[patch] Fix warning: Invalid entry in .debug_gdb_scripts section

[patch] Fix warning: Invalid entry in .debug_gdb_scripts section

[Jan Kratochvil]

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Hi,

https://bugzilla.redhat.com/show_bug.cgi?id=1429598

there remains questionable whether bfd_get_section_by_name() should not return
an error for !SEC_LOAD but I haven't investigated that.

Also it could have a testcase.

OK for check-in?


Jan

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gdb/ChangeLog
2017-03-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* auto-load.c (auto_load_section_scripts): Check also SEC_LOAD.

diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 56914c8..63b54b8 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1174,7 +1174,8 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
   bfd_byte *data = NULL;
 
   scripts_sect = bfd_get_section_by_name (abfd, section_name);
-  if (scripts_sect == NULL)
+  if (scripts_sect == NULL
+      || (bfd_get_section_flags (abfd, scripts_sect) & SEC_LOAD) == 0)
     return;
 
   if (!bfd_get_full_section_contents (abfd, scripts_sect, &data))

Re: [patch] Fix warning: Invalid entry in .debug_gdb_scripts section

[Pedro Alves]

On 03/16/2017 03:41 PM, Jan Kratochvil wrote:
> Hi,
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1429598
> 
> there remains questionable whether bfd_get_section_by_name() should not return
> an error for !SEC_LOAD but I haven't investigated that.
> 
> Also it could have a testcase.
> 
> OK for check-in?

I don't think you've supplied enough rationale.

Why is this the right thing to do?

Shouldn't we be able to load scripts from debug-only sections?

A testcase would indeed be good to have.

Thanks,
Pedro Alves

Re: [patch] Fix warning: Invalid entry in .debug_gdb_scripts section

[Jan Kratochvil]

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On Thu, 16 Mar 2017 18:03:41 +0100, Pedro Alves wrote:
> I don't think you've supplied enough rationale.

I forgot to copy-paste prepared:

/usr/bin/rustc
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [15] .debug_gdb_scripts PROGBITS        00000000000008ed 0008ed 000022 00 AMS  0   0  1

/usr/lib/debug/usr/bin/rustc.debug
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [15] .debug_gdb_scripts NOBITS          00000000000008ed 000280 000022 00 AMS  0   0  1


> Shouldn't we be able to load scripts from debug-only sections?

I agree there is better to use SEC_HAS_CONTENTS, right?


> A testcase would indeed be good to have.

OK, I will update the patch later.


Jan

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gdb/ChangeLog
2017-03-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* auto-load.c (auto_load_section_scripts): Check SEC_HAS_CONTENTS.

diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 56914c8..edaf264 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1174,7 +1174,8 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
   bfd_byte *data = NULL;
 
   scripts_sect = bfd_get_section_by_name (abfd, section_name);
-  if (scripts_sect == NULL)
+  if (scripts_sect == NULL
+      || (bfd_get_section_flags (abfd, scripts_sect) & SEC_HAS_CONTENTS) == 0)
     return;
 
   if (!bfd_get_full_section_contents (abfd, scripts_sect, &data))

Re: [patch] Fix warning: Invalid entry in .debug_gdb_scripts section

[Pedro Alves]

On 03/16/2017 05:39 PM, Jan Kratochvil wrote:
> On Thu, 16 Mar 2017 18:03:41 +0100, Pedro Alves wrote:
>> I don't think you've supplied enough rationale.
> 
> I forgot to copy-paste prepared:
> 
> /usr/bin/rustc
> Section Headers:
>   [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
>   [15] .debug_gdb_scripts PROGBITS        00000000000008ed 0008ed 000022 00 AMS  0   0  1
> 
> /usr/lib/debug/usr/bin/rustc.debug
> Section Headers:
>   [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
>   [15] .debug_gdb_scripts NOBITS          00000000000008ed 000280 000022 00 AMS  0   0  1
> 

Well, that's just a tool output, not a self-contained
rationale/explanation.  With only that, any reviewer will have to
guess things that you probably have already discovered while
debugging the issue.  Josh said that the script is still loaded
fine.  I guess that's because GDB actually tries to read the script
twice, once from rustc, which succeeds, and another time from
rustc.debug, which runs into a zero'ed script ID type, which is
invalid exactly to catch this type of problems.

>> Shouldn't we be able to load scripts from debug-only sections?
> 
> I agree there is better to use SEC_HAS_CONTENTS, right?

Yes, I think so.

Thanks,
Pedro Alves

[patchv3] Fix warning: Invalid entry in .debug_gdb_scripts section

[Jan Kratochvil]

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On Thu, 16 Mar 2017 18:39:13 +0100, Jan Kratochvil wrote:
> OK, I will update the patch later.

Included.

OK for check-in?


