| Age | Commit message (Collapse) | Author | Files | Lines |
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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: [<ffffffff837a8182>] spin_lock
include/linux/spinlock.h:299 [inline]
(_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>] __netif_tx_lock
include/linux/netdevice.h:3486 [inline]
(_xmit_ETHER#2){+.-...}, at: [<ffffffff837a8182>]
sch_direct_xmit+0x282/0x6d0 net/sched/sch_generic.c:180
but task is already holding lock:
(&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
(&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
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: [<ffffffff81329758>]
__do_page_fault+0x2b8/0xb60 arch/x86/mm/fault.c:1336
#1: (rcu_read_lock){......}, at: [<ffffffff8188cab6>]
filemap_map_pages+0x1e6/0x1570 mm/filemap.c:2324
#2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
spin_lock include/linux/spinlock.h:299 [inline]
#2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
pte_alloc_one_map mm/memory.c:2944 [inline]
#2: (&(ptlock_ptr(page))->rlock#2){+.+...}, at: [<ffffffff81984a78>]
alloc_set_pte+0x13b8/0x1b90 mm/memory.c:3072
#3: (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
lockdep_copy_map include/linux/lockdep.h:175 [inline]
#3: (((&q->timer))){+.-...}, at: [<ffffffff81627e72>]
call_timer_fn+0x1c2/0x820 kernel/time/timer.c:1258
#4: (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>] spin_lock
include/linux/spinlock.h:299 [inline]
#4: (&(&q->lock)->rlock){+.-...}, at: [<ffffffff8389a4d1>]
ip_expire+0x51/0x6c0 net/ipv4/ip_fragment.c:201
#5: (rcu_read_lock){......}, at: [<ffffffff8389a633>]
ip_expire+0x1b3/0x6c0 net/ipv4/ip_fragment.c:216
#6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] spin_trylock
include/linux/spinlock.h:309 [inline]
#6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>] icmp_xmit_lock
net/ipv4/icmp.c:219 [inline]
#6: (slock-AF_INET){+.-...}, at: [<ffffffff839b3313>]
icmp_send+0x803/0x1c80 net/ipv4/icmp.c:681
#7: (rcu_read_lock_bh){......}, at: [<ffffffff838ab9a1>]
ip_finish_output2+0x2c1/0x15a0 net/ipv4/ip_output.c:198
#8: (rcu_read_lock_bh){......}, at: [<ffffffff836d1dee>]
__dev_queue_xmit+0x23e/0x1e60 net/core/dev.c:3324
#9: (dev->qdisc_running_key ?: &qdisc_running_key){+.....}, at:
[<ffffffff836d3a27>] 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:
<IRQ>
__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
</IRQ>
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 <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Rename IP_INC_STATS_BH() to __IP_INC_STATS(), to
better express this is used in non preemptible context.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Now that all the ip fragmentation related sysctls are namespaceified
there is no reason to hide them anymore from "root" users inside
containers.
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Later parts of the stack (including fragmentation) expect that there is
never a socket attached to frag in a frag_list, however this invariant
was not enforced on all defrag paths. This could lead to the
BUG_ON(skb->sk) during ip_do_fragment(), as per the call stack at the
end of this commit message.
While the call could be added to openvswitch to fix this particular
error, the head and tail of the frags list are already orphaned
indirectly inside ip_defrag(), so it seems like the remaining fragments
should all be orphaned in all circumstances.
kernel BUG at net/ipv4/ip_output.c:586!
[...]
