linux-kernel - [syzbot] [mm?] KCSAN: data-race in __unmap_hugepage_range / free_huge

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Message-ID: <67b77c7b.050a0220.14d86d.02f5.GAE@google.com>
Date: Thu, 20 Feb 2025 11:03:23 -0800
From: syzbot <syzbot+4769dec94e62d3835199@...kaller.appspotmail.com>
To: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org, 
	linux-mm@...ck.org, muchun.song@...ux.dev, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] KCSAN: data-race in __unmap_hugepage_range / free_huge_folio

Hello,

syzbot found the following issue on:

HEAD commit:    87a132e73910 Merge tag 'mm-hotfixes-stable-2025-02-19-17-4..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14f42ba4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ce4e433ac2a58cc2
dashboard link: https://syzkaller.appspot.com/bug?extid=4769dec94e62d3835199
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/9b9e85cfddf6/disk-87a132e7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6199597ac06c/vmlinux-87a132e7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/80e28e7cab63/bzImage-87a132e7.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4769dec94e62d3835199@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __unmap_hugepage_range / free_huge_folio

read-write to 0xffffffff88c2b1f8 of 8 bytes by task 8563 on cpu 0:
 remove_hugetlb_folio mm/hugetlb.c:1540 [inline]
 free_huge_folio+0x81a/0xae0 mm/hugetlb.c:1869
 folios_put_refs+0x1ce/0x2b0 mm/swap.c:975
 free_pages_and_swap_cache+0x3c7/0x400 mm/swap_state.c:334
 __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
 tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:389 [inline]
 tlb_flush_mmu+0x2cf/0x440 mm/mmu_gather.c:396
 zap_pte_range mm/memory.c:1781 [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+0x21db/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+0x142/0x150 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1096
 x64_sys_call+0x2db8/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:232
 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 0xffffffff88c2b1f8 of 8 bytes by task 8570 on cpu 1:
 __unmap_hugepage_range+0xbff/0x18c0 mm/hugetlb.c:5644
 unmap_single_vma+0x1c7/0x1d0 mm/memory.c:1947
 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+0x142/0x150 kernel/exit.c:1087
 __do_sys_exit_group kernel/exit.c:1098 [inline]
 __se_sys_exit_group kernel/exit.c:1096 [inline]
 __x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1096
 x64_sys_call+0x2db8/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:232
 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

value changed: 0x0000000000000003 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8570 Comm: syz.4.1159 Not tainted 6.14.0-rc3-syzkaller-00079-g87a132e73910 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================


---
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