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David Lebrun af3b5158b8 ipv6: sr: fix BUG due to headroom too small after SRH push
When a locally generated packet receives an SRH with two or more segments,
the remaining headroom is too small to push an ethernet header. This patch
ensures that the headroom is large enough after SRH push.

The BUG generated the following trace.

[  192.950285] skbuff: skb_under_panic: text:ffffffff81809675 len:198 put:14 head:ffff88006f306400 data:ffff88006f3063fa tail:0xc0 end:0x2c0 dev:A-1
[  192.952456] ------------[ cut here ]------------
[  192.953218] kernel BUG at net/core/skbuff.c:105!
[  192.953411] invalid opcode: 0000 [#1] PREEMPT SMP
[  192.953411] Modules linked in:
[  192.953411] CPU: 5 PID: 3433 Comm: ping6 Not tainted 4.11.0-rc3+ #237
[  192.953411] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014
[  192.953411] task: ffff88007c2d42c0 task.stack: ffffc90000ef4000
[  192.953411] RIP: 0010:skb_panic+0x61/0x70
[  192.953411] RSP: 0018:ffffc90000ef7900 EFLAGS: 00010286
[  192.953411] RAX: 0000000000000085 RBX: 00000000000086dd RCX: 0000000000000201
[  192.953411] RDX: 0000000080000201 RSI: ffffffff81d104c5 RDI: 00000000ffffffff
[  192.953411] RBP: ffffc90000ef7920 R08: 0000000000000001 R09: 0000000000000000
[  192.953411] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[  192.953411] R13: ffff88007c5a4000 R14: ffff88007b363d80 R15: 00000000000000b8
[  192.953411] FS:  00007f94b558b700(0000) GS:ffff88007fd40000(0000) knlGS:0000000000000000
[  192.953411] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  192.953411] CR2: 00007fff5ecd5080 CR3: 0000000074141000 CR4: 00000000001406e0
[  192.953411] Call Trace:
[  192.953411]  skb_push+0x3b/0x40
[  192.953411]  eth_header+0x25/0xc0
[  192.953411]  neigh_resolve_output+0x168/0x230
[  192.953411]  ? ip6_finish_output2+0x242/0x8f0
[  192.953411]  ip6_finish_output2+0x242/0x8f0
[  192.953411]  ? ip6_finish_output2+0x76/0x8f0
[  192.953411]  ip6_finish_output+0xa8/0x1d0
[  192.953411]  ip6_output+0x64/0x2d0
[  192.953411]  ? ip6_output+0x73/0x2d0
[  192.953411]  ? ip6_dst_check+0xb5/0xc0
[  192.953411]  ? dst_cache_per_cpu_get.isra.2+0x40/0x80
[  192.953411]  seg6_output+0xb0/0x220
[  192.953411]  lwtunnel_output+0xcf/0x210
[  192.953411]  ? lwtunnel_output+0x59/0x210
[  192.953411]  ip6_local_out+0x38/0x70
[  192.953411]  ip6_send_skb+0x2a/0xb0
[  192.953411]  ip6_push_pending_frames+0x48/0x50
[  192.953411]  rawv6_sendmsg+0xa39/0xf10
[  192.953411]  ? __lock_acquire+0x489/0x890
[  192.953411]  ? __mutex_lock+0x1fc/0x970
[  192.953411]  ? __lock_acquire+0x489/0x890
[  192.953411]  ? __mutex_lock+0x1fc/0x970
[  192.953411]  ? tty_ioctl+0x283/0xec0
[  192.953411]  inet_sendmsg+0x45/0x1d0
[  192.953411]  ? _copy_from_user+0x54/0x80
[  192.953411]  sock_sendmsg+0x33/0x40
[  192.953411]  SYSC_sendto+0xef/0x170
[  192.953411]  ? entry_SYSCALL_64_fastpath+0x5/0xc2
[  192.953411]  ? trace_hardirqs_on_caller+0x12b/0x1b0
[  192.953411]  ? trace_hardirqs_on_thunk+0x1a/0x1c
[  192.953411]  SyS_sendto+0x9/0x10
[  192.953411]  entry_SYSCALL_64_fastpath+0x1f/0xc2
[  192.953411] RIP: 0033:0x7f94b453db33
[  192.953411] RSP: 002b:00007fff5ecd0578 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
[  192.953411] RAX: ffffffffffffffda RBX: 00007fff5ecd16e0 RCX: 00007f94b453db33
[  192.953411] RDX: 0000000000000040 RSI: 000055a78352e9c0 RDI: 0000000000000003
[  192.953411] RBP: 00007fff5ecd1690 R08: 000055a78352c940 R09: 000000000000001c
[  192.953411] R10: 0000000000000000 R11: 0000000000000246 R12: 000055a783321e10
[  192.953411] R13: 000055a7839890c0 R14: 0000000000000004 R15: 0000000000000000
[  192.953411] Code: 00 00 48 89 44 24 10 8b 87 c4 00 00 00 48 89 44 24 08 48 8b 87 d8 00 00 00 48 c7 c7 90 58 d2 81 48 89 04 24 31 c0 e8 4f 70 9a ff <0f> 0b 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 48 8b 97 d8 00 00
[  192.953411] RIP: skb_panic+0x61/0x70 RSP: ffffc90000ef7900
[  193.000186] ---[ end trace bd0b89fabdf2f92c ]---
[  193.000951] Kernel panic - not syncing: Fatal exception in interrupt
[  193.001137] Kernel Offset: disabled
[  193.001169] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