Call Trace:
<IRQ>
[<ffffffffa0205270>] ? do_output.isra.29+0x1b0/0x1b0 [openvswitch]
[<ffffffffa02167a7>] ovs_fragment+0xcc/0x214 [openvswitch]
[<ffffffff81667830>] ? dst_discard_out+0x20/0x20
[<ffffffff81667810>] ? dst_ifdown+0x80/0x80
[<ffffffffa0212072>] ? find_bucket.isra.2+0x62/0x70 [openvswitch]
[<ffffffff810e0ba5>] ? mod_timer_pending+0x65/0x210
[<ffffffff810b732b>] ? __lock_acquire+0x3db/0x1b90
[<ffffffffa03205a2>] ? nf_conntrack_in+0x252/0x500 [nf_conntrack]
[<ffffffff810b63c4>] ? __lock_is_held+0x54/0x70
[<ffffffffa02051a3>] do_output.isra.29+0xe3/0x1b0 [openvswitch]
[<ffffffffa0206411>] do_execute_actions+0xe11/0x11f0 [openvswitch]
[<ffffffff810b63c4>] ? __lock_is_held+0x54/0x70
[<ffffffffa0206822>] ovs_execute_actions+0x32/0xd0 [openvswitch]
[<ffffffffa020b505>] ovs_dp_process_packet+0x85/0x140 [openvswitch]
[<ffffffff810b63c4>] ? __lock_is_held+0x54/0x70
[<ffffffffa02068a2>] ovs_execute_actions+0xb2/0xd0 [openvswitch]
[<ffffffffa020b505>] ovs_dp_process_packet+0x85/0x140 [openvswitch]
[<ffffffffa0215019>] ? ovs_ct_get_labels+0x49/0x80 [openvswitch]
[<ffffffffa0213a1d>] ovs_vport_receive+0x5d/0xa0 [openvswitch]
[<ffffffff810b732b>] ? __lock_acquire+0x3db/0x1b90
[<ffffffff810b732b>] ? __lock_acquire+0x3db/0x1b90
[<ffffffff810b732b>] ? __lock_acquire+0x3db/0x1b90
[<ffffffffa0214895>] ? internal_dev_xmit+0x5/0x140 [openvswitch]
[<ffffffffa02148fc>] internal_dev_xmit+0x6c/0x140 [openvswitch]
[<ffffffffa0214895>] ? internal_dev_xmit+0x5/0x140 [openvswitch]
[<ffffffff81660299>] dev_hard_start_xmit+0x2b9/0x5e0
[<ffffffff8165fc21>] ? netif_skb_features+0xd1/0x1f0
[<ffffffff81660f20>] __dev_queue_xmit+0x800/0x930
[<ffffffff81660770>] ? __dev_queue_xmit+0x50/0x930
[<ffffffff810b53f1>] ? mark_held_locks+0x71/0x90
[<ffffffff81669876>] ? neigh_resolve_output+0x106/0x220
[<ffffffff81661060>] dev_queue_xmit+0x10/0x20
[<ffffffff816698e8>] neigh_resolve_output+0x178/0x220
[<ffffffff816a8e6f>] ? ip_finish_output2+0x1ff/0x590
[<ffffffff816a8e6f>] ip_finish_output2+0x1ff/0x590
[<ffffffff816a8cee>] ? ip_finish_output2+0x7e/0x590
[<ffffffff816a9a31>] ip_do_fragment+0x831/0x8a0
[<ffffffff816a8c70>] ? ip_copy_metadata+0x1b0/0x1b0
[<ffffffff816a9ae3>] ip_fragment.constprop.49+0x43/0x80
[<ffffffff816a9c9c>] ip_finish_output+0x17c/0x340
[<ffffffff8169a6f4>] ? nf_hook_slow+0xe4/0x190
[<ffffffff816ab4c0>] ip_output+0x70/0x110
[<ffffffff816a9b20>] ? ip_fragment.constprop.49+0x80/0x80
[<ffffffff816aa9f9>] ip_local_out+0x39/0x70
[<ffffffff816abf89>] ip_send_skb+0x19/0x40
[<ffffffff816abfe3>] ip_push_pending_frames+0x33/0x40
[<ffffffff816df21a>] icmp_push_reply+0xea/0x120
[<ffffffff816df93d>] icmp_reply.constprop.23+0x1ed/0x230
[<ffffffff816df9ce>] icmp_echo.part.21+0x4e/0x50
[<ffffffff810b63c4>] ? __lock_is_held+0x54/0x70
[<ffffffff810d5f9e>] ? rcu_read_lock_held+0x5e/0x70
[<ffffffff816dfa06>] icmp_echo+0x36/0x70
[<ffffffff816e0d11>] icmp_rcv+0x271/0x450
[<ffffffff816a4ca7>] ip_local_deliver_finish+0x127/0x3a0
[<ffffffff816a4bc1>] ? ip_local_deliver_finish+0x41/0x3a0
[<ffffffff816a5160>] ip_local_deliver+0x60/0xd0
