Messages in this thread | | | Date | Thu, 28 Jan 2016 09:15:09 -0800 | Subject | 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 | From | Alexander Duyck <> |
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On Tue, Jan 26, 2016 at 1:36 PM, Eric Dumazet <eric.dumazet@gmail.com> 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
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