From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 838D471B50; Mon, 15 Apr 2024 20:18:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713212318; cv=none; b=V84p/uVMWhsCVD0Ngx8csolozaB/XAgs0jx7Itdv1+DWSjp02N14MU58OCgtwf9YE2NRNzDqGqLuXeIXDrr6a1Hpk9DfCKIxCtjom0ukw65ACDFZ7KnKJZIkXL3Pg99LSikOwogoxnt5IYz/oAJRctYRlcjHkOGDbR5XuVVJ6zA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713212318; c=relaxed/simple; bh=S8oJBdMX/629ukkjWH0ejp39M4hmY1Iw0ybCXRKw0tw=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=UfM1xclt9F334mzLdVe0QE4ZyH9wMms+SxE3Ih1ZBHfpvJuNzdsQOZFlQASXTE3av5ZvHPFZfCvI9ZfgIUxmM1nB1cOhlzaduKh2U0GW9WTKRb91/RR7WDEmievCMK+2AZzYLNc92Vl3/I8APcHXSwoBnyWZh5bKsyhpfDaq2A0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=V8hx5W2y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="V8hx5W2y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3CA0C113CC; Mon, 15 Apr 2024 20:18:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1713212318; bh=S8oJBdMX/629ukkjWH0ejp39M4hmY1Iw0ybCXRKw0tw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=V8hx5W2ydEHFUgYGx6cc4XJKYTXEu2PCH6P/ZVTaYhsxhdCjXmkomQQIlhXWazyBp Lr2zvnnLPEeK7VyEx3HIk/Y53iqk9O5QuD/Ogx9kYHUjHVfgbvG8aLkc9opBhjoUEQ M5U0U52D/qtII2CS/iafSry5pB2++6yNaEdnKngs= Date: Mon, 15 Apr 2024 13:18:37 -0700 From: Andrew Morton To: syzbot Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, bpf@vger.kernel.org Subject: Re: [syzbot] [mm?] KMSAN: kernel-infoleak in bpf_probe_write_user Message-Id: <20240415131837.411c6e05eb7b0af077d6424a@linux-foundation.org> In-Reply-To: <000000000000fe696d0615f120bb@google.com> References: <000000000000fe696d0615f120bb@google.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit (cc bpf@) On Fri, 12 Apr 2024 19:27:25 -0700 syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: fec50db7033e Linux 6.9-rc3 > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=16509ba1180000 > kernel config: https://syzkaller.appspot.com/x/.config?x=13e7da432565d94c > dashboard link: https://syzkaller.appspot.com/bug?extid=79102ed905e5b2dc0fc3 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10a4af9d180000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12980f9d180000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/901017b36ccc/disk-fec50db7.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/16bfcf5618d3/vmlinux-fec50db7.xz > kernel image: https://storage.googleapis.com/syzbot-assets/dc9c5a1e7d02/bzImage-fec50db7.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+79102ed905e5b2dc0fc3@syzkaller.appspotmail.com > > ===================================================== > BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] > BUG: KMSAN: kernel-infoleak in __copy_to_user_inatomic include/linux/uaccess.h:125 [inline] > BUG: KMSAN: kernel-infoleak in copy_to_user_nofault+0x129/0x1f0 mm/maccess.c:149 > instrument_copy_to_user include/linux/instrumented.h:114 [inline] > __copy_to_user_inatomic include/linux/uaccess.h:125 [inline] > copy_to_user_nofault+0x129/0x1f0 mm/maccess.c:149 > ____bpf_probe_write_user kernel/trace/bpf_trace.c:349 [inline] > bpf_probe_write_user+0x104/0x180 kernel/trace/bpf_trace.c:327 > ___bpf_prog_run+0x13fe/0xe0f0 kernel/bpf/core.c:1997 > __bpf_prog_run64+0xb5/0xe0 kernel/bpf/core.c:2236 > bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] > __bpf_prog_run include/linux/filter.h:657 [inline] > bpf_prog_run include/linux/filter.h:664 [inline] > __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] > bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420 > __bpf_trace_kfree+0x29/0x40 include/trace/events/kmem.h:94 > trace_kfree include/trace/events/kmem.h:94 [inline] > kfree+0x6a5/0xa30 mm/slub.c:4377 > vfs_writev+0x12bf/0x1450 fs/read_write.c:978 > do_writev+0x251/0x5c0 fs/read_write.c:1018 > __do_sys_writev fs/read_write.c:1091 [inline] > __se_sys_writev fs/read_write.c:1088 [inline] > __x64_sys_writev+0x98/0xe0 fs/read_write.c:1088 > do_syscall_64+0xd5/0x1f0 > entry_SYSCALL_64_after_hwframe+0x72/0x7a > > Local variable stack created at: > __bpf_prog_run64+0x45/0xe0 kernel/bpf/core.c:2236 > bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline] > __bpf_prog_run include/linux/filter.h:657 [inline] > bpf_prog_run include/linux/filter.h:664 [inline] > __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline] > bpf_trace_run2+0x116/0x300 kernel/trace/bpf_trace.c:2420 > > Bytes 0-7 of 8 are uninitialized > Memory access of size 8 starts at ffff888121ec7ae8 > Data copied to user address 00000000ffffffff > > CPU: 1 PID: 4779 Comm: dhcpcd Not tainted 6.9.0-rc3-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 > ===================================================== > > > --- > 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 syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > 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