Bug 4311 - support probing without debuginfo via symbol tables
Summary: support probing without debuginfo via symbol tables
Alias: None
Product: systemtap
Classification: Unclassified
Component: translator (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Jim Keniston
: 4843 (view as bug list)
Depends on:
Reported: 2007-04-02 20:34 UTC by Frank Ch. Eigler
Modified: 2009-03-06 17:20 UTC (History)
3 users (show)

See Also:
Last reconfirmed:


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Description Frank Ch. Eigler 2007-04-02 20:34:37 UTC
There was a report where a module-specific systemtap probe was not able
to be computed (past -p2) without kernel-debuginfo installed, even though
the module debuginfo was there.

We should test whether this is still the case with current code, and fix
it if so.
Comment 1 Frank Ch. Eigler 2007-10-15 19:50:55 UTC
Embracing and extending this bug to cover the desired capability to
do at least rudimentary function probing without debugging information.
This could rely on Module.symvers (for exported symbols only), or some
future mechanism to gather offline symbol data.  /proc/kallsyms or
/boot/Symbols.* is not quite good enough for cross-compilation.
Comment 2 Frank Ch. Eigler 2008-03-20 20:27:25 UTC
*** Bug 4843 has been marked as a duplicate of this bug. ***
Comment 3 Jim Keniston 2008-05-15 17:25:06 UTC
We've divided this feature into three phases:
1. Function boundary tracing using the kernel/module symbol table(s) (from
vmlinux/module elf or from a text file like /proc/kallsyms) 
2. Access to arg values by arg number rather than arg name, plus access to
register values by name.
3. Function boundary tracing of user apps using the apps' symbol tables.

Phase 1 is completed and merged.  As far as I know, it's been explicitly tested
only on i386 and x86_64, but the tests I added to testsuite/{semok,semko} should
run on all architectures.  This feature adds (restores?) the ability to probe
assembly language functions (per Bug 4843).

Phase 2 is completed on i386 and x86_64, and merged.  The functional tests for
the register feature are arch-specific and haven't been checked in yet.

Phase 3 awaits completion of basic dwarf-based probing of user apps.
Comment 4 Ananth Mavinakayanahalli 2009-01-22 08:20:44 UTC
This feature is broken in current upstream systemtap. Needs fixing...
Comment 5 Frank Ch. Eigler 2009-03-06 17:20:17 UTC
bug #6864 covers the restoration of this function