syzbot


KCSAN: data-race in mlock_new_folio / need_mlock_drain (2)

Status: moderation: reported on 2023/12/10 00:07
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+ce1000eb38d0a51cb3fb@syzkaller.appspotmail.com
First crash: 101d, last: 19d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in mlock_new_folio / need_mlock_drain mm 2 140d 164d 0/26 auto-obsoleted due to no activity on 2023/11/08 14:06

Sample crash report:
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
==================================================================
BUG: KCSAN: data-race in mlock_new_folio / need_mlock_drain

read-write to 0xffff888237d2a210 of 1 bytes by task 10883 on cpu 1:
 folio_batch_add include/linux/pagevec.h:74 [inline]
 mlock_new_folio+0x109/0x1f0 mm/mlock.c:281
 folio_add_lru_vma+0x14d/0x160 mm/swap.c:535
 wp_page_copy mm/memory.c:3206 [inline]
 do_wp_page+0x1551/0x1f20 mm/memory.c:3525
 handle_pte_fault mm/memory.c:5160 [inline]
 __handle_mm_fault mm/memory.c:5285 [inline]
 handle_mm_fault+0xb80/0x27c0 mm/memory.c:5450
 faultin_page mm/gup.c:958 [inline]
 __get_user_pages+0x402/0xe40 mm/gup.c:1241
 populate_vma_page_range mm/gup.c:1679 [inline]
 __mm_populate+0x216/0x330 mm/gup.c:1788
 mm_populate include/linux/mm.h:3391 [inline]
 __do_sys_mlockall mm/mlock.c:778 [inline]
 __se_sys_mlockall+0x28d/0x320 mm/mlock.c:754
 __x64_sys_mlockall+0x1f/0x30 mm/mlock.c:754
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888237d2a210 of 1 bytes by task 29304 on cpu 0:
 folio_batch_count include/linux/pagevec.h:53 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:236
 cpu_needs_drain mm/swap.c:801 [inline]
 __lru_add_drain_all+0x240/0x420 mm/swap.c:889
 lru_add_drain_all+0x10/0x20 mm/swap.c:905
 invalidate_bdev+0x54/0x70 block/bdev.c:89
 ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1361
 generic_shutdown_super+0xdb/0x210 fs/super.c:646
 kill_block_super+0x2a/0x60 fs/super.c:1680
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7319
 deactivate_locked_super+0x7a/0x1c0 fs/super.c:477
 deactivate_super+0x9b/0xb0 fs/super.c:510
 cleanup_mnt+0x272/0x2e0 fs/namespace.c:1267
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1274
 task_work_run+0x135/0x1a0 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:108 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0xbd/0x130 kernel/entry/common.c:212
 do_syscall_64+0xda/0x1d0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0c -> 0x0f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 29304 Comm: syz-executor.3 Not tainted 6.8.0-rc2-syzkaller-00199-g021533194476 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
==================================================================
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop3): unmounting filesystem 00000000-0000-0000-0000-000000000000.

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/03 01:27 upstream 021533194476 60bf9982 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2024/01/11 06:02 upstream de927f6c0b07 04815ef1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2024/01/06 22:08 upstream 95c8a35f1c01 d0304e9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2023/12/09 19:37 upstream f2e8a57ee903 28b24332 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2023/11/30 20:34 upstream 3b47bc037bd4 f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2023/11/27 07:07 upstream d2da77f431ac 5b429f39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
2023/11/12 19:48 upstream b57b17e88bf5 6d6dbf8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in mlock_new_folio / need_mlock_drain
* Struck through repros no longer work on HEAD.