Re: UBSAN: Undefined behaviour in net/ipv4/fib_trie.c:1397:22 and UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:2
On Tue, Jan 26, 2016 at 1:36 PM, Eric Dumazet wrote:
> On Tue, 2016-01-26 at 20:45 +0100, Toralf Förster wrote:
>> at a 32 nbit KVM image of a Gentoo Linux runniogn v4.5-rc1 - attached is
>> /var/log/messages
>>
>
> Jan 26 20:40:04 n22kvm-clone kernel:
>
> Jan 26 20:40:04 n22kvm-clone kernel: UBSAN: Undefined behaviour in
> net/ipv4/fib_trie.c:1397:22
> Jan 26 20:40:04 n22kvm-clone kernel: shift exponent 32 is too large for
> 32-bit type 'long unsigned int'
> Jan 26 20:40:04 n22kvm-clone kernel: CPU: 1 PID: 2050 Comm: dhcpcd Not
> tainted 4.5.0-rc1 #1
> Jan 26 20:40:04 n22kvm-clone kernel: Hardware name: QEMU Standard PC (i440FX
> + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
>
> Thanks for the report.
>
> CC netdev and Alexander
>
> Commit 79e5ad2ceb006
> ("fib_trie: Remove leaf_info ")
I looked over the line in question, it is an issue where we are doing
the shift and then sanitizing for the undefined result after the fact.
I'll see about submitting a patch to address this.
- Alex
Re: UBSAN: Undefined behaviour in net/ipv4/fib_trie.c:1397:22 and UBSAN: Undefined behaviour in ./arch/x86/include/asm/atomic.h:156:2
On Tue, 2016-01-26 at 20:45 +0100, Toralf Förster wrote:
> at a 32 nbit KVM image of a Gentoo Linux runniogn v4.5-rc1 - attached is
> /var/log/messages
>
Jan 26 20:40:04 n22kvm-clone kernel:
Jan 26 20:40:04 n22kvm-clone kernel: UBSAN: Undefined behaviour in
net/ipv4/fib_trie.c:1397:22
Jan 26 20:40:04 n22kvm-clone kernel: shift exponent 32 is too large for 32-bit
type 'long unsigned int'
Jan 26 20:40:04 n22kvm-clone kernel: CPU: 1 PID: 2050 Comm: dhcpcd Not tainted
4.5.0-rc1 #1
Jan 26 20:40:04 n22kvm-clone kernel: Hardware name: QEMU Standard PC (i440FX +
PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
Thanks for the report.
CC netdev and Alexander
Commit 79e5ad2ceb006
("fib_trie: Remove leaf_info ")
