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* [Bug translator/23666] New: Aggregate operations specified in foreach loop is not respected by the translator
@ 2018-09-15 22:19 agentzh at gmail dot com
  2018-09-16  0:50 ` [Bug translator/23666] " agentzh at gmail dot com
  0 siblings, 1 reply; 2+ messages in thread
From: agentzh at gmail dot com @ 2018-09-15 22:19 UTC (permalink / raw)
  To: systemtap

https://sourceware.org/bugzilla/show_bug.cgi?id=23666

            Bug ID: 23666
           Summary: Aggregate operations specified in foreach loop is not
                    respected by the translator
           Product: systemtap
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: translator
          Assignee: systemtap at sourceware dot org
          Reporter: agentzh at gmail dot com
  Target Milestone: ---

Consider the following example:

```
global a;

probe oneshot {
    a[1] <<< 32;

    a[2] <<< 78;
    a[2] <<< 0;
    a[2] <<< 0;

    a[3] <<< 96;
    a[3] <<< 0;

    foreach ([i] in a @count-) {
        printf("%d: %d\n", i, @sum(a[i]));
    }
}
```

This example generates random output across different runs:

```
$ stap a.stp
1: 32
3: 96
2: 78

$ stap a.stp
2: 78
3: 96
1: 32

$ stap a.stp
3: 96
1: 32
2: 78
```

The MAP operations generated by the stap translator in the kernel source code
misses the COUNT_OP flag in the `_stp_pmap_add_ix()` runtim C function call:

```
      { int rc = _stp_pmap_add_ix (global(s___global_a), ((int64_t)1LL),
((int64_t)32LL), 0, 1, 0, 0, 0); if (unlikely(rc)) { c->last_error = "Array
overflow, check MAXMAPENTRIES"; goto out; }};
```

Using the implicit `-` sorting direction in the stap script example above
instead of `@count-` has the same problem.

Both the kernel and dyninst runtime modes have this issue.

Use of the `@count()` operator inside the `foreach()` loop *body* does make the
problem disappear.

The issue lies in the translator frontend where the use of aggregate operators
in the foreach sorting specification does not affect the stat_op combinations
of the `stat_op` data structure.

-- 
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You are the assignee for the bug.

^ permalink raw reply	[flat|nested] 2+ messages in thread

* [Bug translator/23666] Aggregate operations specified in foreach loop is not respected by the translator
  2018-09-15 22:19 [Bug translator/23666] New: Aggregate operations specified in foreach loop is not respected by the translator agentzh at gmail dot com
@ 2018-09-16  0:50 ` agentzh at gmail dot com
  0 siblings, 0 replies; 2+ messages in thread
From: agentzh at gmail dot com @ 2018-09-16  0:50 UTC (permalink / raw)
  To: systemtap

https://sourceware.org/bugzilla/show_bug.cgi?id=23666

agentzh <agentzh at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |FIXED

--- Comment #1 from agentzh <agentzh at gmail dot com> ---
Just committed a fix to master as commit 92ef5f3da.

-- 
You are receiving this mail because:
You are the assignee for the bug.

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2018-09-15 22:19 [Bug translator/23666] New: Aggregate operations specified in foreach loop is not respected by the translator agentzh at gmail dot com
2018-09-16  0:50 ` [Bug translator/23666] " agentzh at gmail dot com

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