From patchwork Wed Mar 22 15:57:15 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 742162 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3vpDpm1xlDz9s3l for ; Thu, 23 Mar 2017 02:57:36 +1100 (AEDT) Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="bxRK6kZL"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760407AbdCVP5e (ORCPT ); Wed, 22 Mar 2017 11:57:34 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:35941 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759469AbdCVP5S (ORCPT ); Wed, 22 Mar 2017 11:57:18 -0400 Received: by mail-pg0-f66.google.com with SMTP id 81so23206530pgh.3 for ; Wed, 22 Mar 2017 08:57:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=xr/1RRUgi5AevvyvmG+WvX7ZQTr7r3QQXGVc+MXtm7o=; b=bxRK6kZLTPgWjP3co8cs8fIGiZL2na/x3El+B6Gf6kyQkM/8iVbQpTbUkVs7Qnl1Gc 86NZAkvtYE8nVlfHH2LuKnM+jzzrUp+lFt97UPZxD0YZgg93oBjY75JDbDm/QCmlnvTh W8ohrvk/tHzxeuKE/M7avgLhGjN7IjXJ5FdyKj6a2vp/3Wmem5g+d8MleWqLW1ECyKVd MoeQXj/xiTOOkJdpOqu6+yHZZOQm+qp2erpr6NlSnL3EZ4cFuswPlGq6t68HbWfNkj33 4BrV29oNI/15v4yJnDn2u0KrNwQbA+nCJCr02IF/NnJma9QuiZsL+e0NrnkG+uRvoZEW LEIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=xr/1RRUgi5AevvyvmG+WvX7ZQTr7r3QQXGVc+MXtm7o=; b=iYjcUPdsNfVa/AG995lwxcZA3+hwq3FRkGpqZRaWjiIdjb1eI5vv7IaOl4QHVqOcbT 0RrblysbL2xj87X5SRj5LsGuqyPiP4Hwu2kANwkwFBFWOr02vQ+M9+LFhv68/o+8PtMy 2qzqnLWgsrDAStINjnG9/4oCqaLP05fZ+1safs4Tpkt3mq2oifdWfFzEmcKs/fooiHaO W5jPA8onNwf+5Csx1Fjo951gO4auOuKvuS4fAPJdfe1GJwmciemD1p7H5HAQvKFnVKaZ bC3WmrLMCN2n/W8DDwMDlPXZrsDd5ODD5mmbVF9OS4HyIRZxK3jg3bj5GGfGQPij7A3Q Y8hA== X-Gm-Message-State: AFeK/H2M6TY+Rp2p5rF/ppx6pDsheTDihe2eDla/V6F7qML+RPxD9237oWT7D+OV/VBsWg== X-Received: by 10.98.110.193 with SMTP id j184mr46004849pfc.228.1490198236784; Wed, 22 Mar 2017 08:57:16 -0700 (PDT) Received: from ?IPv6:2620:0:1000:1704:20dd:f39d:974a:46df? ([2620:0:1000:1704:20dd:f39d:974a:46df]) by smtp.googlemail.com with ESMTPSA id b10sm4873447pga.39.2017.03.22.08.57.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Mar 2017 08:57:16 -0700 (PDT) Message-ID: <1490198235.16816.172.camel@edumazet-glaptop3.roam.corp.google.com> Subject: [PATCH net] inet: frag: release spinlock before calling icmp_send() From: Eric Dumazet To: Dmitry Vyukov Cc: David Miller , Eric Dumazet , netdev Date: Wed, 22 Mar 2017 08:57:15 -0700 In-Reply-To: References: X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet Dmitry reported a lockdep splat [1] (false positive) that we can fix by releasing the spinlock before calling icmp_send() from ip_expire() This is a false positive because sending an ICMP message can not possibly re-enter the IP frag engine. [1] [ INFO: possible circular locking dependency detected ] 4.10.0+ #29 Not tainted ------------------------------------------------------- modprobe/12392 is trying to acquire lock: (_xmit_ETHER#2){+.-...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] (_xmit_ETHER#2){+.-...}, at: [] __netif_tx_lock include/linux/netdevice.h:3486 [inline] (_xmit_ETHER#2){+.-...}, at: [] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 but task is already holding lock: (&(&q->lock)->rlock){+.-...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] (&(&q->lock)->rlock){+.-...