From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f78.google.com (mail-ot1-f78.google.com [209.85.210.78]) (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 7F7D6331214 for ; Mon, 12 Jan 2026 08:35:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768206927; cv=none; b=dMf6yzuUYnxf0+LJld3TqR9WWELhwB7CcHVTE8BhXke+g/IxnpzZWh4GQxLoRcgNYBA/cImEoj+tyEJgXb9QS0xQr6XJqMv02zPU0tXMyrdBK7pjry8okgWQzUrxzNtvmBhcqqf4A9e1bFdCdNQmWSmFmpCskIOj3eey6fMt8Dc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768206927; c=relaxed/simple; bh=WTVtOpumTFGYus15qkA/UfC7BQZWnNNRbPYkbxx03Fc=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=kocQFTiTMOXoyYFai9XMEWX75eAXPXW8z8tm4qGcecgo78iuitBpK5m13lWvlu6holu/UveJnqmX4eCEl6SrjmkVwBOr0H8t6d/YJ3oblcVFIVZIANMCBVoT8qmeyXlq1BpKyvTMW9n82b5AIWNvNTWqxL4jg7/m2fgUJhARUCY= 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=209.85.210.78 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-ot1-f78.google.com with SMTP id 46e09a7af769-7c7599a6f1fso20117619a34.1 for ; Mon, 12 Jan 2026 00:35:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1768206924; x=1768811724; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=hf3hK9th7s0xLdXJi+JD7lyNJWbgkO4+mlWuq40DxgM=; b=BKmBsI3GjOhAaHpjNtpOinND7ZeqAlDGcy7MjtAN9LnbWwk+gwaoo6wzH6g60orNAH gAdpYMr0OIzQAUnJljTKtDaTnalmH+3hiq8FkGpkCOgs05tBNwCOylPwiNxW0BXQmSId QcHCN9GDuVRs/+xVZUz9C82LVjVik09RXWhvNXticwFrvuM7XX0lMuM2XW92FLT9XLM7 DJ+ZqE+zN4d94tmD56wqfGbyJAhmzxQw1U4sAAvys/d/v1nF2hQRUKPEZJqzSsovBJw+ tpdoJj9t62VMVbWr/slPh4pA6T1XFxdLm1MnsZl3otkQ8GWBlpqWsJ+TaBUO9+IG37dv PEdw== X-Forwarded-Encrypted: i=1; AJvYcCXk/+rk95cCfePrctLvNIIrBVj8s8yVlqqr+4ZrzdbzUBRfw61JQPSU7b9QSwlaxBHZCdLVkHK5f/AnYiOn@vger.kernel.org X-Gm-Message-State: AOJu0YxKIhbz6iV3Q9JYvAwCsdbtDSf5tuYUIK19W4XuRkVxhiocA3oW Xn/yEixYa/xOyceN7QUApXnGfq6shbQpVbm1yiINL7kqhfEXJMNFUxi9/SsnVRWMEuH8p56u1S6 pJddSJWeGdxUS8Oy7wOqrj7EfErg7OkUqgl8ogLRhhKbjxc/Hxn6wtPquIMI= X-Google-Smtp-Source: AGHT+IGUBTzCVtkq1XytkujkGpc6qNJJMsapUeXnQMUoes11HO8TAbYTEw0IuI25LJU+AbHgw2+GiOe8jbB0gzetAv7glJC1Kf8A Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:6101:b0:65c:fa23:2cf7 with SMTP id 006d021491bc7-65f54f7e6b0mr6082478eaf.65.1768206924493; Mon, 12 Jan 2026 00:35:24 -0800 (PST) Date: Mon, 12 Jan 2026 00:35:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6964b24c.050a0220.eaf7.008b.GAE@google.com> Subject: [syzbot] [fs?] KMSAN: kernel-infoleak-after-free in anon_pipe_read From: syzbot To: brauner@kernel.org, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 7f98ab9da046 Merge tag 'for-6.19-rc4-tag' of git://git.ker.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1334af92580000 kernel config: https://syzkaller.appspot.com/x/.config?x=b3903bdf68407a14 dashboard link: https://syzkaller.appspot.com/bug?extid=175753aff92b396b1f30 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/c40942ffda39/disk-7f98ab9d.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/63f72388d8d6/vmlinux-7f98ab9d.xz kernel image: https://storage.googleapis.com/syzbot-assets/751895685a54/bzImage-7f98ab9d.