From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934099AbbLPM4Z (ORCPT ); Wed, 16 Dec 2015 07:56:25 -0500 Received: from mx2.suse.de ([195.135.220.15]:33859 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754588AbbLPM4W (ORCPT ); Wed, 16 Dec 2015 07:56:22 -0500 Date: Wed, 16 Dec 2015 13:56:18 +0100 From: Jan Kara To: Dmitry Vyukov Cc: Benjamin LaHaise , Alexander Viro , linux-aio , "linux-fsdevel@vger.kernel.org" , LKML , syzkaller , Kostya Serebryany , Alexander Potapenko , Sasha Levin , Andrey Ryabinin Subject: Re: int overflow in io_getevents Message-ID: <20151216125618.GA16918@quack.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 07-12-15 11:27:07, Dmitry Vyukov wrote: > Hello, > > While running syzkaller fuzzer on commit > 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8, I've hit the following UBSAN > warning. I think it can lead to an unexpected active wait loop, if > user-space expects such io_getevents to wait for a long duration but > instead it returns immediately, so user-space reissues the same call > again and again. Andrey suggested that read_events should validate > timeout with timespec_valid_strict before using it. Yup, looks correct. Will you send a patch? Honza > UBSAN: Undefined behaviour in include/linux/ktime.h:55:49 > signed integer overflow: > 1449363382000000000 + 8584381026499825158 cannot be represented in > type 'long long int' > CPU: 0 PID: 27992 Comm: syzkaller_execu Not tainted 4.4.0-rc3+ #150 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > 0000000000000000 ffff880062ab7ae0 ffffffff82c6f2a8 0000000041b58ab3 > ffffffff8788bf8d ffffffff82c6f1f6 ffff880062ab7aa8 ffffffff88479680 > ffff880062ab7be0 7721d90fc5200e06 0000000000000001 ffff880062ab7af0 > Call Trace: > [< inline >] __dump_stack lib/dump_stack.c:15 > [] dump_stack+0xb2/0xfa lib/dump_stack.c:50 > [] ubsan_epilogue+0x12/0x8f lib/ubsan.c:160 > [] handle_overflow+0x22f/0x276 lib/ubsan.c:191 > [] __ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:199 > [< inline >] ktime_set include/linux/ktime.h:55 > [< inline >] timespec_to_ktime include/linux/ktime.h:83 > [] read_events+0x4b7/0x560 fs/aio.c:1273 > [< inline >] SYSC_io_getevents fs/aio.c:1737 > [] SyS_io_getevents+0xc7/0x340 fs/aio.c:1726 > [] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > > Thank you > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jan Kara SUSE Labs, CR