[<ffffffff816a4b80>] ? ip_rcv_finish+0x560/0x560
[<ffffffff816a46fd>] ip_rcv_finish+0xdd/0x560
[<ffffffff816a5453>] ip_rcv+0x283/0x3e0
[<ffffffff810b6302>] ? match_held_lock+0x192/0x200
[<ffffffff816a4620>] ? inet_del_offload+0x40/0x40
[<ffffffff8165d062>] __netif_receive_skb_core+0x392/0xae0
[<ffffffff8165e68e>] ? process_backlog+0x8e/0x230
[<ffffffff810b53f1>] ? mark_held_locks+0x71/0x90
[<ffffffff8165d7c8>] __netif_receive_skb+0x18/0x60
[<ffffffff8165e678>] process_backlog+0x78/0x230
[<ffffffff8165e6dd>] ? process_backlog+0xdd/0x230
[<ffffffff8165e355>] net_rx_action+0x155/0x400
[<ffffffff8106b48c>] __do_softirq+0xcc/0x420
[<ffffffff816a8e87>] ? ip_finish_output2+0x217/0x590
[<ffffffff8178e78c>] do_softirq_own_stack+0x1c/0x30
<EOI>
[<ffffffff8106b88e>] do_softirq+0x4e/0x60
[<ffffffff8106b948>] __local_bh_enable_ip+0xa8/0xb0
[<ffffffff816a8eb0>] ip_finish_output2+0x240/0x590
[<ffffffff816a9a31>] ? ip_do_fragment+0x831/0x8a0
[<ffffffff816a9a31>] ip_do_fragment+0x831/0x8a0
[<ffffffff816a8c70>] ? ip_copy_metadata+0x1b0/0x1b0
[<ffffffff816a9ae3>] ip_fragment.constprop.49+0x43/0x80
[<ffffffff816a9c9c>] ip_finish_output+0x17c/0x340
[<ffffffff8169a6f4>] ? nf_hook_slow+0xe4/0x190
[<ffffffff816ab4c0>] ip_output+0x70/0x110
[<ffffffff816a9b20>] ? ip_fragment.constprop.49+0x80/0x80
[<ffffffff816aa9f9>] ip_local_out+0x39/0x70
[<ffffffff816abf89>] ip_send_skb+0x19/0x40
[<ffffffff816abfe3>] ip_push_pending_frames+0x33/0x40
[<ffffffff816d55d3>] raw_sendmsg+0x7d3/0xc30
[<ffffffff810b732b>] ? __lock_acquire+0x3db/0x1b90
[<ffffffff816e7557>] ? inet_sendmsg+0xc7/0x1d0
[<ffffffff810b63c4>] ? __lock_is_held+0x54/0x70
[<ffffffff816e759a>] inet_sendmsg+0x10a/0x1d0
[<ffffffff816e7495>] ? inet_sendmsg+0x5/0x1d0
[<ffffffff8163e398>] sock_sendmsg+0x38/0x50
[<ffffffff8163ec5f>] ___sys_sendmsg+0x25f/0x270
[<ffffffff811aadad>] ? handle_mm_fault+0x8dd/0x1320
[<ffffffff8178c147>] ? _raw_spin_unlock+0x27/0x40
[<ffffffff810529b2>] ? __do_page_fault+0x1e2/0x460
[<ffffffff81204886>] ? __fget_light+0x66/0x90
[<ffffffff8163f8e2>] __sys_sendmsg+0x42/0x80
[<ffffffff8163f932>] SyS_sendmsg+0x12/0x20
[<ffffffff8178cb17>] entry_SYSCALL_64_fastpath+0x12/0x6f
Code: 00 00 44 89 e0 e9 7c fb ff ff 4c 89 ff e8 e7 e7 ff ff 41 8b 9d 80 00 00 00 2b 5d d4 89 d8 c1 f8 03 0f b7 c0 e9 33 ff ff f
66 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48
RIP [<ffffffff816a9a92>] ip_do_fragment+0x892/0x8a0
RSP <ffff88006d603170>
Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Signed-off-by: Joe Stringer <joe@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The only user was removed in commit
029f7f3b8701cc7a ("netfilter: ipv6: nf_defrag: avoid/free clone operations").
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This patch fixes following problems :
1) percpu_counter_init() can return an error, therefore
init_frag_mem_limit() must propagate this error so that
inet_frags_init_net() can do the same up to its callers.
2) If ip[46]_frags_ns_ctl_register() fail, we must unwind
properly and free the percpu_counter.
