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Paolo Abeni 19cdead3e2 bonding: avoid defaulting hard_header_len to ETH_HLEN on slave removal
On slave list updates, the bonding driver computes its hard_header_len
as the maximum of all enslaved devices's hard_header_len.
If the slave list is empty, e.g. on last enslaved device removal,
ETH_HLEN is used.

Since the bonding header_ops are set only when the first enslaved
device is attached, the above can lead to header_ops->create()
being called with the wrong skb headroom in place.

If bond0 is configured on top of ipoib devices, with the
following commands:

ifup bond0
for slave in $BOND_SLAVES_LIST; do
	ip link set dev $slave nomaster
done
ping -c 1 <ip on bond0 subnet>

we will obtain a skb_under_panic() with a similar call trace:
	skb_push+0x3d/0x40
	push_pseudo_header+0x17/0x30 [ib_ipoib]
	ipoib_hard_header+0x4e/0x80 [ib_ipoib]
	arp_create+0x12f/0x220
	arp_send_dst.part.19+0x28/0x50
	arp_solicit+0x115/0x290
	neigh_probe+0x4d/0x70
	__neigh_event_send+0xa7/0x230
	neigh_resolve_output+0x12e/0x1c0
	ip_finish_output2+0x14b/0x390
	ip_finish_output+0x136/0x1e0
	ip_output+0x76/0xe0
	ip_local_out+0x35/0x40
	ip_send_skb+0x19/0x40
	ip_push_pending_frames+0x33/0x40
	raw_sendmsg+0x7d3/0xb50
	inet_sendmsg+0x31/0xb0
	sock_sendmsg+0x38/0x50
	SYSC_sendto+0x102/0x190
	SyS_sendto+0xe/0x10
	do_syscall_64+0x67/0x180
	entry_SYSCALL64_slow_path+0x25/0x25

This change addresses the issue avoiding updating the bonding device
hard_header_len when the slaves list become empty, forbidding to
shrink it below the value used by header_ops->create().

The bug is there since commit 54ef313714 ("[PATCH] bonding: Handle large
hard_header_len") but the panic can be triggered only since
commit fc791b6335 ("IB/ipoib: move back IB LL address into the hard
header").

Reported-by: Norbert P <noe@physik.uzh.ch>
Fixes: 54ef313714 ("[PATCH] bonding: Handle large hard_header_len")
Fixes: fc791b6335 ("IB/ipoib: move back IB LL address into the hard header")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-04-28 16:04:05 -04:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc 2017-04-26 15:10:45 -07:00
block blk-mq: fix potential oops with polling and blk-mq scheduler 2017-04-20 14:53:28 -06:00
certs certs: Add a secondary system keyring that can be added to dynamically 2016-04-11 22:48:09 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2017-04-18 09:03:50 -07:00
Documentation pci-v4.11-fixes-5 2017-04-21 09:26:34 -07:00
drivers bonding: avoid defaulting hard_header_len to ETH_HLEN on slave removal 2017-04-28 16:04:05 -04:00
firmware WHENCE: use https://linuxtv.org for LinuxTV URLs 2015-12-04 10:35:11 -02:00
fs statx: Kill fd-with-NULL-path support in favour of AT_EMPTY_PATH 2017-04-26 15:05:47 -07:00
include net: phy: fix auto-negotiation stall due to unavailable interrupt 2017-04-26 14:32:00 -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 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-04-23 12:48:05 -07:00
lib sparc64: Use LOCKDEP_SMALL, not PROVE_LOCKING_SMALL 2017-04-18 13:11:07 -07:00
mm mm: prevent NR_ISOLATE_* stats from going negative 2017-04-20 15:30:18 -07:00
net ipv4: Don't pass IP fragments to upper layer GRO handlers. 2017-04-28 16:00:38 -04:00
samples statx: Include a mask for stx_attributes in struct statx 2017-04-03 01:06:00 -04:00
scripts Kbuild fixes for v4.11 2017-04-05 08:37:28 -07:00
security KEYS: fix keyctl_set_reqkey_keyring() to not leak thread keyrings 2017-04-18 15:31:49 +01:00
sound ASoC: Fixes for v4.11 2017-04-25 17:43:56 +02:00
tools bpf: Fix values type used in test_maps 2017-04-21 15:16:46 -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 bpf, doc: update bpf maintainers entry 2017-04-21 15:25:10 -04:00
Makefile Linux 4.11-rc8 2017-04-23 16:53:00 -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.