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Eric W. Biederman b9f75f45a6 netns: Don't receive new packets in a dead network namespace. 
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>
 		2008-06-20 22:16:51 -07:00
..
acpi proper prototype for acpi_processor_tstate_has_changed() 2008-06-11 19:13:46 -04:00
asm-alpha
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asm-arm [ARM] 5091/1: Add missing bitfield include to regs-lcd.h 2008-06-12 20:49:38 +01:00
asm-avr32
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asm-blackfin Blackfin Serial Driver: Clean up BF54x macro in blackfin UART driver. 2008-06-03 12:19:45 +08:00
asm-cris
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asm-frv FRV: ip_fast_csum() requires a memory clobber on its inline asm 2008-06-05 10:31:21 -07:00
asm-generic gpio: build fixes 2008-05-24 09:56:13 -07:00
asm-h8300 h8300: fix typo in header guard 2008-06-06 11:29:12 -07:00
asm-ia64 [IA64] Workaround for RSE issue 2008-05-27 13:24:39 -07:00
asm-m32r asm-m32r/uaccess.h must #include <asm/setup.h> 2008-06-06 11:29:13 -07:00
asm-m68k m68k: Add ext2_find_{first,next}_bit() for ext4 2008-06-12 18:05:39 -07:00
asm-m68knommu
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asm-mips [MIPS] Fix typo in header guard 2008-06-05 18:13:16 +01:00
asm-mn10300 MN10300: Fix typo in header guard 2008-05-28 07:59:06 -07:00
asm-parisc parisc: fix miscompilation of ip_fast_csum with gcc >= 4.3 2008-06-13 10:49:56 -04:00
asm-powerpc KVM: ppc: Remove duplicate function 2008-06-06 21:22:09 +03:00
asm-ppc
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asm-s390 [S390] Fix __ctl_load/__ctl_store inline assembly constraints 2008-06-10 10:03:28 +02:00
asm-sh sh: fix miscompilation of ip_fast_csum with gcc >= 4.3 2008-06-02 12:40:14 +09:00
asm-sparc sparc: remove CVS keywords 2008-05-20 00:33:44 -07:00
asm-sparc64 sparc64: IO accessors fix 2008-05-30 02:01:28 -07:00
asm-um uml: activate_mm: remove the dead PF_BORROWED_MM check 2008-06-06 11:36:22 -07:00
asm-v850 v850: fix typo in header guard 2008-06-06 11:29:12 -07:00
asm-x86 x86: fix broken math-emu with lazy allocation of fpu area 2008-06-04 13:11:46 +02:00
asm-xtensa
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crypto
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keys
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linux ipv6 sit: Avoid extra need for compat layer in PRL management. 2008-06-16 16:48:20 -07:00
math-emu
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media V4L/DVB (7911): Remove v4l2_video_std_fps prototype declaration 2008-06-05 06:35:42 -03:00
mtd
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net netns: Don't receive new packets in a dead network namespace. 2008-06-20 22:16:51 -07:00
pcmcia
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rdma IB/core: Remove IB_DEVICE_SEND_W_INV capability flag 2008-06-09 09:58:42 -07:00
rxrpc
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scsi
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sound [ALSA] ac97 - Fix ASUS A9T laptop output 2008-05-30 16:20:42 +02:00
video
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xen
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Kbuild
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