Fw: iproute2: segfault with ip link show dev

[Stephen Hemminger <stephen@networkplumber.org>]

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Looks like one VF info changes broke old code

Begin forwarded message:

Date: Wed, 7 Jan 2015 04:06:53 -0800
From: William Dauchy <william@gandi.net>
To: "stephen@networkplumber.org" <stephen@networkplumber.org>
Subject: iproute2: segfault with ip link show dev


Hi,

I was using iproute2 3.15.
My network card in using igb driver with VF enable, e.g igb.max_vfs=2
After upgrading to 3.16, I have now a segfault while doing a
usual `ip link show dev eth1`.
Disabling VFS make the segafult disappear.

Here is the gdb trace even if it does not contain much info.
The segfault occurs when at the VF step.

(gdb) break print_linkinfo
Breakpoint 1 at 0x40782d
(gdb) set args link show dev eth1
(gdb) r
Starting program: /sbin/ip link show dev eth1

Breakpoint 1, 0x000000000040782d in print_linkinfo ()
(gdb) n
Single stepping until exit from function print_linkinfo,
which has no line number information.
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc mq state UP
mode DEFAULT group default qlen 10000
    link/ether 00:26:6c:ff:b5:c1 brd ff:ff:ff:ff:ff:ff

Program received signal SIGSEGV, Segmentation fault.
0x00000000004070eb in print_vfinfo ()
(gdb) bt
#0  0x00000000004070eb in print_vfinfo ()
#1  0x0000000000407f9f in print_linkinfo ()
#2  0x000000000041f266 in iplink_get ()
#3  0x0000000000409c69 in ipaddr_list_flush_or_save ()
#4  0x000000000040a113 in ipaddr_list_link ()
#5  0x00000000004203f6 in do_iplink ()
#6  0x0000000000405a07 in do_cmd ()
#7  0x000000000040621e in main ()

The expected output is for example:

# ip link show dev eth1
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc mq state UP mode DEFAULT group default qlen 10000
    link/ether 00:26:6c:ff:b3:8d brd ff:ff:ff:ff:ff:ff
    vf 0 MAC 00:00:00:00:00:00, spoof checking on, link-state auto
    vf 1 MAC 00:00:00:00:00:00, spoof checking on, link-state auto


I'm using my own kernel build, a stable v3.14.x

Regards,
-- 
William

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