From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f77.google.com (mail-oo1-f77.google.com [209.85.161.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 654DD27472 for ; Mon, 22 Dec 2025 12:18:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766405906; cv=none; b=bB8CnkeKsLoBSpTpQALJ4YuGZiWFeP9fKFfK7Oer6WKPQQaxd9bdWeu5nhzfaMTlWM1iEPc26MPMvvnekVaO6uy8LEMrjDA7tXNY7VE6ncygTdEEV9bJtJD1grV0N5w7qkGoyLDaaQZFFgN4muxL2TfRvGfz086nsNiy5zlm3b4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766405906; c=relaxed/simple; bh=WsYS4JLIhVjnLesXcTq5GCYKqb5Zkl1SzDW9To+tZQk=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=cpAVcL8QWuex30g9gjbbwyDDn4ZpQAHwcCjYPjl1FBbvWWP8sNJp6688GrOmGlEBh7rFS8mhdvTjqNI4Vthv9rHf74A0zFxrNPD+KfVkHy3nA5ArN2GdPpVdtus4SM4ALlHQ5NWMac+h446kcD7I+3fPs69rBmWc0NOKlNBOSDs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.77 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f77.google.com with SMTP id 006d021491bc7-6574475208eso2926954eaf.3 for ; Mon, 22 Dec 2025 04:18:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1766405903; x=1767010703; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=rief4koibS//EOgg16U4TRHGdnZV+IxeLjv0V1PbYuw=; b=cKOn0aypJF4b06raK9wK6DIIlD1kmICpGf9eyKf62KwOQ/d55TivO10QIhGEev2+Mm cfukhMa5C550lpVAcxhIiSvYiCdaBPIPkmcP1Hjgl6nQJ2tZWs7+kWQkk0RHGYskE332 7fO+LJnKRWet10dNqixFPDnJ9gEppRrEm8ytPtTqbjh/HqOlmpYRb6SSPsefcI/SNVLg Sy0iDefm+7TdI3oSyj9q67igRvACDgjvGrGRnj9VhDLSHW/Pi2NAuncONMjC4wht4ZAo P0qUO0+jd4jcRAua5kQT5TKvp2JU5LlvUGxo+bUP2vk4c7A4C1LA/7nIlrJhhhYdQPw4 yobA== X-Forwarded-Encrypted: i=1; AJvYcCX1f1W4nOAg3GCmjEyUN1Mp0pUSHhwAQ79i4ov/YwPZOORK6/LIXEltbTfZ3j9Uhm55arwdfV+LDCnxSdE=@vger.kernel.org X-Gm-Message-State: AOJu0Yz/PD6NYEn71ZkSi+CVbgV/duGRrpufta6vLWTWE0M6svd0xam2 Xd8n1l75ZlKuoTVrHrQOjnn71Az8KNmE/m9uPzwsTkoY3jQm2ywDPb9LOF1D9EFx7RD1tinAcib NbE5Dz275YHtkvInA89VU+u5ioHQvFW14ycJFYCo9aG3gma0lX1/9NrNPOXg= X-Google-Smtp-Source: AGHT+IHJAeBTknAqZdLgB2cQs9bOeo5V1penQ+v8OvcHKVUnjEiNzgymfcCZNchI8xytL8pDQlwn8Mj4B19QINHIdJygSn9lnR9s Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:812:b0:65d:2d2:6d4c with SMTP id 006d021491bc7-65d0e96d58fmr4143164eaf.22.1766405903359; Mon, 22 Dec 2025 04:18:23 -0800 (PST) Date: Mon, 22 Dec 2025 04:18:23 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6949370f.050a0220.1b4e0c.0038.GAE@google.com> Subject: [syzbot] [mm?] KMSAN: uninit-value in swap_writeout From: syzbot To: akpm@linux-foundation.org, baohua@kernel.org, bhe@redhat.com, chrisl@kernel.org, kasong@tencent.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: ea1013c15392 Merge tag 'bpf-fixes' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11d2e31a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b3903bdf68407a14 dashboard link: https://syzkaller.appspot.com/bug?extid=178fff6149127421c2cc compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/27172fba4316/disk-ea1013c1.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/ac8c65aa1d08/vmlinux-ea1013c1.xz kernel image: https://storage.googleapis.com/syzbot-assets/42241f684d1d/bzImage-ea1013c1.