Bug#404834: linux-image-2.6.18-3-sparc64: Kernel unaligned access kills at least sshfs (and may make USB unreliable)
clone 404834 -1
retitle -1 sshfs dies with bus error on sparc
reassign -1 sshfs
thanks
On Thu, Dec 28, 2006 at 02:50:45PM +0100, Sebastian Fontius wrote:
> The mouse works but at boot I get this:
>
> Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]
> Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]
> Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]
> Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]
> Kernel unaligned access at TPC[1000c9e4] ehci_hub_control+0x54c/0x68c [ehci_hcd]
>
> According to http://lkml.org/lkml/2006/9/22/326
>
> >> A 2.6.18-rc kernel compiled with gcc-4.1.1 will throw a few
> >> unaligned accesses when I initialise USB by inserting a USB memory stick.
> >> Removing the memory stick then results in PCI errors and other breakage.
>
> Well, I do not have any USB mass media which is dispensible and as this
> may (or may not) kill data I opted not to try.
>
> A patch is included in http://lkml.org/lkml/2006/9/23/184:
This patch looks ok, I'll push it in.
> $ sshfs smc@phobos:/home/smc phobos/
> Kernel unaligned access at TPC[5d3770] scm_detach_fds_compat+0x74/0x16c
> Kernel unaligned access at TPC[5d37dc] scm_detach_fds_compat+0xe0/0x16c
> Kernel unaligned access at TPC[5d37f8] scm_detach_fds_compat+0xfc/0x16c
> Kernel unaligned access at TPC[5d3810] scm_detach_fds_compat+0x114/0x16c
> Bus-Zugriffsfehler
> $ ls phobos
> ls: phobos: Transport endpoint is not connected
There are two things here: first, the unaligned accesses in kernel.
Those, as Steve pointed out, are harmless, and should not have any
noticeable effect except for slight performance impact (I'll have a
look at them). However, after that sshfs actually dies with bus error,
which is an indication of alignment problems in sshfs itself. I'm
cloning this bug report and reassigning a copy to sshfs. Please
download and install the sshfs package with debugging symbols included
from
http://www.wooyd.org/debian/sshfs
and run it under gdb as follows:
$ gdb sshfs
(gdb) set args smc@phobos:/home/smc phobos/
(gdb) run
After program terminates with bus error, type 'backtrace' at the gdb
prompt and send the output to the sshfs bug report.
Best regards,
--
Jurij Smakov jurij@wooyd.org
Key: http://www.wooyd.org/pgpkey/ KeyID: C99E03CC
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