Messages in this thread | | | Date | Mon, 8 Jun 2009 15:06:53 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH net-next-2.6] net: dev_addr_init() fix |
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* Eric Dumazet <dada1@cosmosbay.com> wrote:
> Eric Dumazet a écrit : > > Vegard Nossum a écrit : > >> 2009/6/7 John Dykstra <john.dykstra1@gmail.com>: > >>> On Sat, 2009-05-30 at 22:23 +0200, Vegard Nossum wrote: > >>>> It seems that loopback's hardware address is never initialized by the > >>>> kernel. So if userspace attempts to read this address before it has > >>>> been set, the kernel will return some uninitialized data (only 6 > >>>> bytes, though). > >>> Thank you for the report, Vegard. > >>> > >>> I've been unable to reproduce the problem you describe, using > >>> 2.6-30-rc8, this test program and a couple of kernel builds for system > >>> load: > >> [...] > >>> ------------------------------------------------------------------ > >>> > >>> Looking at the kernel code, it appears that all bytes of struct > >>> net_device, including the L2 address, are initialized to zeros at > >>> interface creation time. > >>> > >>> Can you spot a difference between your test procedures and mine that > >>> would enable me to reproduce the problem? > >> Hi, > >> > >> I just tried your test program on a linux-next kernel, it works beautifully :-) > >> > >> (I made one change: The stack grows downwards on x86, so I think you > >> should put child_stack + 16386 as the stack to clone()?) > >> > >> As I wrote in reply to Stephen Hemminger, this problem seems to be > >> caused by a particular patch in linux-next: > >> > >> commit f001fde5eadd915f4858d22ed70d7040f48767cf > >> Author: Jiri Pirko <jpirko@redhat.com> > >> Date: Tue May 5 02:48:28 2009 +0000 > >> > >> net: introduce a list of device addresses dev_addr_list (v6) > >> > > > > I believe following patch should fix this problem. > > > > Thank you > > > > [PATCH net-next-2.6] net: loopback device dev->addr_len fix > > > > commit f001fde5eadd915f4858d22ed70d7040f48767cf > > (net: introduce a list of device addresses dev_addr_list (v6)) > > added one regression Vegard Nossum found in its testings. > > > > loopback device doesnt have a hw address, we should set its > > dev->addr_len to 0, not ETH_ALEN. > > > > Reported-by: Vegard Nossum <vegard.nossum@gmail.com> > > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> > > Oh well, following is probably even more appropriate > > [PATCH net-next-2.6] net: dev_addr_init() fix > > commit f001fde5eadd915f4858d22ed70d7040f48767cf > (net: introduce a list of device addresses dev_addr_list (v6)) > added one regression Vegard Nossum found in its testings. > > dev_addr_init() incorrectly uses sizeof() operator > > Reported-by: Vegard Nossum <vegard.nossum@gmail.com> > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Could you please put the word 'kmemcheck' somewhere into the changelog, to make git-grepping and historic comparisons easier?
Thanks,
Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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