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+178fff6149127421c2cc@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: uninit-value in is_folio_zero_filled mm/page_io.c:188 [inline] BUG: KMSAN: uninit-value in swap_writeout+0x468/0x1390 mm/page_io.c:263 is_folio_zero_filled mm/page_io.c:188 [inline] swap_writeout+0x468/0x1390 mm/page_io.c:263 shmem_writeout+0x1abb/0x1f60 mm/shmem.c:1662 writeout mm/vmscan.c:649 [inline] pageout mm/vmscan.c:698 [inline] shrink_folio_list+0x5920/0x7fc0 mm/vmscan.c:1418 evict_folios+0x999d/0xbf30 mm/vmscan.c:4711 try_to_shrink_lruvec+0x12b6/0x17e0 mm/vmscan.c:4874 lru_gen_shrink_lruvec mm/vmscan.c:5023 [inline] shrink_lruvec+0x46f/0x4f10 mm/vmscan.c:5784 shrink_node_memcgs mm/vmscan.c:6020 [inline] shrink_node+0xf1e/0x51e0 mm/vmscan.c:6061 shrink_zones mm/vmscan.c:6300 [inline] do_try_to_free_pages+0x849/0x26b0 mm/vmscan.c:6362 try_to_free_mem_cgroup_pages+0x3ae/0x950 mm/vmscan.c:6690 try_charge_memcg+0x80f/0x1c50 mm/memcontrol.c:2388 obj_cgroup_charge_pages+0x2ed/0x600 mm/memcontrol.c:2823 __memcg_kmem_charge_page+0x14a/0x4c0 mm/memcontrol.c:2867 __alloc_frozen_pages_noprof+0x3ba/0xab0 mm/page_alloc.c:5227 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2486 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline] alloc_pages_noprof+0x102/0x280 mm/mempolicy.c:2577 io_mem_alloc_compound io_uring/memmap.c:30 [inline] io_region_allocate_pages+0x164/0x900 io_uring/memmap.c:165 io_create_region+0x6d0/0x830 io_uring/memmap.c:220 io_allocate_scq_urings+0x1e3/0x8a0 io_uring/io_uring.c:3379 io_uring_create+0x7b5/0x1040 io_uring/io_uring.c:3643 io_uring_setup io_uring/io_uring.c:3718 [inline] __do_sys_io_uring_setup io_uring/io_uring.c:3752 [inline] __se_sys_io_uring_setup+0x3f0/0x410 io_uring/io_uring.c:3743 __ia32_sys_io_uring_setup+0x76/0xb0 io_uring/io_uring.c:3743 ia32_sys_call+0x2c57/0x4340 arch/x86/include/generated/asm/syscalls_32.h:426 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x15a/0x330 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:332 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370 entry_SYSENTER_compat_after_hwframe+0x84/0x8e Uninit was created at: __alloc_frozen_pages_noprof+0x421/0xab0 mm/page_alloc.c:5233 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2486 folio_alloc_mpol_noprof+0x56/0x1d0 mm/mempolicy.c:2505 shmem_alloc_folio mm/shmem.c:1890 [inline] shmem_alloc_and_add_folio+0xc56/0x1bd0 mm/shmem.c:1932 shmem_get_folio_gfp+0xad3/0x1fc0 mm/shmem.c:2556 shmem_get_folio mm/shmem.c:2662 [inline] shmem_symlink+0x562/0xad0 mm/shmem.c:4129 vfs_symlink+0x42f/0x4c0 fs/namei.c:5514 do_symlinkat+0x2ae/0xbb0 fs/namei.c:5541 __do_sys_symlinkat fs/namei.c:5562 [inline] __se_sys_symlinkat fs/namei.c:5559 [inline] __ia32_sys_symlinkat+0xf5/0x180 fs/namei.c:5559 ia32_sys_call+0x385e/0x4340 arch/x86/include/generated/asm/syscalls_32.h:305 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x15a/0x330 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:332 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370 entry_SYSENTER_compat_after_hwframe+0x84/0x8e CPU: 0 UID: 0 PID: 7862 Comm: syz.2.517 Tainted: G L syzkaller #0 PREEMPT(none) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 ===================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup