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2008-06-21netns: Don't receive new packets in a dead network namespace.Eric W. Biederman1-0/+3
Alexey Dobriyan <adobriyan@gmail.com> writes: > Subject: ICMP sockets destruction vs ICMP packets oops > After icmp_sk_exit() nuked ICMP sockets, we get an interrupt. > icmp_reply() wants ICMP socket. > > Steps to reproduce: > > launch shell in new netns > move real NIC to netns > setup routing > ping -i 0 > exit from shell > > BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 > IP: [<ffffffff803fce17>] icmp_sk+0x17/0x30 > PGD 17f3cd067 PUD 17f3ce067 PMD 0 > Oops: 0000 [1] PREEMPT SMP DEBUG_PAGEALLOC > CPU 0 > Modules linked in: usblp usbcore > Pid: 0, comm: swapper Not tainted 2.6.26-rc6-netns-ct #4 > RIP: 0010:[<ffffffff803fce17>] [<ffffffff803fce17>] icmp_sk+0x17/0x30 > RSP: 0018:ffffffff8057fc30 EFLAGS: 00010286 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff81017c7db900 > RDX: 0000000000000034 RSI: ffff81017c7db900 RDI: ffff81017dc41800 > RBP: ffffffff8057fc40 R08: 0000000000000001 R09: 000000000000a815 > R10: 0000000000000000 R11: 0000000000000001 R12: ffffffff8057fd28 > R13: ffffffff8057fd00 R14: ffff81017c7db938 R15: ffff81017dc41800 > FS: 0000000000000000(0000) GS:ffffffff80525000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > CR2: 0000000000000000 CR3: 000000017fcda000 CR4: 00000000000006e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > Process swapper (pid: 0, threadinfo ffffffff8053a000, task ffffffff804fa4a0) > Stack: 0000000000000000 ffff81017c7db900 ffffffff8057fcf0 ffffffff803fcfe4 > ffffffff804faa38 0000000000000246 0000000000005a40 0000000000000246 > 000000000001ffff ffff81017dd68dc0 0000000000005a40 0000000055342436 > Call Trace: > <IRQ> [<ffffffff803fcfe4>] icmp_reply+0x44/0x1e0 > [<ffffffff803d3a0a>] ? ip_route_input+0x23a/0x1360 > [<ffffffff803fd645>] icmp_echo+0x65/0x70 > [<ffffffff803fd300>] icmp_rcv+0x180/0x1b0 > [<ffffffff803d6d84>] ip_local_deliver+0xf4/0x1f0 > [<ffffffff803d71bb>] ip_rcv+0x33b/0x650 > [<ffffffff803bb16a>] netif_receive_skb+0x27a/0x340 > [<ffffffff803be57d>] process_backlog+0x9d/0x100 > [<ffffffff803bdd4d>] net_rx_action+0x18d/0x250 > [<ffffffff80237be5>] __do_softirq+0x75/0x100 > [<ffffffff8020c97c>] call_softirq+0x1c/0x30 > [<ffffffff8020f085>] do_softirq+0x65/0xa0 > [<ffffffff80237af7>] irq_exit+0x97/0xa0 > [<ffffffff8020f198>] do_IRQ+0xa8/0x130 > [<ffffffff80212ee0>] ? mwait_idle+0x0/0x60 > [<ffffffff8020bc46>] ret_from_intr+0x0/0xf > <EOI> [<ffffffff80212f2c>] ? mwait_idle+0x4c/0x60 > [<ffffffff80212f23>] ? mwait_idle+0x43/0x60 > [<ffffffff8020a217>] ? cpu_idle+0x57/0xa0 > [<ffffffff8040f380>] ? rest_init+0x70/0x80 > Code: 10 5b 41 5c 41 5d 41 5e c9 c3 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 > 48 83 ec 08 48 8b 9f 78 01 00 00 e8 2b c7 f1 ff 89 c0 <48> 8b 04 c3 48 83 c4 08 > 5b c9 c3 66 66 66 66 66 2e 0f 1f 84 00 > RIP [<ffffffff803fce17>] icmp_sk+0x17/0x30 > RSP <ffffffff8057fc30> > CR2: 0000000000000000 > ---[ end trace ea161157b76b33e8 ]--- > Kernel panic - not syncing: Aiee, killing interrupt handler! Receiving packets while we are cleaning up a network namespace is a racy proposition. It is possible when the packet arrives that we have removed some but not all of the state we need to fully process it. We have the choice of either playing wack-a-mole with the cleanup routines or simply dropping packets when we don't have a network namespace to handle them. Since the check looks inexpensive in netif_receive_skb let's just drop the incoming packets. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-16[NETNS]: Make netns refconting debug like a socket one.Denis V. Lunev1-0/+4
Make release_net/hold_net noop for performance-hungry people. This is a debug staff and should be used in the debug mode only. Add check for net != NULL in hold/release calls. This will be required later on. [ Added minor simplifications suggested by Brian Haley. -DaveM ] Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-15[NETNS]: The generic per-net pointers.Pavel Emelyanov1-0/+62
Add the elastic array of void * pointer to the struct net. The access rules are simple: 1. register the ops with register_pernet_gen_device to get the id of your private pointer 2. call net_assign_generic() to put the private data on the struct net (most preferably this should be done in the ->init callback of the ops registered) 3. do not store any private reference on the net_generic array; 4. do not change this pointer while the net is alive; 5. use the net_generic() to get the pointer. When adding a new pointer, I copy the old array, replace it with a new one and schedule the old for kfree after an RCU grace period. Since the net_generic explores the net->gen array inside rcu read section and once set the net->gen->ptr[x] pointer never changes, this grants us a safe access to generic pointers. Quoting Paul: "... RCU is protecting -only- the net_generic structure that net_generic() is traversing, and the [pointer] returned by net_generic() is protected by a reference counter in the upper-level struct net." Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-04-15[NETNS]: The net-subsys IDs generator.Pavel Emelyanov1-0/+38
To make some per-net generic pointers, we need some way to address them, i.e. - IDs. This is simple IDA-based IDs generator for pernet subsystems. Addressing questions about potential checkpoint/restart problems: these IDs are "lite-offsets" within the net structure and are by no means supposed to be exported to the userspace. Since it will be used in the nearest future by devices only (tun, vlan, tunnels, bridge, etc), I make it resemble the functionality of register_pernet_device(). The new ids is stored in the *id pointer _before_ calling the init callback to make this id available in this callback. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-02-03typo fixes in net/core/net_namespace.cOliver Pinter1-2/+2
Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com> Signed-off-by: Adrian Bunk <bunk@kernel.org>
2008-01-29[NET]: Make netns cleanup to run in a separate queueBenjamin Thery1-1/+8
This patch adds a separate workqueue for cleaning up a network namespace. If we use the keventd workqueue to execute cleanup_net(), there is a problem to unregister devices in IPv6. Indeed the code that cleans up also schedule work in keventd: as long as cleanup_net() hasn't return, dst_gc_task() cannot run and as long as dst_gc_task() has not run, there are still some references pending on the net devices and cleanup_net() can not unregister and exit the keventd workqueue. Signed-off-by: Benjamin Thery <benjamin.thery@bull.net> Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Acked-by: Denis V. Lunev <den@openvz.org> Acked-By: Kirill Korotaev <dev@sw.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-01-23[NETNS]: Re-export init_net via EXPORT_SYMBOL.Denis V. Lunev1-1/+1
init_net is used added as a parameter to a lot of old API calls, f.e. ip_dev_find. These calls were exported as EXPORT_SYMBOL. So, export init_net as EXPORT_SYMBOL to keep networking API consistent. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-13[NET]: Cleanup pernet operation without CONFIG_NET_NSDenis V. Lunev1-0/+18
If CONFIG_NET_NS is not set, the only namespace is possible. This patch removes list of pernet_operations and cleanups code a bit. This list is not needed if there are no namespaces. We should just call ->init method. Additionally, the ->exit will be called on module unloading only. This case is safe - the code is not discarded. For the in/kernel code, ->exit should never be called. Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-07[NETNS]: Fix compiler error in net_namespace.cJohann Felix Soden1-14/+14
Because net_free is called by copy_net_ns before its declaration, the compiler gives an error. This patch puts net_free before copy_net_ns to fix this. The compiler error: net/core/net_namespace.c: In function 'copy_net_ns': net/core/net_namespace.c:97: error: implicit declaration of function 'net_free' net/core/net_namespace.c: At top level: net/core/net_namespace.c:104: warning: conflicting types for 'net_free' net/core/net_namespace.c:104: error: static declaration of 'net_free' follows non-static declaration net/core/net_namespace.c:97: error: previous implicit declaration of 'net_free' was here The error was introduced by the '[NET]: Hide the dead code in the net_namespace.c' patch (6a1a3b9f686bb04820a232cc1657ef2c45670709). Signed-off-by: Johann Felix Soden <johfel@users.sourceforge.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-01[NET]: Hide the net_ns kmem cachePavel Emelyanov1-2/+4
This cache is only required to create new namespaces, but we won't have them in CONFIG_NET_NS=n case. Hide it under the appropriate ifdef. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-01[NET]: Mark the setup_net as __net_initPavel Emelyanov1-1/+1
The setup_net is called for the init net namespace only (int the CONFIG_NET_NS=n of course) from the __init function, so mark it as __net_init to disappear with the caller after the boot. Yet again, in the perfect world this has to be under #ifdef CONFIG_NET_NS, but it isn't guaranteed that every subsystem is registered *after* the init_net_ns is set up. After we are sure, that we don't start registering them before the init net setup, we'll be able to move this code under the ifdef. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-01[NET]: Hide the dead code in the net_namespace.cPavel Emelyanov1-63/+68
The namespace creation/destruction code is never called if the CONFIG_NET_NS is n, so it's OK to move it under appropriate ifdef. The copy_net_ns() in the "n" case checks for flags and returns -EINVAL when new net ns is requested. In a perfect world this stub must be in net_namespace.h, but this function need to know the CLONE_NEWNET value and thus requires sched.h. On the other hand this header is to be injected into almost every .c file in the networking code, and making all this code depend on the sched.h is a suicidal attempt. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-11-01[NETNS]: Make the init/exit hooks checks outside the loopPavel Emelyanov1-12/+11
When the new pernet something (subsys, device or operations) is being registered, the init callback is to be called for each namespace, that currently exitst in the system. During the unregister, the same is to be done with the exit callback. However, not every pernet something has both calls, but the check for the appropriate pointer to be not NULL is performed inside the for_each_net() loop. This is (at least) strange, so tune this. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-31[NETNS]: fix net released by rcu callbackDaniel Lezcano1-0/+2
When a network namespace reference is held by a network subsystem, and when this reference is decremented in a rcu update callback, we must ensure that there is no more outstanding rcu update before trying to free the network namespace. In the normal case, the rcu_barrier is called when the network namespace is exiting in the cleanup_net function. But when a network namespace creation fails, and the subsystems are undone (like the cleanup), the rcu_barrier is missing. This patch adds the missing rcu_barrier. Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NETNS]: Don't memset() netns to zero manuallyPavel Emelyanov1-2/+1
The newly created net namespace is set to 0 with memset() in setup_net(). The setup_net() is also called for the init_net_ns(), which is zeroed naturally as a global var. So remove this memset and allocate new nets with the kmem_cache_zalloc(). Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NETNS]: Simplify the network namespace list locking rules.Eric W. Biederman1-17/+6
Denis V. Lunev <den@sw.ru> noticed that the locking rules for the network namespace list are over complicated and broken. In particular the current register_netdev_notifier currently does not take any lock making the for_each_net iteration racy with network namespace creation and destruction. Oops. The fact that we need to use for_each_net in rtnl_unlock() when the rtnetlink support becomes per network namespace makes designing the proper locking tricky. In addition we need to be able to call rtnl_lock() and rtnl_unlock() when we have the net_mutex held. After thinking about it and looking at the alternatives carefully it looks like the simplest and most maintainable solution is to remove net_list_mutex altogether, and to use the rtnl_mutex instead. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET]: Add network namespace clone & unshare support.Eric W. Biederman1-2/+41
This patch allows you to create a new network namespace using sys_clone, or sys_unshare. As the network namespace is still experimental and under development clone and unshare support is only made available when CONFIG_NET_NS is selected at compile time. As this patch introduces network namespace support into code paths that exist when the CONFIG_NET is not selected there are a few additions made to net_namespace.h to allow a few more functions to be used when the networking stack is not compiled in. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NETNS]: Cleanup list walking in setup_net and cleanup_netPavel Emelyanov1-8/+4
I proposed introducing a list_for_each_entry_continue_reverse macro to be used in setup_net() when unrolling the failed ->init callback. Here is the macro and some more cleanup in the setup_net() itself to remove one variable from the stack :) The same thing is for the cleanup_net() - the existing list_for_each_entry_reverse() is used. Minor, but the code looks nicer. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET]: #if 0 out net_alloc() for now.David S. Miller1-0/+2
We will undo this once it is actually used. Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-11[NET]: Basic network namespace infrastructure.Eric W. Biederman1-0/+292
This is the basic infrastructure needed to support network namespaces. This infrastructure is: - Registration functions to support initializing per network namespace data when a network namespaces is created or destroyed. - struct net. The network namespace data structure. This structure will grow as variables are made per network namespace but this is the minimal starting point. - Functions to grab a reference to the network namespace. I provide both get/put functions that keep a network namespace from being freed. And hold/release functions serve as weak references and will warn if their count is not zero when the data structure is freed. Useful for dealing with more complicated data structures like the ipv4 route cache. - A list of all of the network namespaces so we can iterate over them. - A slab for the network namespace data structure allowing leaks to be spotted. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>