Jan

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gdb/ChangeLog
2017-03-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* auto-load.c (auto_load_section_scripts): Check SEC_HAS_CONTENTS.

gdb/testsuite/ChangeLog
2017-03-19  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.python/py-section-script.exp (sepdebug): New testcases.

diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 56914c8..edaf264 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1174,7 +1174,8 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
   bfd_byte *data = NULL;
 
   scripts_sect = bfd_get_section_by_name (abfd, section_name);
-  if (scripts_sect == NULL)
+  if (scripts_sect == NULL
+      || (bfd_get_section_flags (abfd, scripts_sect) & SEC_HAS_CONTENTS) == 0)
     return;
 
   if (!bfd_get_full_section_contents (abfd, scripts_sect, &data))
diff --git a/gdb/testsuite/gdb.python/py-section-script.exp b/gdb/testsuite/gdb.python/py-section-script.exp
index 52e1e3e..cf6b631 100644
--- a/gdb/testsuite/gdb.python/py-section-script.exp
+++ b/gdb/testsuite/gdb.python/py-section-script.exp
@@ -114,3 +114,38 @@ gdb_test "continue" ".*Breakpoint.*"
 gdb_test "print ss" " = a=<1> b=<2>"
 
 gdb_test "test-cmd 1 2 3" "test-cmd output, arg = 1 2 3"
+
+
+with_test_prefix "sepdebug" {
+    gdb_exit
+
+    set result [catch "exec eu-strip -g -f ${binfile}.debug ${binfile}" output]
+    verbose "result is $result"
+    verbose "output is $output"
+    if {$result != 0 || $output != ""} {
+	unsupported "cannot produce separate debug info files"
+	return
+    }
+
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+
+    gdb_test_no_output "set auto-load safe-path ${remote_python_file}:${binfile}" \
+	"set auto-load safe-path"
+    set test "load sepdebug"
+    gdb_test_multiple "file $binfile" $test {
+	-re "\r\nwarning: Invalid entry in \\.debug_gdb_scripts section.*\r\n$gdb_prompt $" {
+	    fail $test
+	}
+	-re "done\\.\r\n$gdb_prompt $" {
+	    pass $test
+	}
+    }
+
+    # Again, with a regexp this time.
+    gdb_test "info auto-load python-scripts ${testfile}" "Yes.*${testfile}.py.*"
+
+    # Again, with a regexp that matches no scripts.
+    gdb_test "info auto-load python-scripts no-script-matches-this" \
+      "No auto-load scripts matching no-script-matches-this."
+}

Re: [patchv3] Fix warning: Invalid entry in .debug_gdb_scripts section

[Pedro Alves]

On 03/19/2017 10:38 PM, Jan Kratochvil wrote:
> On Thu, 16 Mar 2017 18:39:13 +0100, Jan Kratochvil wrote:
>> > OK, I will update the patch later.
> Included.
> 
> OK for check-in?

Thanks.

> gdb/ChangeLog
> 2017-03-16  Jan Kratochvil  <jan.kratochvil@redhat.com>
> 
> 	* auto-load.c (auto_load_section_scripts): Check SEC_HAS_CONTENTS.
> 
> gdb/testsuite/ChangeLog
> 2017-03-19  Jan Kratochvil  <jan.kratochvil@redhat.com>
> 
> 	* gdb.python/py-section-script.exp (sepdebug): New testcases.
> 


> diff --git a/gdb/testsuite/gdb.python/py-section-script.exp b/gdb/testsuite/gdb.python/py-section-script.exp
> index 52e1e3e..cf6b631 100644
> --- a/gdb/testsuite/gdb.python/py-section-script.exp
> +++ b/gdb/testsuite/gdb.python/py-section-script.exp
> @@ -114,3 +114,38 @@ gdb_test "continue" ".*Breakpoint.*"
>  gdb_test "print ss" " = a=<1> b=<2>"
>  
>  gdb_test "test-cmd 1 2 3" "test-cmd output, arg = 1 2 3"
> +
> +
> +with_test_prefix "sepdebug" {

Please add a leading comment here, helping folks reading this understand
what the test is about.  Something like "eu-strip creates NOBITS
.debug_gdb_scripts sections in the debug files.  Make sure those are
ignored silently."

OK with that change.

Thanks,
Pedro Alves

> +    gdb_exit
> +
> +    set result [catch "exec eu-strip -g -f ${binfile}.debug ${binfile}" output]
> +    verbose "result is $result"
> +    verbose "output is $output"
> +    if {$result != 0 || $output != ""} {
> +	unsupported "cannot produce separate debug info files"
> +	return
> +    }
> +
> +    gdb_start
> +    gdb_reinitialize_dir $srcdir/$subdir
> +
> +    gdb_test_no_output "set auto-load safe-path ${remote_python_file}:${binfile}" \
> +	"set auto-load safe-path"
> +    set test "load sepdebug"
> +    gdb_test_multiple "file $binfile" $test {
> +	-re "\r\nwarning: Invalid entry in \\.debug_gdb_scripts section.*\r\n$gdb_prompt $" {
> +	    fail $test
> +	}
> +	-re "done\\.\r\n$gdb_prompt $" {
> +	    pass $test
> +	}
> +    }
> +
> +    # Again, with a regexp this time.
> +    gdb_test "info auto-load python-scripts ${testfile}" "Yes.*${testfile}.py.*"
> +
> +    # Again, with a regexp that matches no scripts.
> +    gdb_test "info auto-load python-scripts no-script-matches-this" \
> +      "No auto-load scripts matching no-script-matches-this."
> +}
> 

[commit] [patchv3] Fix warning: Invalid entry in .debug_gdb_scripts section

[Jan Kratochvil]

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On Wed, 29 Mar 2017 16:11:41 +0200, Pedro Alves wrote:
> OK with that change.

Checked in.


Thanks,
Jan

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From: Jan Kratochvil <jan.kratochvil@redhat.com>
Subject: [PATCH] Fix warning: Invalid entry in .debug_gdb_scripts section
Date: Wed, 29 Mar 2017 21:53:43 +0200

$ gdb rustc
Reading symbols from rustc...Reading symbols from /usr/lib/debug/usr/bin/rustc.debug...done.
done.
warning: Invalid entry in .debug_gdb_scripts section

/usr/bin/rustc
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [15] .debug_gdb_scripts PROGBITS        00000000000008ed 0008ed 000022 00 AMS  0   0  1

/usr/lib/debug/usr/bin/rustc.debug
Section Headers:
  [Nr] Name              Type            Address          Off    Size   ES Flg Lk Inf Al
  [15] .debug_gdb_scripts NOBITS          00000000000008ed 000280 000022 00 AMS  0   0  1

There remains questionable whether bfd_get_section_by_name() should not return
an error for !SEC_LOAD but I haven't investigated that.

gdb/ChangeLog
2017-03-29  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* auto-load.c (auto_load_section_scripts): Check SEC_HAS_CONTENTS.

gdb/testsuite/ChangeLog
2017-03-29  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.python/py-section-script.exp (sepdebug): New testcases.
---
 gdb/ChangeLog                                  |  4 +++
 gdb/auto-load.c                                |  3 +-
 gdb/testsuite/ChangeLog                        |  4 +++
 gdb/testsuite/gdb.python/py-section-script.exp | 38 ++++++++++++++++++++++++++
 4 files changed, 48 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 23df636..bfa5358 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2017-03-29  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* auto-load.c (auto_load_section_scripts): Check SEC_HAS_CONTENTS.
+
 2017-03-29  Yao Qi  <yao.qi@linaro.org>
 
 	* gdbthread.h (struct thread_info): Declare constructor and
diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 56914c8..edaf264 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -1174,7 +1174,8 @@ auto_load_section_scripts (struct objfile *objfile, const char *section_name)
   bfd_byte *data = NULL;
 
   scripts_sect = bfd_get_section_by_name (abfd, section_name);
-  if (scripts_sect == NULL)
+  if (scripts_sect == NULL
+      || (bfd_get_section_flags (abfd, scripts_sect) & SEC_HAS_CONTENTS) == 0)
     return;
 
   if (!bfd_get_full_section_contents (abfd, scripts_sect, &data))
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 5241a27..eb543eb 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2017-03-29  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* gdb.python/py-section-script.exp (sepdebug): New testcases.
+
 2017-03-28  Anton Kolesov  <anton.kolesov@synopsys.com>
 
 	* gdb.arch/arc-analyze-prologue.S: New file.
diff --git a/gdb/testsuite/gdb.python/py-section-script.exp b/gdb/testsuite/gdb.python/py-section-script.exp
index 52e1e3e..6707156 100644
--- a/gdb/testsuite/gdb.python/py-section-script.exp
+++ b/gdb/testsuite/gdb.python/py-section-script.exp
@@ -114,3 +114,41 @@ gdb_test "continue" ".*Breakpoint.*"
 gdb_test "print ss" " = a=<1> b=<2>"
 
 gdb_test "test-cmd 1 2 3" "test-cmd output, arg = 1 2 3"
+
+
+# eu-strip creates NOBITS .debug_gdb_scripts sections in the debug files.
+# Make sure those are ignored silently.
+
+with_test_prefix "sepdebug" {
+    gdb_exit
+
+    set result [catch "exec eu-strip -g -f ${binfile}.debug ${binfile}" output]
+    verbose "result is $result"
+    verbose "output is $output"
+    if {$result != 0 || $output != ""} {
+	unsupported "cannot produce separate debug info files"
+	return
+    }
+
+    gdb_start
+    gdb_reinitialize_dir $srcdir/$subdir
+
+    gdb_test_no_output "set auto-load safe-path ${remote_python_file}:${binfile}" \
+	"set auto-load safe-path"
+    set test "load sepdebug"
+    gdb_test_multiple "file $binfile" $test {
+	-re "\r\nwarning: Invalid entry in \\.debug_gdb_scripts section.*\r\n$gdb_prompt $" {
+	    fail $test
+	}
+	-re "done\\.\r\n$gdb_prompt $" {
+	    pass $test
+	}
+    }
+
+    # Again, with a regexp this time.
+    gdb_test "info auto-load python-scripts ${testfile}" "Yes.*${testfile}.py.*"
+
+    # Again, with a regexp that matches no scripts.
+    gdb_test "info auto-load python-scripts no-script-matches-this" \
+      "No auto-load scripts matching no-script-matches-this."
+}
-- 
2.9.3