[Bug gdb/16101] New: gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[Bug gdb/16101] New: gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[macro@linux-mips.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=16101

            Bug ID: 16101
           Summary: gdb.base/dprintf.exp agent-printf failures with
                    non-Z0-supporting gdbservers
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: macro@linux-mips.org
            Target: arm-linux-gnueabi, mips-linux-gnu, powerpc-linux-gnu

There is an issue with agent dprintf on targets where `gdbserver' does
not support the `Z0' packet.  There GDB inserts software breakpoints
itself, by poking at memory explicitly to modify the instruction stream.
This includes dprintf breakpoints.  Once such a breakpoint has hit
`gdbserver' reports the hit to GDB (without executing the dprintf
request).  GDB in turn sees `agent-printf' in the list of breakpoint
commands and complains:

May only run agent-printf on the target

This is observed in GDB testing:

FAIL: gdb.base/dprintf.exp: 1st dprintf, agent
FAIL: gdb.base/dprintf.exp: 2nd dprintf, agent

on at least the arm-linux-gnueabi, mips-linux-gnu and powerpc-linux-gnu
targets.

I think it would be consistent if agent dprintf was not allowed for GDB
breakpoints.  However disabling the breakpoint commands feature on such
targets altogether would regress hardware (`Z1') breakpoints where
supported, so it looks to me that agent dprintf should be a
per-breakpoint feature, resorting to one of the other styles (probably
gdb) for GDB breakpoints.

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[Bug gdb/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[palves at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16101

Pedro Alves <palves at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |palves at redhat dot com

--- Comment #1 from Pedro Alves <palves at redhat dot com> ---
See:

 https://sourceware.org/ml/gdb-patches/2013-10/msg00615.html

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[Bug gdb/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[teawater at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16101

teawater <teawater at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |teawater at gmail dot com
           Assignee|unassigned at sourceware dot org   |teawater at gmail dot com

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[Bug gdb/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[cvs-commit at gcc dot gnu.org]

http://sourceware.org/bugzilla/show_bug.cgi?id=16101

--- Comment #2 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "gdb and binutils".

The branch, master has been updated
       via  0000e5ccd8615d632ac6ddc831cd5d3af8084737 (commit)
      from  c66a241cde1b8fe4207d425c9956cb6dac948732 (commit)

Those revisions listed above that are new to this repository have
not appeared on any other notification email; so we list those
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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=0000e5ccd8615d632ac6ddc831cd5d3af8084737

commit 0000e5ccd8615d632ac6ddc831cd5d3af8084737
Author: Pedro Alves <palves@redhat.com>
Date:   Thu Jan 9 18:33:45 2014 +0000

    Handle the case of a remote target supporting target side commands, but not
on software breakpoints.

    Although we can tell upfront whether a remote target supports target
    side commands, we can only tell whether the target supports that in
    combination with a given breakpoint kind (software, hardware,
    watchpoints, etc.) when we go and try to insert such a breakpoint kind
    the first time.  It's not desirable to make remote_insert_breakpoint
    simply return -1 in this case, because if the breakpoint was set in a
    shared library, insert_bp_location will assume that the breakpoint
    insertion failed because the library wasn't mapped in.

    insert_bp_location already handles errors/exceptions thrown from the
    target_insert_xxx methods, exactly so the backend can tell the user
    the detailed reason the insertion of hw breakpoints failed.  But, in
    the case of software breakpoints, it discards the detailed error
    message.

    So the patch makes insert_bp_location use the error's message for SW
    breakpoints too, and, introduces a NOT_SUPPORTED_ERROR error code so
    that insert_bp_location doesn't confuse the error for failure due to a
    shared library disappearing.

    The result is:

    (gdb) c
    Warning:
    Cannot insert breakpoint 2: Target doesn't support breakpoints that have
target side commands.

