[DTrace-devel] [oracle/dtrace-utils] 117c90: Fix stack-skip counts for caller and stackdepth

euloh noreply at github.com
Thu Jun 26 03:26:46 UTC 2025 

  Branch: refs/heads/devel
  Home:   https://github.com/oracle/dtrace-utils
  Commit: 117c90ea3f353aa40c84ad9e14343d0b383a3c46
      https://github.com/oracle/dtrace-utils/commit/117c90ea3f353aa40c84ad9e14343d0b383a3c46
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    M bpf/get_bvar.c

  Log Message:
  -----------
  Fix stack-skip counts for caller and stackdepth

Apparently, when we call the BPF get_stack() helper function,
it generally knows how many frames to skip to get the real kernel
stack.  For fentry/fexit, however, this is apparently not the case,
and commit bc65cb44d
("cg: allow providers to specify a skip count for stack retrieval")
added the ability to skip frames for fentry/fexit probes.

When this "skip" is needed, however, it must must be even deeper
when we descend further frames, such as when we call dt_bpf_*()
precompiled functions.

Add this support for dt_bpf_caller() and dt_bpf_stackdepth().
That is, if there are stack-skip frames, skip yet one more frame
when inside a bpf/get_bvar.c function.

Note that we declare the skip count volatile.  The compiler might
optimize code that uses the STACK_SKIP value, but we will subsequently
perform relocations that adjust this value.

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: bcef7e17f4791d16c621da4979366d25bb38e844
      https://github.com/oracle/dtrace-utils/commit/bcef7e17f4791d16c621da4979366d25bb38e844
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    M libdtrace/dt_prov_rawtp.c

  Log Message:
  -----------
  Add stack-skip frame count for rawtp provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: d1feb8af700d036ff176da965204aa2fe0fa020b
      https://github.com/oracle/dtrace-utils/commit/d1feb8af700d036ff176da965204aa2fe0fa020b
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    M test/unittest/sched/tst.stackdepth.d

  Log Message:
  -----------
  test: remove unnecessary "unstable" tag

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 842eabc0ef84ea3876e65894bf43401736320814
      https://github.com/oracle/dtrace-utils/commit/842eabc0ef84ea3876e65894bf43401736320814
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/check_caller_to_stack2.awk
    A test/unittest/variables/bvar/check_stackdepth_to_stack.awk
    A test/unittest/variables/bvar/tst.caller-fbt.d
    A test/unittest/variables/bvar/tst.caller-fbt.r
    A test/unittest/variables/bvar/tst.caller-fbt.r.p
    R test/unittest/variables/bvar/tst.caller2.d
    R test/unittest/variables/bvar/tst.caller2.r
    R test/unittest/variables/bvar/tst.caller2.r.p
    A test/unittest/variables/bvar/tst.stackdepth-fbt.d
    A test/unittest/variables/bvar/tst.stackdepth-fbt.r
    A test/unittest/variables/bvar/tst.stackdepth-fbt.r.p
    R test/unittest/variables/bvar/tst.stackdepth2.d
    R test/unittest/variables/bvar/tst.stackdepth2.r
    R test/unittest/variables/bvar/tst.stackdepth2.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for fbt provider

We will introduce a set of tests for the caller and stackdepth
built-in variables for a wide selection of providers.

For the caller test, we will essentially call
        stack(2);
        sym(caller);
and then compare the caller to the second stack frame using
the new script check_caller_to_stack2.awk.

For the stackdepth test, we will essentially call
        printf("%d\n", stackdepth);
        stack();
and then compare the stackdepth to the reported frames using
the new script check_stackdepth_to_stack.awk.

In this patch, introduce tests for the fbt provider, along with
the support scripts they need.  Subsequent patches will handle
other providers.

The old tst.caller2.d and tst.stackdepth2.d, which tested fbt,
become obsolete.  Remove them.