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+175753aff92b396b1f30@syzkaller.appspotmail.com ===================================================== BUG: KMSAN: kernel-infoleak-after-free in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak-after-free in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak-after-free in iterate_ubuf include/linux/iov_iter.h:30 [inline] BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance2 include/linux/iov_iter.h:302 [inline] BUG: KMSAN: kernel-infoleak-after-free in iterate_and_advance include/linux/iov_iter.h:330 [inline] BUG: KMSAN: kernel-infoleak-after-free in _copy_to_iter+0xef3/0x33f0 lib/iov_iter.c:197 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:30 [inline] iterate_and_advance2 include/linux/iov_iter.h:302 [inline] iterate_and_advance include/linux/iov_iter.h:330 [inline] _copy_to_iter+0xef3/0x33f0 lib/iov_iter.c:197 copy_page_to_iter+0x482/0x910 lib/iov_iter.c:374 anon_pipe_read+0x769/0x1e80 fs/pipe.c:343 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x8ed/0xf90 fs/read_write.c:572 ksys_read fs/read_write.c:715 [inline] __do_sys_read fs/read_write.c:724 [inline] __se_sys_read fs/read_write.c:722 [inline] __ia32_sys_read+0x1f9/0x4d0 fs/read_write.c:722 ia32_sys_call+0x191f/0x4340 arch/x86/include/generated/asm/syscalls_32.h:4 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x154/0x320 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 stored to memory at: memcpy_to_folio include/linux/highmem.h:518 [inline] zswap_decompress+0x2bd/0x1000 mm/zswap.c:946 zswap_load+0x262/0x570 mm/zswap.c:1627 swap_read_folio+0x662/0x3050 mm/page_io.c:637 swap_cluster_readahead+0x725/0xb20 mm/swap_state.c:652 shmem_swapin_cluster mm/shmem.c:1745 [inline] shmem_swapin_folio+0x1fd9/0x3ee0 mm/shmem.c:2329 shmem_get_folio_gfp+0x92a/0x1fc0 mm/shmem.c:2489 shmem_get_folio mm/shmem.c:2662 [inline] shmem_file_splice_read+0x350/0x11e0 mm/shmem.c:3567 do_splice_read fs/splice.c:982 [inline] splice_file_to_pipe+0x5b4/0x8f0 fs/splice.c:1292 do_splice+0x29d8/0x30d0 fs/splice.c:1376 __do_splice fs/splice.c:1433 [inline] __do_sys_splice fs/splice.c:1636 [inline] __se_sys_splice+0x549/0x8c0 fs/splice.c:1618 __ia32_sys_splice+0x112/0x1a0 fs/splice.c:1618 ia32_sys_call+0x31a6/0x4340 arch/x86/include/generated/asm/syscalls_32.h:314 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x154/0x320 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: free_pages_prepare mm/page_alloc.c:1328 [inline] free_unref_folios+0x26a/0x29a0 mm/page_alloc.c:3000 folios_put_refs+0xaac/0xb10 mm/swap.c:1002 folios_put include/linux/mm.h:1671 [inline] __folio_batch_release+0xe1/0x100 mm/swap.c:1062 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x929/0x20c0 mm/shmem.c:1137 shmem_truncate_range mm/shmem.c:1249 [inline] shmem_evict_inode+0x22c/0xed0 mm/shmem.c:1379 evict+0x6a9/0xca0 fs/inode.c:837 iput_final fs/inode.c:1951 [inline] iput+0xc6f/0x1070 fs/inode.c:2003 do_unlinkat+0x58a/0xd80 fs/namei.c:5443 __do_sys_unlink fs/namei.c:5474 [inline] __se_sys_unlink fs/namei.c:5472 [inline] __ia32_sys_unlink+0x70/0xa0 fs/namei.c:5472 ia32_sys_call+0x1e4a/0x4340 arch/x86/include/generated/asm/syscalls_32.h:11 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0x154/0x320 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 Bytes 0-1023 of 1024 are uninitialized Memory access of size 1024 starts at ffff8880731d2000 Data copied to user address 0000000056912be0 CPU: 1 UID: 0 PID: 5779 Comm: syz-executor Tainted: G W syzkaller #0 PREEMPT(none) Tainted: [W]=WARN 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