}, at: [] ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&(&q->lock)->rlock){+.-...}: validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] ip_defrag+0x3a2/0x4130 net/ipv4/ip_fragment.c:669 ip_check_defrag+0x4e3/0x8b0 net/ipv4/ip_fragment.c:713 packet_rcv_fanout+0x282/0x800 net/packet/af_packet.c:1459 deliver_skb net/core/dev.c:1834 [inline] dev_queue_xmit_nit+0x294/0xa90 net/core/dev.c:1890 xmit_one net/core/dev.c:2903 [inline] dev_hard_start_xmit+0x16b/0xab0 net/core/dev.c:2923 sch_direct_xmit+0x31f/0x6d0 net/sched/sch_generic.c:182 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_resolve_output+0x6b9/0xb10 net/core/neighbour.c:1308 neigh_output include/net/neighbour.h:478 [inline] ip_finish_output2+0x8b8/0x15a0 net/ipv4/ip_output.c:228 ip_do_fragment+0x1d93/0x2720 net/ipv4/ip_output.c:672 ip_fragment.constprop.54+0x145/0x200 net/ipv4/ip_output.c:545 ip_finish_output+0x82d/0xe10 net/ipv4/ip_output.c:314 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 raw_sendmsg+0x26de/0x3a00 net/ipv4/raw.c:655 inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 ___sys_sendmsg+0x4a3/0x9f0 net/socket.c:1985 __sys_sendmmsg+0x25c/0x750 net/socket.c:2075 SYSC_sendmmsg net/socket.c:2106 [inline] SyS_sendmmsg+0x35/0x60 net/socket.c:2101 do_syscall_64+0x2e8/0x930 arch/x86/entry/common.c:281 return_from_SYSCALL_64+0x0/0x7a -> #0 (_xmit_ETHER#2){+.-...}: check_prev_add kernel/locking/lockdep.c:1830 [inline] check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940 validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] __netif_tx_lock include/linux/netdevice.h:3486 [inline] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_hh_output include/net/neighbour.h:468 [inline] neigh_output include/net/neighbour.h:476 [inline] ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268 expire_timers kernel/time/timer.c:1307 [inline] __run_timers+0x960/0xcf0 kernel/time/timer.c:1601 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:657 [inline] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707 __read_once_size include/linux/compiler.h:254 [inline] atomic_read arch/x86/include/asm/atomic.h:26 [inline] rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline] __rcu_is_watching kernel/rcu/tree.c:1133 [inline] rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147 rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline] filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335 do_fault_around mm/memory.c:3231 [inline] do_read_fault mm/memory.c:3265 [inline] do_fault+0xbd5/0x2080 mm/memory.c:3370 handle_pte_fault mm/memory.c:3600 [inline] __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&q->lock)->rlock); lock(_xmit_ETHER#2); lock(&(&q->lock)->rlock); lock(_xmit_ETHER#2); *** DEADLOCK *** 10 locks held by modprobe/12392: #0: (&mm->mmap_sem){++++++}, at: [] __do_page_fault+0x2b8/0xb60 arch/x86/mm/fault.c:1336 #1: (rcu_read_lock){......}, at: [] filemap_map_pages+0x1e6/0x1570 mm/filemap.c:2324 #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] pte_alloc_one_map mm/memory.c:2944 [inline] #2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [] alloc_set_pte+0x13b8/0x1b90 mm/memory.c:3072 #3: (((&q->timer))){+.-...}, at: [] lockdep_copy_map include/linux/lockdep.h:175 [inline] #3: (((&q->timer))){+.-...}, at: [] call_timer_fn+0x1c2/0x820 kernel/time/timer.c:1258 #4: (&(&q->lock)->rlock){+.-...}, at: [] spin_lock include/linux/spinlock.h:299 [inline] #4: (&(&q->lock)->rlock){+.-...}, at: [] ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201 #5: (rcu_read_lock){......}, at: [] ip_expire+0x1b3/0x6c0 net/ipv4/ip_fragment.c:216 #6: (slock-AF_INET){+.-...}, at: [] spin_trylock include/linux/spinlock.h:309 [inline] #6: (slock-AF_INET){+.-...}, at: [] icmp_xmit_lock net/ipv4/icmp.c:219 [inline] #6: (slock-AF_INET){+.-...}, at: [] icmp_send+0x803/0x1c80 net/ipv4/icmp.c:681 #7: (rcu_read_lock_bh){......}, at: [] ip_finish_output2+0x2c1/0x15a0 net/ipv4/ip_output.c:198 #8: (rcu_read_lock_bh){......}, at: [] __dev_queue_xmit+0x23e/0x1e60 net/core/dev.c:3324 #9: (dev->qdisc_running_key ?: &qdisc_running_key){+.....}, at: [] dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 stack backtrace: CPU: 0 PID: 12392 Comm: modprobe Not tainted 4.10.0+ #29 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:52 print_circular_bug+0x307/0x3b0 kernel/locking/lockdep.c:1204 check_prev_add kernel/locking/lockdep.c:1830 [inline] check_prevs_add+0xa8f/0x19f0 kernel/locking/lockdep.c:1940 validate_chain kernel/locking/lockdep.c:2267 [inline] __lock_acquire+0x2149/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x33/0x50 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:299 [inline] __netif_tx_lock include/linux/netdevice.h:3486 [inline] sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180 __dev_xmit_skb net/core/dev.c:3092 [inline] __dev_queue_xmit+0x13e5/0x1e60 net/core/dev.c:3358 dev_queue_xmit+0x17/0x20 net/core/dev.c:3423 neigh_hh_output include/net/neighbour.h:468 [inline] neigh_output include/net/neighbour.h:476 [inline] ip_finish_output2+0xf6c/0x15a0 net/ipv4/ip_output.c:228 ip_finish_output+0xa29/0xe10 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:246 [inline] ip_output+0x1f0/0x7a0 net/ipv4/ip_output.c:404 dst_output include/net/dst.h:486 [inline] ip_local_out+0x95/0x170 net/ipv4/ip_output.c:124 ip_send_skb+0x3c/0xc0 net/ipv4/ip_output.c:1492 ip_push_pending_frames+0x64/0x80 net/ipv4/ip_output.c:1512 icmp_push_reply+0x372/0x4d0 net/ipv4/icmp.c:394 icmp_send+0x156c/0x1c80 net/ipv4/icmp.c:754 ip_expire+0x40e/0x6c0 net/ipv4/ip_fragment.c:239 call_timer_fn+0x241/0x820 kernel/time/timer.c:1268 expire_timers kernel/time/timer.c:1307 [inline] __run_timers+0x960/0xcf0 kernel/time/timer.c:1601 run_timer_softirq+0x21/0x80 kernel/time/timer.c:1614 __do_softirq+0x31f/0xbe7 kernel/softirq.c:284 invoke_softirq kernel/softirq.c:364 [inline] irq_exit+0x1cc/0x200 kernel/softirq.c:405 exiting_irq arch/x86/include/asm/apic.h:657 [inline] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:962 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:707 RIP: 0010:__read_once_size include/linux/compiler.h:254 [inline] RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline] RIP: 0010:rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:350 [inline] RIP: 0010:__rcu_is_watching kernel/rcu/tree.c:1133 [inline] RIP: 0010:rcu_is_watching+0x83/0x110 kernel/rcu/tree.c:1147 RSP: 0000:ffff8801c391f120 EFLAGS: 00000a03 ORIG_RAX: ffffffffffffff10 RAX: dffffc0000000000 RBX: ffff8801c391f148 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 000055edd4374000 RDI: ffff8801dbe1ae0c RBP: ffff8801c391f1a0 R08: 0000000000000002 R09: 0000000000000000 R10: dffffc0000000000 R11: 0000000000000002 R12: 1ffff10038723e25 R13: ffff8801dbe1ae00 R14: ffff8801c391f680 R15: dffffc0000000000 rcu_read_lock_held+0x87/0xc0 kernel/rcu/update.c:293 radix_tree_deref_slot include/linux/radix-tree.h:238 [inline] filemap_map_pages+0x6d4/0x1570 mm/filemap.c:2335 do_fault_around mm/memory.c:3231 [inline] do_read_fault mm/memory.c:3265 [inline] do_fault+0xbd5/0x2080 mm/memory.c:3370 handle_pte_fault mm/memory.c:3600 [inline] __handle_mm_fault+0x1062/0x2cb0 mm/memory.c:3714 handle_mm_fault+0x1e2/0x480 mm/memory.c:3751 __do_page_fault+0x4f6/0xb60 arch/x86/mm/fault.c:1397 do_page_fault+0x54/0x70 arch/x86/mm/fault.c:1460 page_fault+0x28/0x30 arch/x86/entry/entry_64.S:1011 RIP: 0033:0x7f83172f2786 RSP: 002b:00007fffe859ae80 EFLAGS: 00010293 RAX: 000055edd4373040 RBX: 00007f83175111c8 RCX: 000055edd4373238 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f8317510970 RBP: 00007fffe859afd0 R08: 0000000000000009 R09: 0000000000000000 R10: 0000000000000064 R11: 0000000000000000 R12: 000055edd4373040 R13: 0000000000000000 R14: 00007fffe859afe8 R15: 0000000000000000 Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov --- net/ipv4/ip_fragment.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index bbe7f72db9c157ba2d6c5292637c2f58ad39a123..b3cdeec85f1f2c612c362590e828f50596a5c247 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -198,6 +198,7 @@ static void ip_expire(unsigned long arg) qp = container_of((struct inet_frag_queue *) arg, struct ipq, q); net = container_of(qp->q.net, struct net, ipv4.frags); + rcu_read_lock(); spin_lock(&qp->q.lock); if (qp->q.flags & INET_FRAG_COMPLETE) @@ -207,7 +208,7 @@ static void ip_expire(unsigned long arg) __IP_INC_STATS(net, IPSTATS_MIB_REASMFAILS); if (!inet_frag_evicting(&qp->q)) { - struct sk_buff *head = qp->q.fragments; + struct sk_buff *clone, *head = qp->q.fragments; const struct iphdr *iph; int err; @@ -216,32 +217,40 @@ static void ip_expire(unsigned long arg) if (!(qp->q.flags & INET_FRAG_FIRST_IN) || !qp->q.fragments) goto out; - rcu_read_lock(); head->dev = dev_get_by_index_rcu(net, qp->iif); if (!head->dev) - goto out_rcu_unlock; + goto out; + /* skb has no dst, perform route lookup again */ iph = ip_hdr(head); err = ip_route_input_noref(head, iph->daddr, iph->saddr, iph->tos, head->dev); if (err) - goto out_rcu_unlock; + goto out; /* Only an end host needs to send an ICMP * "Fragment Reassembly Timeout" message, per RFC792. */ if (frag_expire_skip_icmp(qp->user) && (skb_rtable(head)->rt_type != RTN_LOCAL)) - goto out_rcu_unlock; + goto out; + + clone = skb_clone(head, GFP_ATOMIC); /* Send an ICMP "Fragment Reassembly Timeout" message. */ - icmp_send(head, ICMP_TIME_EXCEEDED, ICMP_EXC_FRAGTIME, 0); -out_rcu_unlock: - rcu_read_unlock(); + if (clone) { + spin_unlock(&qp->q.lock); + icmp_send(clone, ICMP_TIME_EXCEEDED, + ICMP_EXC_FRAGTIME, 0); + consume_skb(clone); + goto out_rcu_unlock; + } } out: spin_unlock(&qp->q.lock); +out_rcu_unlock: + rcu_read_unlock(); ipq_put(qp); }