    2014-01-09  Pedro Alves  <palves@redhat.com>
            Hui Zhu  <hui@codesourcery.com>

        PR gdb/16101
        * breakpoint.c (insert_bp_location): Rename hw_bp_err_string to
        bp_err_string.  Don't mark the location shlib_disabled if the
        error thrown wasn't a generic or memory error.  Catch errors
        thrown while inserting breakpoints in overlayed code.  Output
        error message of software breakpoints.
        * remote.c (remote_insert_breakpoint): If this breakpoint has
        target-side commands but this stub doesn't support Z0 packets,
        throw NOT_SUPPORTED_ERROR error.
        * exceptions.h (enum errors) <NOT_SUPPORTED_ERROR>: New error.
        * target.h (target_insert_breakpoint): Extend comment.
        (target_insert_hw_breakpoint): Add comment.

-----------------------------------------------------------------------

Summary of changes:
 gdb/ChangeLog    |   16 ++++++++
 gdb/breakpoint.c |  105 +++++++++++++++++++++++++++++++++++++++--------------
 gdb/exceptions.h |    3 ++
 gdb/remote.c     |    6 +++
 gdb/target.h     |   11 +++++-
 5 files changed, 111 insertions(+), 30 deletions(-)

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[Bug breakpoints/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[teawater at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16101

teawater <teawater at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|gdb                         |breakpoints

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[Bug breakpoints/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16101

--- Comment #3 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "gdb and binutils".

The branch, master has been updated
       via  88bbeca9d5e9429dbd2a11d754f24d649b8e5488 (commit)
      from  d23487918b315cccd04c2b60a7cf7775920caecb (commit)

Those revisions listed above that are new to this repository have
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https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=88bbeca9d5e9429dbd2a11d754f24d649b8e5488

commit 88bbeca9d5e9429dbd2a11d754f24d649b8e5488
Author: Hui Zhu <hui@codesourcery.com>
Date:   Mon Mar 24 19:30:50 2014 +0000

    Fix PR breakpoints/16101: gdb.base/dprintf.exp agent-printf failures with
non-Z0-supporting gdbservers

    After a previous patch that was committed by Pedro (0000e5cc), trying
    to set a dprintf with with a GDBserver that doesn't support agent
    commands at all now throws an error.  But the dprintf tests still fail
    with some GDBserver targets because they doesn't try to handle the
    case of the server reporting support for breakpoint commands, but not
    be able to use those in combination with Z0 (because Z0 isn't actually
    supported, for example):

     FAIL: gdb.base/dprintf.exp: 1st dprintf, agent
     FAIL: gdb.base/dprintf.exp: 2nd dprintf, agent
     FAIL: gdb.base/dprintf.exp: dprintf info 2 (pattern 4)

    Similarly for the MI test.

    This patch makes the tests handle this scenario.

    Tested with native, and native gdbserver on x86_64 Fedora 17.

    Also tested with the native-gdbserver.exp board hacked with:

     set GDBFLAGS "${GDBFLAGS} -ex \"set remote breakpoint-commands off\""

    (actually, "set remote breakpoint-commands off" is presently broken,
    so this was on top of a fix for that command.)

    which results in:
     (gdb) PASS: gdb.base/dprintf.exp: 2nd dprintf, gdb
     set dprintf-style agent
     warning: Target cannot run dprintf commands, falling back to GDB printf
     warning: Target cannot run dprintf commands, falling back to GDB printf
     (gdb) UNSUPPORTED: gdb.base/dprintf.exp: set dprintf style to agent