Without this fix, we leave freed object in percpu_counters
global list (if CONFIG_HOTPLUG_CPU) leading to crashes.
This bug was detected by KASAN and syzkaller tool
(http://github.com/google/syzkaller)
Fixes: 6d7b857d541e ("net: use lib/percpu_counter API for fragmentation mem accounting")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The function ip_defrag is called on both the input and the output
paths of the networking stack. In particular conntrack when it is
tracking outbound packets from the local machine calls ip_defrag.
So add a struct net parameter and stop making ip_defrag guess which
network namespace it needs to defragment packets in.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Replace calls to vrf_master_ifindex_rcu and vrf_master_ifindex with either
l3mdev_master_ifindex_rcu or l3mdev_master_ifindex.
The pattern:
oif = vrf_master_ifindex(dev) ? : dev->ifindex;
is replaced with
oif = l3mdev_fib_oif(dev);
And remove the now unused vrf macros.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
inetpeer caches based on address only, so duplicate IP addresses within
a namespace return the same cached entry. Enhance the ipv4 address key
to contain both the IPv4 address and VRF device index.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Fragmentation cache uses information from the IP header to reassemble
packets. That information can be duplicated across VRFs -- same source
and destination addresses, protocol and id. Handle fragmentation with
VRFs by adding the VRF device index to entries in the cache and the
lookup arg.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Conflicts:
arch/s390/net/bpf_jit_comp.c
drivers/net/ethernet/ti/netcp_ethss.c
net/bridge/br_multicast.c
net/ipv4/ip_fragment.c
All four conflicts were cases of simple overlapping
changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
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We can simply remove the INET_FRAG_EVICTED flag to avoid all the flags
race conditions with the evictor and use a participation test for the
evictor list, when we're at that point (after inet_frag_kill) in the
timer there're 2 possible cases:
1. The evictor added the entry to its evictor list while the timer was
waiting for the chainlock
or
2. The timer unchained the entry and the evictor won't see it
In both cases we should be able to see list_evictor correctly due
to the sync on the chainlock.
Joint work with Florian Westphal.
Tested-by: Frank Schreuder <fschreuder@transip.nl>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Followup patch will call it after inet_frag_queue was freed, so q->net
doesn't work anymore (but netf = q->net; free(q); mem_limit(netf) would).
Tested-by: Frank Schreuder <fschreuder@transip.nl>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Conflicts:
net/bridge/br_mdb.c
br_mdb.c conflict was a function call being removed to fix a bug in
'net' but whose signature was changed in 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
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When ip_frag_queue() computes positions, it assumes that the passed
sk_buff does not contain L2 headers.
However, when PACKET_FANOUT_FLAG_DEFRAG is used, IP reassembly
functions can be called on outgoing packets that contain L2 headers.
Also, IPv4 checksum is not corrected after reassembly.
Fixes: 7736d33f4262 ("packet: Add pre-defragmentation support for ipv4 fanouts.")
Signed-off-by: Edward Hyunkoo Jee <edjee@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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This reverts commit 3cc4949269e01f39443d0fcfffb5bc6b47878d45.
There is nothing wrong with coalescing during defragmentation, it
reduces truesize overhead and simplifies things for the receiving
socket (no fraglist walk needed).
However, it also destroys geometry of the original fragments.
While that doesn't cause any breakage (we make sure to not exceed largest
original size) ip_do_fragment contains a 'fastpath' that takes advantage
of a present frag list and results in fragments that (in most cases)
match what was received.
In case its needed the coalescing could be done later, when we're sure
the skb is not forwarded. But discussion during NFWS resulted in
'lets just remove this for now'.
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We currently always send fragments without DF bit set.
Thus, given following setup:
mtu1500 - mtu1500:1400 - mtu1400:1280 - mtu1280
A R1 R2 B
Where R1 and R2 run linux with netfilter defragmentation/conntrack
enabled, then if Host A sent a fragmented packet _with_ DF set to B, R1
will respond with icmp too big error if one of these fragments exceeded
1400 bytes.
However, if R1 receives fragment sizes 1200 and 100, it would
forward the reassembled packet without refragmenting, i.e.
R2 will send an icmp error in response to a packet that was never sent,
citing mtu that the original sender never exceeded.
The other minor issue is that a refragmentation on R1 will conceal the
MTU of R2-B since refragmentation does not set DF bit on the fragments.
This modifies ip_fragment so that we track largest fragment size seen
both for DF and non-DF packets, and set frag_max_size to the largest
value.
If the DF fragment size is larger or equal to the non-df one, we will
consider the packet a path mtu probe:
We set DF bit on the reassembled skb and also tag it with a new IPCB flag
to force refragmentation even if skb fits outdev mtu.
We will also set DF bit on each fragment in this case.
Joint work with Hannes Frederic Sowa.
Reported-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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users in [IP_DEFRAG_CONNTRACK_BRIDGE_IN, __IP_DEFRAG_CONNTRACK_BR_IN]
should not ICMP message also.
Reported-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Improve readability of skip ICMP for de-fragmentation expiration logic.
This change will also make the logic easier to maintain when the
following patches in this series are applied.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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The ipv4 code uses a mixture of coding styles. In some instances check
for NULL pointer is done as x == NULL and sometimes as !x. !x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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ip_check_defrag() may be used by af_packet to defragment outgoing packets.
skb_network_offset() of af_packet's outgoing packets is not zero.
Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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skb_copy_bits() returns zero on success and negative value on error,
so it is needed to invert the condition in ip_check_defrag().
Fixes: 1bf3751ec90c ("ipv4: ip_check_defrag must not modify skb before unsharing")
Signed-off-by: Alexander Drozdov <al.drozdov@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Use the more common dynamic_debug capable net_dbg_ratelimited
and remove the LIMIT_NETDEBUG macro.
All messages are still ratelimited.
Some KERN_<LEVEL> uses are changed to KERN_DEBUG.
This may have some negative impact on messages that were
emitted at KERN_INFO that are not not enabled at all unless
DEBUG is defined or dynamic_debug is enabled. Even so,
these messages are now _not_ emitted by default.
This also eliminates the use of the net_msg_warn sysctl
"/proc/sys/net/core/warnings". For backward compatibility,
the sysctl is not removed, but it has no function. The extern
declaration of net_msg_warn is removed from sock.h and made
static in net/core/sysctl_net_core.c
Miscellanea:
o Update the sysctl documentation
o Remove the embedded uses of pr_fmt
o Coalesce format fragments
o Realign arguments
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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remove __inline__ / inline and let compiler decide what to do
with static functions
Inspired-by: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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ip4_frags_ctl_register is only called by __init ipfrag_init
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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Use kmem_cache to allocate/free inet_frag_queue objects since they're
all the same size per inet_frags user and are alloced/freed in high volumes
thus making it a perfect case for kmem_cache.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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Now that we have INET_FRAG_EVICTED we might as well use it to stop
sending icmp messages in the "frag_expire" functions instead of
stripping INET_FRAG_FIRST_IN from their flags when evicting.
Also fix the comment style in ip6_expire_frag_queue().
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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The last_in field has been used to store various flags different from
first/last frag in so give it a more descriptive name: flags.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This patch makes init_net's high_thresh limit to be the maximum for all
namespaces, thus introducing a global memory limit threshold equal to the
sum of the individual high_thresh limits which are capped.
It also introduces some sane minimums for low_thresh as it shouldn't be
able to drop below 0 (or > high_thresh in the unsigned case), and
overall low_thresh should not ever be above high_thresh, so we make the
following relations for a namespace:
init_net:
high_thresh - max(not capped), min(init_net low_thresh)
low_thresh - max(init_net high_thresh), min (0)
all other namespaces:
high_thresh = max(init_net high_thresh), min(namespace's low_thresh)
low_thresh = max(namespace's high_thresh), min(0)
The major issue with having low_thresh > high_thresh is that we'll
schedule eviction but never evict anything and thus rely only on the
timers.
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
rehash is rare operation, don't force readers to take
the read-side rwlock.
Instead, we only have to detect the (rare) case where
the secret was altered while we are trying to insert
a new inetfrag queue into the table.
If it was changed, drop the bucket lock and recompute
the hash to get the 'new' chain bucket that we have to
insert into.
Joint work with Nikolay Aleksandrov.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
merge functionality into the eviction workqueue.
Instead of rebuilding every n seconds, take advantage of the upper
hash chain length limit.
If we hit it, mark table for rebuild and schedule workqueue.
To prevent frequent rebuilds when we're completely overloaded,
don't rebuild more than once every 5 seconds.
ipfrag_secret_interval sysctl is now obsolete and has been marked as
deprecated, it still can be changed so scripts won't be broken but it
won't have any effect. A comment is left above each unused secret_timer
variable to avoid confusion.
