syzbot


KCSAN: data-race in mlock_folio / need_mlock_drain (5)

Status: moderation: reported on 2024/06/06 10:01
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+214a55f0f497d691a352@syzkaller.appspotmail.com
First crash: 9d07h, last: 9d07h
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in mlock_folio / need_mlock_drain (2) mm 1 302d 302d 0/27 auto-obsoleted due to no activity on 2023/09/21 20:14
upstream KCSAN: data-race in mlock_folio / need_mlock_drain (3) mm 1 172d 172d 0/27 auto-obsoleted due to no activity on 2024/01/30 08:30
upstream KCSAN: data-race in mlock_folio / need_mlock_drain (4) mm 1 53d 53d 0/27 auto-obsoleted due to no activity on 2024/05/28 09:55
upstream KCSAN: data-race in mlock_folio / need_mlock_drain mm 2 340d 340d 0/27 auto-obsoleted due to no activity on 2023/08/15 13:37

Sample crash report:
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
==================================================================
BUG: KCSAN: data-race in mlock_folio / need_mlock_drain

read-write to 0xffff888237c2b410 of 1 bytes by task 4092 on cpu 0:
 folio_batch_add include/linux/pagevec.h:77 [inline]
 mlock_folio+0x136/0x210 mm/mlock.c:257
 mlock_vma_folio mm/internal.h:863 [inline]
 __folio_add_file_rmap mm/rmap.c:1452 [inline]
 folio_add_file_rmap_ptes+0x1a6/0x1b0 mm/rmap.c:1469
 set_pte_range+0x201/0x430 mm/memory.c:4710
 filemap_map_order0_folio mm/filemap.c:3593 [inline]
 filemap_map_pages+0x643/0x9f0 mm/filemap.c:3643
 do_fault_around mm/memory.c:4884 [inline]
 do_read_fault mm/memory.c:4917 [inline]
 do_fault mm/memory.c:5056 [inline]
 do_pte_missing mm/memory.c:3903 [inline]
 handle_pte_fault mm/memory.c:5380 [inline]
 __handle_mm_fault mm/memory.c:5523 [inline]
 handle_mm_fault+0x1092/0x2a80 mm/memory.c:5688
 faultin_page mm/gup.c:1290 [inline]
 __get_user_pages+0x49d/0xf10 mm/gup.c:1589
 populate_vma_page_range mm/gup.c:2029 [inline]
 __mm_populate+0x25b/0x3b0 mm/gup.c:2132
 mm_populate include/linux/mm.h:3464 [inline]
 vm_mmap_pgoff+0x1d6/0x290 mm/util.c:578
 ksys_mmap_pgoff+0x292/0x340 mm/mmap.c:1443
 x64_sys_call+0x1835/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c2b410 of 1 bytes by task 3866 on cpu 1:
 folio_batch_count include/linux/pagevec.h:56 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:235
 cpu_needs_drain mm/swap.c:806 [inline]
 __lru_add_drain_all+0x235/0x410 mm/swap.c:894
 lru_add_drain_all+0x10/0x20 mm/swap.c:910
 invalidate_bdev+0x47/0x70 block/bdev.c:100
 ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1345
 generic_shutdown_super+0xde/0x210 fs/super.c:642
 kill_block_super+0x2a/0x70 fs/super.c:1676
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7301
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x268/0x2e0 fs/namespace.c:1267
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1274
 task_work_run+0x13a/0x1a0 kernel/task_work.c:180
 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:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xbe/0x130 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: 1 PID

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/06 10:00 upstream 2df0193e62cf 121701b6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_folio / need_mlock_drain
* Struck through repros no longer work on HEAD.