    gdb.sum:
     Running target native-gdbserver
     Running ../../../src/gdb/testsuite/gdb.base/dprintf.exp ...
     PASS: gdb.base/dprintf.exp: dprintf
     PASS: gdb.base/dprintf.exp: dprintf foo
     PASS: gdb.base/dprintf.exp: dprintf 29
     PASS: gdb.base/dprintf.exp: dprintf foo,"At foo entry\n"
     PASS: gdb.base/dprintf.exp: ignore $bpnum 1
     PASS: gdb.base/dprintf.exp: dprintf 26,"arg=%d, g=%d\n", arg, g
     PASS: gdb.base/dprintf.exp: dprintf info 1
     PASS: gdb.base/dprintf.exp: break 27
     PASS: gdb.base/dprintf.exp: 1st dprintf, gdb
     PASS: gdb.base/dprintf.exp: 2nd dprintf, gdb
     UNSUPPORTED: gdb.base/dprintf.exp: set dprintf style to agent
     PASS: gdb.base/dprintf.exp: Set dprintf style to an unrecognized type

    And also with the native-gdbserver.exp board hacked with:

     set GDBFLAGS "${GDBFLAGS} -ex \"set remote Z-packet off\""

    which results in:
     (gdb) continue
     Continuing.
     Warning:
     Cannot insert breakpoint 3: Target doesn't support breakpoints that have
target side commands.
     Cannot insert breakpoint 4: Target doesn't support breakpoints that have
target side commands.

     (gdb) UNSUPPORTED: gdb.base/dprintf.exp: 1st dprintf, agent

    gdb.sum:
     Running target native-gdbserver
     Running ../../../src/gdb/testsuite/gdb.base/dprintf.exp ...
     PASS: gdb.base/dprintf.exp: dprintf
     PASS: gdb.base/dprintf.exp: dprintf foo
     PASS: gdb.base/dprintf.exp: dprintf 29
     PASS: gdb.base/dprintf.exp: dprintf foo,"At foo entry\n"
     PASS: gdb.base/dprintf.exp: ignore $bpnum 1
     PASS: gdb.base/dprintf.exp: dprintf 26,"arg=%d, g=%d\n", arg, g
     PASS: gdb.base/dprintf.exp: dprintf info 1
     PASS: gdb.base/dprintf.exp: break 27
     PASS: gdb.base/dprintf.exp: 1st dprintf, gdb
     PASS: gdb.base/dprintf.exp: 2nd dprintf, gdb
     PASS: gdb.base/dprintf.exp: set dprintf style to agent
     UNSUPPORTED: gdb.base/dprintf.exp: 1st dprintf, agent
     PASS: gdb.base/dprintf.exp: Set dprintf style to an unrecognized type

    (One of the new comments mentions breakpoint always-inserted mode.
    Actually testing with breakpoint always-inserted mode fails these
    dprintf tests, due to the way they are written.  But that'll take a
    more substancial rewrite of the tests, so I'm leaving that for another
    day.)

    gdb/testsuite/
    2014-03-24  Hui Zhu  <hui@codesourcery.com>
            Pedro Alves  <palves@redhat.com>

        PR breakpoints/16101
        * gdb.base/dprintf.exp: Use unsupported rather than changing the
        test pass/fail messages.  Detect missing support for dprintf when
        breakpoints are actually inserted.
        * gdb.base/mi-dprintf.exp: Detect missing support for dprintf when
        breakpoints are actually inserted.
        * lib/mi-support.exp (mi_run_cmd_full): Return -1 if continue
        fails.

-----------------------------------------------------------------------

Summary of changes:
 gdb/testsuite/ChangeLog             |   12 ++++++++
 gdb/testsuite/gdb.base/dprintf.exp  |   53 ++++++++++++++++++++++++----------
 gdb/testsuite/gdb.mi/mi-dprintf.exp |   45 ++++++++++++++++++------------
 gdb/testsuite/lib/mi-support.exp    |    1 +
 4 files changed, 77 insertions(+), 34 deletions(-)

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[Bug breakpoints/16101] gdb.base/dprintf.exp agent-printf failures with non-Z0-supporting gdbservers

[palves at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16101

Pedro Alves <palves at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |7.8

--- Comment #4 from Pedro Alves <palves at redhat dot com> ---
Fixed.

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