Fixes: 19d5a26f5e ("ipv6: sr: expand skb head only if necessary")
Signed-off-by: David Lebrun <david.lebrun@uclouvain.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-17 15:33:53 -04:00
arch Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2017-04-17 15:00:57 -04:00
block blk-mq: Restart a single queue if tag sets are shared 2017-04-07 12:40:09 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto netlink: pass extended ACK struct where available 2017-04-13 13:58:22 -04:00
Documentation Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2017-04-17 15:00:57 -04:00
drivers hv_netvsc: change netvsc device default duplex to FULL 2017-04-17 15:12:33 -04:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-04-15 21:16:30 -04:00
include Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2017-04-17 15:00:57 -04:00
init mm: move mm_percpu_wq initialization earlier 2017-03-31 17:13:30 -07:00
ipc Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
kernel bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-04-15 21:16:30 -04:00
mm zsmalloc: expand class bit 2017-04-13 18:24:21 -07:00
net ipv6: sr: fix BUG due to headroom too small after SRH push 2017-04-17 15:33:53 -04:00
samples bpf: lru: Add map-in-map LRU example 2017-04-17 13:55:52 -04:00
scripts Kbuild fixes for v4.11 2017-04-05 08:37:28 -07:00
security rtnetlink: Add RTM_DELNETCONF 2017-03-28 22:32:42 -07:00
sound ALSA: hda - fix a problem for lineout on a Dell AIO machine 2017-03-31 10:58:26 +02:00
tools bpf: lru: Lower the PERCPU_NR_SCANS from 16 to 4 2017-04-17 13:55:52 -04:00
usr kbuild: initramfs cleanup, set target from Kconfig 2017-01-05 09:40:16 -08:00
virt KVM/ARM Fixes for v4.11-rc6 2017-04-05 16:27:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Merge branch 'misc' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2016-08-02 16:48:52 -04:00
.mailmap mailmap: add Martin Kepplinger's email 2017-04-13 18:24:21 -07:00
COPYING
CREDITS MAINTAINERS: Remove old e-mail address 2017-02-13 12:24:56 -05:00
Kbuild scripts/gdb: provide linux constants 2016-05-23 17:04:14 -07:00
Kconfig
MAINTAINERS Merge branch 'for-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next 2017-04-17 15:00:57 -04:00
Makefile Linux 4.11-rc6 2017-04-09 09:49:44 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.