* [Bug runtime/3518] New: unaligned accesses on ia64
@ 2006-11-14 19:10 wcohen at redhat dot com
2006-11-15 19:55 ` [Bug runtime/3518] " hunt at redhat dot com
2006-11-16 1:08 ` wcohen at redhat dot com
0 siblings, 2 replies; 3+ messages in thread
From: wcohen at redhat dot com @ 2006-11-14 19:10 UTC (permalink / raw)
To: systemtap
Josh Stone did some analysis to determine the cause of unaligned accesses on
ia64 machines when the testsuite is being run:
On Thursday, November 09, 2006 11:19 AM, William Cohen wrote:
>> RHLE4 U4 ia64
>> Kernel: Linux 2.6.9-42.0.3.EL #1 SMP Mon Sep 25 17:14:34 EDT 2006
>> ia64 ia64 ia64 GNU/Linux
>> [...]
>> The earliest record of staprun causing unaligned accesses on the ia64
>> machine is Nov 5. See things like the following in the systemtap.log
>> output of dejagnu.
>> [...]
>> staprun(9115): unaligned access to 0x2000000000338014,
ip=0x4000000000007c01
>> staprun(9115): unaligned access to 0x200000000033801c,
ip=0x4000000000007c10
>> staprun(9115): unaligned access to 0x2000000000338024,
ip=0x4000000000007c01
>> staprun(9115): unaligned access to 0x200000000033802c,
ip=0x4000000000007c10
In do_kernel_symbols (runtime/stpd/symbols.c), there are these lines:
144: sym_base = malloc(MAX_SYMBOLS*sizeof(struct
_stp_symbol)+sizeof(int));
[...]
154: *(int *)sym_base = STP_SYMBOLS;
155: syms = (struct _stp_symbol *)(sym_base + sizeof(int));
[...]
178: syms[i].addr = addr;
179: syms[i].symbol = (char *)(dataptr - data);
The ips 7c01 and 7c10 correspond to lines 178 and 179. Line 144 will
return an 8-byte aligned pointer, and then 155 adds 4 to it. From then
on, all access to 8-byte fields through 'syms' will be misaligned.
There's a logging rate limiter that's saving us from seeing more than
four of the same message, thankfully.
One potential solution is to make the transport command a long instead
of int. Such a fix would require changes to the whole transport layer,
though, so I'll leave it to Martin to decide what to do...
Josh
--
Summary: unaligned accesses on ia64
Product: systemtap
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: runtime
AssignedTo: systemtap at sources dot redhat dot com
ReportedBy: wcohen at redhat dot com
http://sourceware.org/bugzilla/show_bug.cgi?id=3518
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* [Bug runtime/3518] unaligned accesses on ia64
2006-11-14 19:10 [Bug runtime/3518] New: unaligned accesses on ia64 wcohen at redhat dot com
@ 2006-11-15 19:55 ` hunt at redhat dot com
2006-11-16 1:08 ` wcohen at redhat dot com
1 sibling, 0 replies; 3+ messages in thread
From: hunt at redhat dot com @ 2006-11-15 19:55 UTC (permalink / raw)
To: systemtap
------- Additional Comments From hunt at redhat dot com 2006-11-15 19:50 -------
I don't have an IA64 for testing. Could someone check the latest from CVS?
I fixed the problem Josh found, but there may be others.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
http://sourceware.org/bugzilla/show_bug.cgi?id=3518
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* [Bug runtime/3518] unaligned accesses on ia64
2006-11-14 19:10 [Bug runtime/3518] New: unaligned accesses on ia64 wcohen at redhat dot com
2006-11-15 19:55 ` [Bug runtime/3518] " hunt at redhat dot com
@ 2006-11-16 1:08 ` wcohen at redhat dot com
1 sibling, 0 replies; 3+ messages in thread
From: wcohen at redhat dot com @ 2006-11-16 1:08 UTC (permalink / raw)
To: systemtap
------- Additional Comments From wcohen at redhat dot com 2006-11-15 20:50 -------
The test results look much better as a result of this patch. -Will
Date: 200611152003
User: wcohen
Kernel: Linux 2.6.9-42.0.3.EL #1 SMP Mon Sep 25 17:14:34 EDT 2006 ia64 ia64 ia64
GNU/Linux
Testsuite summary of failed tests
FAIL: bench (0)
FAIL: probefunc:kernel.statement(0xa00000010006c840) startup (eof)
FAIL: probefunc:kernel.inline("context_switch") compilation
FAIL: buildok/seventeen.stp
FAIL:
/home/wcohen/stap_testing_200611152003/src/testsuite/systemtap.stress/current.stp
startup (timeout)
=== systemtap Summary ===
# of expected passes 240
# of unexpected failures 5
# of unexpected successes 2
# of expected failures 112
# of unknown successes 1
# of known failures 4
# of untested testcases 1
# of unsupported tests 1
runtest completed at Wed Nov 15 15:48:53 2006
--
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
http://sourceware.org/bugzilla/show_bug.cgi?id=3518
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2006-11-14 19:10 [Bug runtime/3518] New: unaligned accesses on ia64 wcohen at redhat dot com
2006-11-15 19:55 ` [Bug runtime/3518] " hunt at redhat dot com
2006-11-16 1:08 ` wcohen at redhat dot com
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