linux-kernel - [syzbot] [mm?] KCSAN: data-race in folios_put_refs / need_mlock

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Message-ID: <6728b184.050a0220.35b515.01bc.GAE@google.com>
Date: Mon, 04 Nov 2024 03:35:32 -0800
From: syzbot <syzbot+716d26ee203ef06cc21d@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] KCSAN: data-race in folios_put_refs / need_mlock_drain (2)

Hello,

syzbot found the following issue on:

HEAD commit:    a33ab3f94f51 Merge tag 'kbuild-fixes-v6.12-2' of git://git..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15968740580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bd88d664711c92e2
dashboard link: https://syzkaller.appspot.com/bug?extid=716d26ee203ef06cc21d
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/343e78270f3d/disk-a33ab3f9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/519a20c354c1/vmlinux-a33ab3f9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ad9fc0bdb450/bzImage-a33ab3f9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+716d26ee203ef06cc21d@...kaller.appspotmail.com

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

write to 0xffff888237c2b590 of 1 bytes by task 4698 on cpu 0:
 folio_batch_reinit include/linux/pagevec.h:50 [inline]
 folios_put_refs+0x26d/0x2b0 mm/swap.c:1001
 folios_put include/linux/mm.h:1537 [inline]
 mlock_folio_batch+0x319d/0x31d0 mm/mlock.c:209
 mlock_folio+0x1b7/0x210 mm/mlock.c:259
 mlock_vma_folio mm/internal.h:881 [inline]
 __folio_add_anon_rmap mm/rmap.c:1352 [inline]
 folio_add_anon_rmap_ptes+0x219/0x220 mm/rmap.c:1375
 remove_migration_pte+0x5cb/0x960 mm/migrate.c:332
 rmap_walk_anon+0x28f/0x440 mm/rmap.c:2638
 rmap_walk+0x5b/0x70 mm/rmap.c:2716
 remove_migration_ptes mm/migrate.c:372 [inline]
 migrate_folio_move mm/migrate.c:1387 [inline]
 migrate_pages_batch+0x13a3/0x1950 mm/migrate.c:1897
 migrate_pages_sync mm/migrate.c:1963 [inline]
 migrate_pages+0xff1/0x1820 mm/migrate.c:2072
 do_mbind mm/mempolicy.c:1390 [inline]
 kernel_mbind mm/mempolicy.c:1533 [inline]
 __do_sys_mbind mm/mempolicy.c:1607 [inline]
 __se_sys_mbind+0xf76/0x1160 mm/mempolicy.c:1603
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1603
 x64_sys_call+0x2b4d/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:238
 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 0xffff888237c2b590 of 1 bytes by task 3315 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:792 [inline]
 __lru_add_drain_all+0x22a/0x3f0 mm/swap.c:880
 lru_add_drain_all+0x10/0x20 mm/swap.c:896
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x571/0x840 fs/ext4/super.c:1349
 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:7320
 deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
 deactivate_super+0x9f/0xb0 fs/super.c:506
 cleanup_mnt+0x268/0x2e0 fs/namespace.c:1373
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1380
 task_work_run+0x13a/0x1a0 kernel/task_work.c:239
 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: 0x01 -> 0x00

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3315 Comm: syz-executor Not tainted 6.12.0-rc5-syzkaller-00330-ga33ab3f94f51 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


---
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