Joint work with Nikolay Aleksandrov.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
no longer used.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
The 'nqueues' counter is protected by the lru list lock,
once thats removed this needs to be converted to atomic
counter. Given this isn't used for anything except for
reporting it to userspace via /proc, just remove it.
We still report the memory currently used by fragment
reassembly queues.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
When the high_thresh limit is reached we try to toss the 'oldest'
incomplete fragment queues until memory limits are below the low_thresh
value. This happens in softirq/packet processing context.
This has two drawbacks:
1) processors might evict a queue that was about to be completed
by another cpu, because they will compete wrt. resource usage and
resource reclaim.
2) LRU list maintenance is expensive.
But when constantly overloaded, even the 'least recently used' element is
recent, so removing 'lru' queue first is not 'fairer' than removing any
other fragment queue.
This moves eviction out of the fast path:
When the low threshold is reached, a work queue is scheduled
which then iterates over the table and removes the queues that exceed
the memory limits of the namespace. It sets a new flag called
INET_FRAG_EVICTED on the evicted queues so the proper counters will get
incremented when the queue is forcefully expired.
When the high threshold is reached, no more fragment queues are
created until we're below the limit again.
The LRU list is now unused and will be removed in a followup patch.
Joint work with Nikolay Aleksandrov.
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
First step to move eviction handling into a work queue.
We lose two spots that accounted evicted fragments in MIB counters.
Accounting will be restored since the upcoming work-queue evictor
invokes the frag queue timer callbacks instead.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
hide actual hash size from individual users: The _find
function will now fold the given hash value into the required range.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Defrag user check in ip_expire was not updated after adding support for
"conntrack zones".
This bug manifests as a RFC violation, since the router will send
the icmp time exceeeded message when using conntrack zones.
Signed-off-by: Vasily Averin <vvs@openvz.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
|
|
In several places 'skb->rxhash = 0' is being done to clear the
rxhash value in an skb. This does not clear l4_rxhash which could
still be set so that the rxhash wouldn't be recalculated on subsequent
call to skb_get_rxhash. This patch adds an explict function to clear
all the rxhash related information in the skb properly.
skb_clear_hash_if_not_l4 clears the rxhash only if it is not marked as
l4_rxhash.
Fixed up places where 'skb->rxhash = 0' was being called.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Defer the generation of the first hash secret for the ipv4 fragmentation
cache as late as possible.
ip4_frags.rnd gets initial seeded by inet_frags_init and regulary
reseeded by inet_frag_secret_rebuild. Either we call ipqhashfn directly
from ip_fragment.c in which case we initialize the secret directly.
If we first get called by inet_frag_secret_rebuild we install a new secret
by a manual call to get_random_bytes. This secret will be overwritten
as soon as the first call to ipqhashfn happens. This is safe because we
won't race while publishing the new secrets with anyone else.
Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Conflicts:
drivers/net/ethernet/emulex/benet/be_main.c
drivers/net/ethernet/intel/igb/igb_main.c
drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c
include/net/scm.h
net/batman-adv/routing.c
net/ipv4/tcp_input.c
The e{uid,gid} --> {uid,gid} credentials fix conflicted with the
cleanup in net-next to now pass cred structs around.
The be2net driver had a bug fix in 'net' that overlapped with the VLAN
interface changes by Patrick McHardy in net-next.
An IGB conflict existed because in 'net' the build_skb() support was
reverted, and in 'net-next' there was a comment style fix within that
code.
Several batman-adv conflicts were resolved by making sure that all
calls to batadv_is_my_mac() are changed to have a new bat_priv first
argument.
Eric Dumazet's TS ECR fix in TCP in 'net' conflicted with the F-RTO
rewrite in 'net-next', mostly overlapping changes.
Thanks to Stephen Rothwell and Antonio Quartulli for help with several
of these merge resolutions.
Signed-off-by: David S. Miller <davem@davemloft.net>
|
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Commit 4a94445c9a5c (net: Use ip_route_input_noref() in input path)
added a bug in IP defragmentation handling, as non refcounted
dst could escape an RCU protected section.
Commit 64f3b9e203bd068 (net: ip_expire() must revalidate route) fixed
the case of timeouts, but not the general problem.
Tom Parkin noticed crashes in UDP stack and provided a patch,
but further analysis permitted us to pinpoint the root cause.
Before queueing a packet into a frag list, we must drop its dst,
as this dst has limited lifetime (RCU protected)
When/if a packet is finally reassembled, we use the dst of the very
last skb, still protected by RCU and valid, as the dst of the
reassembled packet.
Use same logic in IPv6, as there is no need to hold dst references.
Reported-by: Tom Parkin <tparkin@katalix.com>
Tested-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch just moves some code arround to make the ip4_frag_ecn_table
and IPFRAG_ECN_* constants accessible from the other reassembly engines. I
also renamed ip4_frag_ecn_table to ip_frag_ecn_table.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jesper Dangaard Brouer <jbrouer@redhat.com>
Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch introduces a constant limit of the fragment queue hash
table bucket list lengths. Currently the limit 128 is choosen somewhat
arbitrary and just ensures that we can fill up the fragment cache with
empty packets up to the default ip_frag_high_thresh limits. It should
just protect from list iteration eating considerable amounts of cpu.
If we reach the maximum length in one hash bucket a warning is printed.
This is implemented on the caller side of inet_frag_find to distinguish
between the different users of inet_fragment.c.
I dropped the out of memory warning in the ipv4 fragment lookup path,
because we already get a warning by the slab allocator.
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jesper Dangaard Brouer <jbrouer@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This function will be used in next GRE_GSO patch. This patch does
not change any functionality.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Eric Dumazet <edumazet@google.com>
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Updating the fragmentation queues LRU (Least-Recently-Used) list,
required taking the hash writer lock. However, the LRU list isn't
tied to the hash at all, so we can use a separate lock for it.
Original-idea-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This change is primarily a preparation to ease the extension of memory
limit tracking.
The change does reduce the number atomic operation, during freeing of
a frag queue. This does introduce a some performance improvement, as
these atomic operations are at the core of the performance problems
seen on NUMA systems.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Increase the amount of memory usage limits for incomplete
IP fragments.
Arguing for new thresh high/low values:
High threshold = 4 MBytes
Low threshold = 3 MBytes
The fragmentation memory accounting code, tries to account for the
real memory usage, by measuring both the size of frag queue struct
(inet_frag_queue (ipv4:ipq/ipv6:frag_queue)) and the SKB's truesize.
We want to be able to handle/hold-on-to enough fragments, to ensure
good performance, without causing incomplete fragments to hurt
scalability, by causing the number of inet_frag_queue to grow too much
(resulting longer searches for frag queues).
For IPv4, how much memory does the largest frag consume.
Maximum size fragment is 64K, which is approx 44 fragments with
MTU(1500) sized packets. Sizeof(struct ipq) is 200. A 1500 byte
packet results in a truesize of 2944 (not 2048 as I first assumed)
(44*2944)+200 = 129736 bytes
The current default high thresh of 262144 bytes, is obviously
problematic, as only two 64K fragments can fit in the queue at the
same time.
How many 64K fragment can we fit into 4 MBytes:
4*2^20/((44*2944)+200) = 32.34 fragment in queues
An attacker could send a separate/distinct fake fragment packets per
queue, causing us to allocate one inet_frag_queue per packet, and thus
attacking the hash table and its lists.
How many frag queue do we need to store, and given a current hash size
of 64, what is the average list length.
Using one MTU sized fragment per inet_frag_queue, each consuming
(2944+200) 3144 bytes.
4*2^20/(2944+200) = 1334 frag queues -> 21 avg list length
An attack could send small fragments, the smallest packet I could send
resulted in a truesize of 896 bytes (I'm a little surprised by this).
4*2^20/(896+200) = 3827 frag queues -> 59 avg list length
When increasing these number, we also need to followup with
improvements, that is going to help scalability. Simply increasing
the hash size, is not enough as the current implementation does not
have a per hash bucket locking.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet
Nikolay Borisov
Joe Stringer
Florian Westphal
Eric W. Biederman
David Ahern
David S. Miller
Nikolay Aleksandrov
Edward Hyunkoo Jee
Andy Zhou
Ian Morris
Alexander Drozdov
Joe Perches
Fabian Frederick
Nikolay Aleksandrov
Vasily Averin
Tom Herbert
Hannes Frederic Sowa
Pravin B Shelar
Jesper Dangaard Brouer