From mboxrd@z Thu Jan 1 00:00:00 1970 From: dormando Subject: Re: [PATCH] ipv4: fix a race in ip4_datagram_release_cb() Date: Wed, 11 Jun 2014 00:38:19 -0700 (PDT) Message-ID: References: <1402407781.3645.426.camel@edumazet-glaptop2.roam.corp.google.com> <1402448128.3645.437.camel@edumazet-glaptop2.roam.corp.google.com> <1402449173.3645.440.camel@edumazet-glaptop2.roam.corp.google.com> <1402450009.3645.444.camel@edumazet-glaptop2.roam.corp.google.com> <1402466090.3645.456.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Alexey Preobrazhensky , Steffen Klassert , David Miller , paulmck@linux.vnet.ibm.com, netdev@vger.kernel.org, Kostya Serebryany , Dmitry Vyukov , Lars Bull , Eric Dumazet , Bruce Curtis , =?ISO-8859-2?Q?Maciej_=AFenczykowski?= , Alexei Starovoitov To: Eric Dumazet Return-path: Received: from rydia.net ([69.46.88.68]:38237 "EHLO mail.rydia.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751161AbaFKHiU (ORCPT ); Wed, 11 Jun 2014 03:38:20 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 11 Jun 2014, dormando wrote: > On Wed, 11 Jun 2014, dormando wrote: > > > On Tue, 10 Jun 2014, Eric Dumazet wrote: > > > > > On Tue, 2014-06-10 at 21:16 -0700, dormando wrote: > > > > > > > Ran our udpkill util against 3.10.42 with both of your patches applied... > > > > seems like it ran a bit longer than normally would with this test (15-20 > > > > minutes), then died: > > > > > > Well, could you try a recent kernel instead ? > > > > > > I can see some races and fixes are probably worth it. > > > > > > $ git log --oneline v3.10.42..v3.15 net/ipv4/route.c > > > fbdc0ad ipv4: initialise the itag variable in __mkroute_input > > > 0d5edc6 ipv4, route: pass 0 instead of LOOPBACK_IFINDEX to fib_validate_source() > > > aad8872 ipv4: add a sock pointer to dst->output() path. > > > 9114615 ipv4: return valid RTA_IIF on ip route get > > > 3ed66e9 net: replace __this_cpu_inc in route.c with raw_cpu_inc > > > 0b8c7f6 ipv4: remove ip_rt_dump from route.c > > > 4a4eb21 ipv4: remove ipv4_ifdown_dst from route.c > > > 1e8d642 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > > > a625486 ipv4: fix counter in_slow_tot > > > cd0f0b9 ipv4: distinguish EHOSTUNREACH from the ENETUNREACH > > > 2045cea net: remove unnecessary return's > > > f87c10a ipv4: introduce ip_dst_mtu_maybe_forward and protect forwarding path against pmtu spoofing > > > dcdfdf5 ipv4: fix race in concurrent ip_route_input_slow() > > > 482fc60 ipv4: introduce new IP_MTU_DISCOVER mode IP_PMTUDISC_INTERFACE > > > 0baf2b3 ipv4: shrink rt_cache_stat > > > 0a7e226 ipv4: fix ineffective source address selection > > > 734d272 ipv4: raise IP_MAX_MTU to theoretical limit > > > ca4c3fc net: split rt_genid for ipv4 and ipv6 > > > 2ffae99 ipv4: use next hop exceptions also for input routes > > > fe2c633 net: Convert uses of typedef ctl_table to struct ctl_table > > > 6bc19fb Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > > > 5aad1de ipv4: use separate genid for next hop exceptions > > > f016229 ipv4: rate limit updating of next hop exceptions with same pmtu > > > 387aa65 ipv4: properly refresh rtable entries on pmtu/redirect events > > > > > > > > > > Newest I can realistically roll would be 3.14.6, so I just tried > > that... Without your two patches, it still dies from the UDP bug. > > --> Meant to say here that both *with* and *without* your two new patches > it still crashes. > > > Unfortunately 3.14 has a few regressions.. one is some bad CPU usage i'll > > have to track down, and two something about pstore is broken, so I can't > > get the trace from the crash. It's compressing now and has more of the > > kernel log, but it's missing the actual panic part. > > > > $ git log --oneline v3.14..v3.15 net/ipv4/route.c > > fbdc0ad ipv4: initialise the itag variable in __mkroute_input > > 0d5edc6 ipv4, route: pass 0 instead of LOOPBACK_IFINDEX to fib_validate_source() > > aad8872 ipv4: add a sock pointer to dst->output() path. > > 9114615 ipv4: return valid RTA_IIF on ip route get > > 3ed66e9 net: replace __this_cpu_inc in route.c with raw_cpu_inc > > 0b8c7f6 ipv4: remove ip_rt_dump from route.c > > 4a4eb21 ipv4: remove ipv4_ifdown_dst from route.c > > 1e8d642 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net > > 2045cea net: remove unnecessary return's > > > > No more obvious race fixes. I can try 3.15 fully vanilla but I'm having > > doubts? > > > > We have a few patches on top of this, but none of them are active at the > > time of my test. I've tried removing them in the past and it did nothing > > as well. > > > > Sorry :( > > Spamming now! The pstore'd dmesg looked suspiciously like the boot before I booted the crashed kernel.. checked pstore again and the crash is there after a second reboot (wtf.. will test tomorrow). <4>[ 203.161414] general protection fault: 0000 [#1] SMP <4>[ 203.161531] Modules linked in: xt_TEE xt_dscp xt_DSCP macvlan bridge gpio_ich ipmi_watchdog ipmi_devintf x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel microcode sb_edac edac_core igb ixgbe i2c_algo_bit lpc_ich mfd_core ptp pps_core mdio tpm_tis tpm ipmi_si ipmi_msghandler <4>[ 203.162626] CPU: 3 PID: 28456 Comm: udpkill Not tainted 3.14.6 #1 <4>[ 203.162674] Hardware name: Supermicro X9DRi-LN4+/X9DR3-LN4+/X9DRi-LN4+/X9DR3-LN4+, BIOS 3.0 07/05/2013 <4>[ 203.162726] task: ffff885e5f080000 ti: ffff885e5406c000 task.ti: ffff885e5406c000 <4>[ 203.162777] RIP: 0010:[] [] ipv4_dst_destroy+0x45/0x80 <4>[ 203.162867] RSP: 0018:ffff885e5406dbd8 EFLAGS: 00010246 <4>[ 203.162912] RAX: dead000000200200 RBX: ffff885e4ee03440 RCX: dead000000100100 <4>[ 203.162959] RDX: dead000000100100 RSI: 0000000000000200 RDI: ffffffff81ead102 <4>[ 203.163007] RBP: ffff885e5406dbe8 R08: 0000000000000000 R09: ffff885e5406dd38 <4>[ 203.163054] R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000 <4>[ 203.163102] R13: 0000000000000140 R14: ffff885e5406de10 R15: ffffffff8166a9b0 <4>[ 203.163150] FS: 00007f24d1af9700(0000) GS:ffff882fbfc60000(0000) knlGS:0000000000000000 <4>[ 203.163200] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4>[ 203.163246] CR2: 00007f7650df30f8 CR3: 0000005e46fdd000 CR4: 00000000000407e0 <4>[ 203.163307] Stack: <4>[ 203.163360] 0000000000000000 ffff885e4ee03440 ffff885e5406dc08 ffffffff8161c47a <4>[ 203.163574] ffff885e4ee03440 0000000000000000 ffff885e5406dc28 ffffffff8161c786 <4>[ 203.163786] 0000000000000000 ffff885f70f51f80 ffff885e5406dc48 ffffffff815ffa92 <4>[ 203.163999] Call Trace: <4>[ 203.164058] [] dst_destroy+0x2a/0xe0 <4>[ 203.164118] [] dst_release+0x56/0x80 <4>[ 203.164183] [] sk_dst_check+0x82/0x90 <4>[ 203.164247] [] udp_sendmsg+0x585/0x830 <4>[ 203.164314] [] inet_sendmsg+0x45/0xb0 <4>[ 203.164375] [] sock_aio_write+0xc8/0xd0 <4>[ 203.164439] [] do_sync_write+0x5f/0x90 <4>[ 203.164499] [] vfs_write+0x1d1/0x1e0 <4>[ 203.164559] [] SyS_write+0x5a/0xd0 <4>[ 203.164622] [] system_call_fastpath+0x16/0x1b <4>[ 203.164681] Code: 87 b0 00 00 00 74 4f 48 c7 c7 02 d1 ea 81 e8 a3 25 0c 00 48 8b 93 b0 00 00 00 48 8b 83 b8 00 00 00 48 b9 00 01 10 00 00 00 ad de <48> 89 42 08 48 c7 c7 02 d1 ea 81 48 89 10 48 ba 00 02 20 00 00 <1>[ 203.167034] RIP [] ipv4_dst_destroy+0x45/0x80 <4>[ 203.167129] RSP <4>[ 203.167193] ---[ end trace 0201f2e2310d79bd ]--- <0>[ 204.422742] Kernel panic - not syncing: Fatal exception in interrupt <0>[ 204.427379] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff)