New: EV6 version of csum_ipv6_magic causing unaligned access errors

Bugme-new Andrew Morton 2 participants 2 messages Jun 16, 2007 1 message not in the archive

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Andrew Morton

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2007-06-16 07:06 UTC #1 lore raw

Quoted 52 lines · On Fri, 15 Jun 2007 13:47:33 -0700 (PDT) [email protected] wrote:

http://bugzilla.kernel.org/show_bug.cgi?id=8635
           Summary: EV6 version of csum_ipv6_magic causing unaligned access
                    errors
           Product: Networking
           Version: 2.5
     KernelVersion: 2.6.18 & 2.6.22-rc4-mm2
          Platform: All
        OS/Version: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: IPV6
        AssignedTo: [email protected]
        ReportedBy: [email protected]
Most recent kernel where this bug did not occur: Unknown (Sorry!)
Distribution: Debian/testing (lenny)
Hardware Environment: API Networks CS20 (2 x 833Mhz 21264B Alpha CPUs) Software Environment:
Linux sky 2.6.22-rc4-mm2 #1 SMP Tue Jun 12 23:00:10 CDT 2007 alpha GNU/Linux
Gnu C                  4.2.1
Gnu make               3.81
binutils               Binutils
util-linux             2.12r
mount                  2.12r
module-init-tools      3.3-pre11
e2fsprogs              1.40-WIP
xfsprogs               2.8.18
Linux C Library        > libc.2.5
Dynamic linker (ldd)   2.5
Procps                 3.2.7
Net-tools              1.60
Console-tools          0.2.3
Sh-utils               5.97
udev                   105
Modules Loaded         nfnetlink ip_tables x_tables adm9240 hwmon_vid loop
i2c_ali1535 i2c_ali15x3 i2c_core ide_cd cdrom generic sd_mod alim15x3 sym53c8xx ide_core e100 scsi_transport_spi mii scsi_mod
Problem Description:
jailbird@sky:~$ grep 'kernel unaligned' /proc/cpuinfo                 
kernel unaligned acc    : 34 (pc=fffffc00004bbf58,va=fffffc000394811c)
fffffc00004bbdb0 T __copy_user
fffffc00004bbf50 T csum_ipv6_magic
fffffc00004bc020 T memchr

Quoted 6 lines

Seems to be associated w/ arch/alpha/lib/ev6-csum_ipv6_magic.S
Steps to reproduce:
Use IPv6 on an Alpha EV6 or higher CPU.

I assume that networking passed the arch an unaligned pointer and the arch didn't expect that.

I further assume that this is an alpha shortcoming, and that this behaviour of networking is expected?

Ivan Kokshaysky

2007-06-16 17:03 UTC #2 lore raw

Quoted 10 lines · Andrew Morton

Quoted 10 lines
kernel unaligned acc : 34 (pc=fffffc00004bbf58,va=fffffc000394811c)
fffffc00004bbdb0 T __copy_user
fffffc00004bbf50 T csum_ipv6_magic
fffffc00004bc020 T memchr
Seems to be associated w/ arch/alpha/lib/ev6-csum_ipv6_magic.S
Steps to reproduce:

Quoted 8 lines

Quoted 2 lines
Use IPv6 on an Alpha EV6 or higher CPU.
I assume that networking passed the arch an unaligned pointer and the arch didn't expect that.
I further assume that this is an alpha shortcoming, and that this behaviour of networking is expected?

Indeed, it's alpha bug. The struct in6_addr passed to this routine has 4 byte alignment, so we cannot use normal 64 bit loads.

Hopefully I'll have a fix shortly. BTW, it's not only ev6, ev5 variant is broken as well.

Ivan.