 1 bytes by task 6385 on cpu 0:
 folio_batch_count include/linux/pagevec.h:56 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:235
 cpu_needs_drain mm/swap.c:779 [inline]
 __lru_add_drain_all+0x22a/0x3f0 mm/swap.c:867
 lru_add_drain_all+0x10/0x20 mm/swap.c:883
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x571/0x810 fs/ext4/super.c:1356
 generic_shutdown_super+0xe5/0x220 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1710
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7368
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x268/0x2e0 fs/namespace.c:1413
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1420
 task_work_run+0x13a/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00 -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6385 Comm: syz-executor Not tainted 6.14.0-rc6-syzkaller-00205-g3571e8b091f4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/03/16 01:50 upstream 3571e8b091f4 e2826670 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in munlock_folio / need_mlock_drain
2025/03/04 20:16 upstream 99fa936e8e4f c3901742 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in munlock_folio / need_mlock_drain
2025/02/16 09:07 upstream ad1b832bf1cf 40a34ec9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in munlock_folio / need_mlock_drain
2025/02/11 05:30 upstream febbc555cf0f 43f51a00 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in munlock_folio / need_mlock_drain
2025/01/26 11:05 upstream aa22f4da2a46 9fbd772e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in munlock_folio / need_mlock_drain
* Struck through repros no longer work on HEAD.