Bug 10091 - Backward compatibility for insn probe point (itrace) on older kernels/utrace
Summary: Backward compatibility for insn probe point (itrace) on older kernels/utrace
Status: RESOLVED FIXED
Alias: None
Product: systemtap
Classification: Unclassified
Component: runtime (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: David Smith
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-04-23 16:29 UTC by Mark Wielaard
Modified: 2009-05-18 18:08 UTC (History)
1 user (show)

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Description Mark Wielaard 2009-04-23 16:29:04 UTC 
Currently insn probe points (itrace) doesn't work on older kernels/utrace. This
results in the following failing tests:

FAIL: itrace1 startup (eof)
FAIL: itrace2 startup (eof)
FAIL: itrace3 startup (eof)

See also http://sourceware.org/ml/systemtap/2009-q2/msg00033.html
Comment 1 David Smith 2009-04-27 20:57:51 UTC 
Fixed in commit 975a582.  Fixed 2 problems:

1) Fixed compile problem.  Older kernels (such as RHEL5) didn't define
arch_has_single_step() and arch_has_block_step()).  Defined them in terms of of
ARCH_HAS_SINGLE_STEP and ARCH_HAS_BLOCK_STEP.

2) Corrected return value of usr_itrace_report_quiesce() for older kernels.
Comment 2 David Smith 2009-05-18 18:08:22 UTC 
More changes in commit cf2742f.

- On ppc, only one insn probe hit was seen between system calls.  See thread
starting at <http://sources.redhat.com/ml/systemtap/2009-q2/msg00033.html> for
more details.

- the testcase was improved to be more thorough and not give fails on platforms
that don't support single or block step.