Hi,
On 09/11/08 00:11, Johannes Berg wrote:
On Sat, 2008-11-08 at 23:45 +1100, Shaddy Baddah wrote:
[ 179.249516] zd1211rw 4-3:1.0: zd_usb_rfwrite() value 0x01e6666 bits 24
[ 179.254524] wlan0: Initial auth_alg=0
[ 179.254549] wlan0: authenticate with AP XX:XX:XX:XX:XX:XX
[ 179.256215] Kernel unaligned access at TPC[10129b94]
zd_mac_rx+0x174/0x320 [zd1211rw]
[ 179.349135] Kernel unaligned access at TPC[10129b9c]
zd_mac_rx+0x17c/0x320 [zd1211rw]
[ 179.442852] Kernel unaligned access at TPC[10129ba0]
zd_mac_rx+0x180/0x320 [zd1211rw]
[ 179.536579] Kernel unaligned access at TPC[10129ba4]
zd_mac_rx+0x184/0x320 [zd1211rw]
[ 179.630306] Kernel unaligned access at TPC[10129ba8]
zd_mac_rx+0x188/0x320 [zd1211rw]
I'm keen on troubleshooting this myself. Could you please tell me how I
can get a disassembly intermixed with source. An objdump -S ./zd1211rw.o
is not doing the job. I'd rather not re-compile the whole kernel if
possible, because it takes long. Should I rm the file, do a build, take
the command line and substitute -g for any -O option?
I usually just _add_ -g3 to the command line I get with make V=1 M=...
Johannes, thank you for the tip. It's helped me no end.
So, looking into this problem, I was able to come up with a patch
(attached. Note, it also includes remnants of the patch recommended by
Sebastian Andrzej Siewior in
http://marc.info/?l=linux-wireless&m=122493409906326&w=2). The problem
occurs within compare_ether_addr() and this immediately reminded me that
the patches recommended to me way back last year
(http://marc.info/?l=linux-wireless&m=119543627712471&w=2) also dealt
with this problem.
Looking into how it was solved then, all the compare_ether_addr() calls
were replaced with memcmp() calls. This is what I have done with my
patch as well... but this approach did not fill me with confidence. It
seemed to me like a quick fix that didn't directly address the alignment
problem. And IMO my subsequent findings confirm this.
I now hit the following kernel errors:
> [ 240.139093] Kernel unaligned access at TPC[100f7f44]
> sta_info_get+0x24/0x68 [mac80211]
> [ 240.233255] Kernel unaligned access at TPC[100f7f48]
> sta_info_get+0x28/0x68 [mac80211]
> [ 240.328015] Kernel unaligned access at TPC[100f7f50]
> sta_info_get+0x30/0x68 [mac80211]
> [ 240.422771] Kernel unaligned access at TPC[100f7f44]
> sta_info_get+0x24/0x68 [mac80211]
> [ 240.517554] Kernel unaligned access at TPC[100f7f48]
> sta_info_get+0x28/0x68 [mac80211]
Looking into this, and the underlying problem is again
compare_ether_addr(). Now, I'm sure that replacing this with a memcmp()
is now treading on more toes than just zd1211rw users. And for this
reason, I think a better solution is going to be required.
Does that sound right? I will persist in trying to understand the code
to try and come up with a fix. But obviously, I hope that I can get help
with this to make the former an education exercise, not a kernel
maintenance exercise.
TIA,
Shaddy
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