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 4d44babf4a36c47496c4e77d701a302ef19a8923
      https://github.com/oracle/dtrace-utils/commit/4d44babf4a36c47496c4e77d701a302ef19a8923
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    R test/unittest/builtinvar/tst.caller.d
    A test/unittest/variables/bvar/tst.caller-dtrace.d
    A test/unittest/variables/bvar/tst.caller-dtrace.r
    R test/unittest/variables/bvar/tst.caller.d
    A test/unittest/variables/bvar/tst.stackdepth-dtrace.d
    A test/unittest/variables/bvar/tst.stackdepth-dtrace.r
    R test/unittest/variables/bvar/tst.stackdepth.d

  Log Message:
  -----------
  test: caller and stackdepth tests for dtrace provider

Also, a few old tests, which tested caller and stackdepth using the
dtrace provider, are now superfluous given the new, provider-named
tests.  The old tests were extremely lenient -- e.g., simply
checking that these built-in variables were not -1, even though
both variables are unsigned anyhow!

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 4350d2acee6e7629e20a953e6a59ddf1a7ad52b9
      https://github.com/oracle/dtrace-utils/commit/4350d2acee6e7629e20a953e6a59ddf1a7ad52b9
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/skip_rawtp_old.x
    A test/unittest/variables/bvar/tst.caller-rawtp.d
    A test/unittest/variables/bvar/tst.caller-rawtp.r
    A test/unittest/variables/bvar/tst.caller-rawtp.r.p
    A test/unittest/variables/bvar/tst.caller-rawtp.x
    A test/unittest/variables/bvar/tst.stackdepth-rawtp.d
    A test/unittest/variables/bvar/tst.stackdepth-rawtp.r
    A test/unittest/variables/bvar/tst.stackdepth-rawtp.r.p
    A test/unittest/variables/bvar/tst.stackdepth-rawtp.x

  Log Message:
  -----------
  test: caller and stackdepth tests for rawtp provider

Also, add skip_rawtp_old.x, to skip rawtp testing on older kernels
for the reasons described in the file.

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 0badfcd086f822f0210da0ccdd92b89cafabf528
      https://github.com/oracle/dtrace-utils/commit/0badfcd086f822f0210da0ccdd92b89cafabf528
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-cpc.d
    A test/unittest/variables/bvar/tst.caller-cpc.r
    A test/unittest/variables/bvar/tst.caller-cpc.r.p
    A test/unittest/variables/bvar/tst.stackdepth-cpc.d
    A test/unittest/variables/bvar/tst.stackdepth-cpc.r
    A test/unittest/variables/bvar/tst.stackdepth-cpc.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for cpc provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 8b616886c4e8c9aa549b10efee101f1f3d3ecfd6
      https://github.com/oracle/dtrace-utils/commit/8b616886c4e8c9aa549b10efee101f1f3d3ecfd6
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-ip.d
    A test/unittest/variables/bvar/tst.caller-ip.r
    A test/unittest/variables/bvar/tst.caller-ip.r.p
    A test/unittest/variables/bvar/tst.caller-ip.t
    A test/unittest/variables/bvar/tst.stackdepth-ip.d
    A test/unittest/variables/bvar/tst.stackdepth-ip.r
    A test/unittest/variables/bvar/tst.stackdepth-ip.r.p
    A test/unittest/variables/bvar/tst.stackdepth-ip.t

  Log Message:
  -----------
  test: caller and stackdepth tests for ip provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 0e1ee6ca1b0f7adf53c230e3947e1701c20cdb50
      https://github.com/oracle/dtrace-utils/commit/0e1ee6ca1b0f7adf53c230e3947e1701c20cdb50
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    R test/unittest/builtinvar/tst.caller1.d
    A test/unittest/variables/bvar/tst.caller-profile.d
    A test/unittest/variables/bvar/tst.caller-profile.r
    A test/unittest/variables/bvar/tst.caller-profile.r.p
    A test/unittest/variables/bvar/tst.stackdepth-profile.d
    A test/unittest/variables/bvar/tst.stackdepth-profile.r
    A test/unittest/variables/bvar/tst.stackdepth-profile.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for profile provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 0a15fd0e636ca8bc2645ba8d3af64cb3751be919
      https://github.com/oracle/dtrace-utils/commit/0a15fd0e636ca8bc2645ba8d3af64cb3751be919
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-sched.d
    A test/unittest/variables/bvar/tst.caller-sched.r
    A test/unittest/variables/bvar/tst.caller-sched.r.p
    A test/unittest/variables/bvar/tst.stackdepth-sched.d
    A test/unittest/variables/bvar/tst.stackdepth-sched.r
    A test/unittest/variables/bvar/tst.stackdepth-sched.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for sched provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 4b29eafb866288cf57885b62447ce32cf3d1ad6e
      https://github.com/oracle/dtrace-utils/commit/4b29eafb866288cf57885b62447ce32cf3d1ad6e
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-proc.d
    A test/unittest/variables/bvar/tst.caller-proc.r
    A test/unittest/variables/bvar/tst.caller-proc.r.p
    A test/unittest/variables/bvar/tst.stackdepth-proc.d
    A test/unittest/variables/bvar/tst.stackdepth-proc.r
    A test/unittest/variables/bvar/tst.stackdepth-proc.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for proc provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: f2a056c905b0e5d2aadf73372ae16c5e1347a822
      https://github.com/oracle/dtrace-utils/commit/f2a056c905b0e5d2aadf73372ae16c5e1347a822
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-rawfbt.d
    A test/unittest/variables/bvar/tst.caller-rawfbt.r
    A test/unittest/variables/bvar/tst.caller-rawfbt.r.p
    A test/unittest/variables/bvar/tst.stackdepth-rawfbt.d
    A test/unittest/variables/bvar/tst.stackdepth-rawfbt.r
    A test/unittest/variables/bvar/tst.stackdepth-rawfbt.r.p

  Log Message:
  -----------
  test: caller and stackdepth tests for rawfbt provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: b6294ac56cb85981531e16d43739747ea913eac1
      https://github.com/oracle/dtrace-utils/commit/b6294ac56cb85981531e16d43739747ea913eac1
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/tst.caller-io.r
    A test/unittest/variables/bvar/tst.caller-io.r.p
    A test/unittest/variables/bvar/tst.caller-io.sh
    A test/unittest/variables/bvar/tst.caller-io.x
    A test/unittest/variables/bvar/tst.stackdepth-io.r
    A test/unittest/variables/bvar/tst.stackdepth-io.r.p
    A test/unittest/variables/bvar/tst.stackdepth-io.sh
    A test/unittest/variables/bvar/tst.stackdepth-io.x

  Log Message:
  -----------
  test: caller and stackdepth tests for io provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


  Commit: 162b818df69c3608cbc1757fdf30d29927306c36
      https://github.com/oracle/dtrace-utils/commit/162b818df69c3608cbc1757fdf30d29927306c36
  Author: Eugene Loh <eugene.loh at oracle.com>
  Date:   2025-06-25 (Wed, 25 Jun 2025)

  Changed paths:
    A test/unittest/variables/bvar/skip_lockstat_5.10.x
    A test/unittest/variables/bvar/tst.caller-lockstat.d
    A test/unittest/variables/bvar/tst.caller-lockstat.r
    A test/unittest/variables/bvar/tst.caller-lockstat.r.p
    A test/unittest/variables/bvar/tst.caller-lockstat.t
    A test/unittest/variables/bvar/tst.caller-lockstat.x
    A test/unittest/variables/bvar/tst.stackdepth-lockstat.d
    A test/unittest/variables/bvar/tst.stackdepth-lockstat.r
    A test/unittest/variables/bvar/tst.stackdepth-lockstat.r.p
    A test/unittest/variables/bvar/tst.stackdepth-lockstat.t
    A test/unittest/variables/bvar/tst.stackdepth-lockstat.x

  Log Message:
  -----------
  test: caller and stackdepth tests for lockstat provider

Signed-off-by: Eugene Loh <eugene.loh at oracle.com>
Reviewed-by: Nick Alcock <nick.alcock at oracle.com>


Compare: https://github.com/oracle/dtrace-utils/compare/f0e1424fa41b...162b818df69c

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