From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: UBSAN reports issue in ip_idents_reserve Date: Tue, 20 Sep 2016 14:00:00 +0200 Message-ID: <20160920120000.GI1843@nanopsycho.orion> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: netdev@vger.kernel.org, eric.dumazet@gmail.com Return-path: Received: from mail-wm0-f42.google.com ([74.125.82.42]:37339 "EHLO mail-wm0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751563AbcITMAE (ORCPT ); Tue, 20 Sep 2016 08:00:04 -0400 Received: by mail-wm0-f42.google.com with SMTP id b130so31178617wmc.0 for ; Tue, 20 Sep 2016 05:00:03 -0700 (PDT) Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Hi. I'm consistently getting following UBSAN warning on every bootup: [ 47.545820] ================================================================================ [ 47.554340] UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:11 [ 47.561808] signed integer overflow: [ 47.565420] -2117905507 + -695755206 cannot be represented in type 'int' [ 47.572226] CPU: 0 PID: 389 Comm: ntpd Not tainted 4.8.0-rc6jiri+ #1 [ 47.578636] Hardware name: Mellanox Technologies Ltd. Mellanox switch/Mellanox switch, BIOS 4.6.5 05/21/2015 [ 47.588586] ffffffff847bf8c0 00000000987b8f47 ffff8803829af5a8 ffffffff818354e3 [ 47.596165] 0000000041b58ab3 ffffffff8277e711 ffffffff81835431 ffff8803829af5d0 [ 47.603722] ffff8803829af580 ffffffffd6879e3a 1ffffffff08f8214 ffffed0070535e6c [ 47.611298] Call Trace: [ 47.613795] [] dump_stack+0xb2/0x10f [ 47.619077] [] ? _atomic_dec_and_lock+0xa1/0xa1 [ 47.625327] [] ubsan_epilogue+0xd/0x4e [ 47.630811] [] handle_overflow+0x190/0x1de [ 47.636627] [] ? __ubsan_handle_negate_overflow+0x140/0x140 [ 47.643914] [] ? iov_iter_copy_from_user_atomic+0x6e0/0x6e0 [ 47.651219] [] ? __lock_acquire.isra.17+0xb79/0xe50 [ 47.657832] [] ? ip_generic_getfrag+0xd2/0x190 [ 47.664011] [] ? ip_setup_cork+0x320/0x320 [ 47.669827] [] __ubsan_handle_add_overflow+0xe/0x10 [ 47.676444] [] ip_idents_reserve+0xb2/0xe0 [ 47.682254] [] __ip_select_ident+0x159/0x1b0 [ 47.688248] [] ? update_or_create_fnhe+0x850/0x850 [ 47.694782] [] ? ip_setup_cork+0x320/0x320 [ 47.700624] [] __ip_make_skb+0x8a0/0xab0 [ 47.706259] [] ip_make_skb+0x17d/0x1d0 [ 47.711717] [] ? ip_setup_cork+0x320/0x320 [ 47.717526] [] ? ip_flush_pending_frames+0x20/0x20 [ 47.724032] [] ? ip_rt_update_pmtu+0x4f0/0x4f0 [ 47.730231] [] ? xfrm_lookup_route+0x21/0xe0 [ 47.736216] [] udp_sendmsg+0x9db/0xf60 [ 47.741668] [] ? ip_setup_cork+0x320/0x320 [ 47.747472] [] ? udp_abort+0x70/0x70 [ 47.752763] [] inet_sendmsg+0x198/0x220 [ 47.758324] [] ? inet_sendmsg+0x52/0x220 [ 47.763982] [] ? inet_recvmsg+0x300/0x300 [ 47.769728] [] sock_sendmsg+0xa5/0xd0 [ 47.775100] [] SYSC_sendto+0x1d0/0x280 [ 47.780551] [] ? SYSC_connect+0x200/0x200 [ 47.786283] [] ? poll_select_copy_remaining+0x2af/0x310 [ 47.793265] [] ? set_fd_set+0x60/0x60 [ 47.798665] [] ? do_raw_spin_trylock+0x90/0x90 [ 47.804853] [] ? SyS_select+0x1a3/0x200 [ 47.810399] [] ? core_sys_select+0x570/0x570 [ 47.816415] [] ? exit_to_usermode_loop+0xec/0x110 [ 47.822842] [] ? lockdep_sys_exit+0x2d/0xb0 [ 47.828769] [] ? lockdep_sys_exit_thunk+0x16/0x30 [ 47.835199] [] SyS_sendto+0xe/0x10 [ 47.840321] [] entry_SYSCALL_64_fastpath+0x1a/0xa9 [ 47.846826] ================================================================================ Looks like this might be result of following commit: commit 04ca6973f7c1a0d8537f2d9906a0cf8e69886d75 Author: Eric Dumazet Date: Sat Jul 26 08:58:10 2014 +0200 ip: make IP identifiers less predictable Eric, could you please take look at that? Thanks. Jiri