[PATCH v4 0/4] gdb: add gdb_attach to fix failed testcases

[PATCH v4 0/4] gdb: add gdb_attach to fix failed testcases

[Tiezhu Yang]

Hi,

Please review this v4 patchset, thank you.

The following suggestion is very good, it needs us to do more work.
I think we can do it later after this patchset is merged into master.

https://sourceware.org/pipermail/gdb-patches/2022-March/186795.html

Tiezhu Yang (4):
  gdb: testsuite: remove attach test from can_spawn_for_attach
  gdb: testsuite: add new gdb_attach to check "attach" command
  gdb: testsuite: use gdb_attach to fix attach-pie-noexec.exp
  gdb: testsuite: use gdb_attach to fix jit-elf.exp

 gdb/testsuite/gdb.base/attach-pie-noexec.exp |  5 +-
 gdb/testsuite/gdb.base/jit-elf.exp           | 24 ++++++----
 gdb/testsuite/lib/gdb.exp                    | 70 ++++++++++++----------------
 3 files changed, 50 insertions(+), 49 deletions(-)

-- 
2.1.0

[PATCH v4 1/4] gdb: testsuite: remove attach test from can_spawn_for_attach

[Tiezhu Yang]

As Pedro Alves said, caching procs should not issue pass/fail [1],
this commit removes attach test from can_spawn_for_attach, at the
same time, use "verbose -log" instead of "unsupported" to get a
trace about why a test run doesn't support spawning for attach.

[1] https://sourceware.org/pipermail/gdb-patches/2022-March/186311.html

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 gdb/testsuite/lib/gdb.exp | 52 ++++++++---------------------------------------
 1 file changed, 9 insertions(+), 43 deletions(-)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 08726f7..89dcd0a 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5090,12 +5090,12 @@ proc gdb_exit { } {
 # Return true if we can spawn a program on the target and attach to
 # it.
 
-gdb_caching_proc can_spawn_for_attach {
+proc can_spawn_for_attach { } {
     # We use exp_pid to get the inferior's pid, assuming that gives
     # back the pid of the program.  On remote boards, that would give
     # us instead the PID of e.g., the ssh client, etc.
     if [is_remote target] then {
-	unsupported "skip attach tests (target is remote)"
+	verbose -log "can't spawn for attach (target is remote)"
 	return 0
     }
 
@@ -5103,50 +5103,10 @@ gdb_caching_proc can_spawn_for_attach {
     # stub-like, where GDB finds the program already started on
     # initial connection.
     if {[target_info exists use_gdb_stub]} {
-	unsupported "skip attach tests (target is stub)"
+	verbose -log "can't spawn for attach (target is stub)"
 	return 0
     }
 
-    set me "can_spawn_for_attach"
-    set src { int main (void) { sleep (600); return 0; } }
-    if {![gdb_simple_compile $me $src executable]} {
-        return 0
-    }
-
-    set test_spawn_id [spawn_wait_for_attach $obj]
-    set test_pid [spawn_id_get_pid $test_spawn_id]
-
-    gdb_start
-    file delete $obj
-    gdb_test_multiple "attach $test_pid" "can spawn for attach" {
-        -re -wrap "Attaching to process $test_pid\r\n.*No executable file now.*" {
-          pass $gdb_test_name
-          kill_wait_spawned_process $test_spawn_id
-          return 1
-        }
-        -re -wrap "Attaching to process $test_pid\r\n.*ptrace: Operation not permitted\\." {
-          unsupported "$gdb_test_name (Operation not permitted)"
-          kill_wait_spawned_process $test_spawn_id
-          return 0
-        }
-        -re -wrap "Attaching to process $test_pid\r\n.*Attaching to process $test_pid failed" {
-          unsupported "$gdb_test_name (Attaching to process failed)"
-          kill_wait_spawned_process $test_spawn_id
-          return 0
-        }
-        -re -wrap "Attaching to process $test_pid\r\n.*XML support was disabled at compile time.*" {
-          pass $gdb_test_name
-          kill_wait_spawned_process $test_spawn_id
-          return 1
-        }
-        -re "A program is being debugged already.  Kill it. .y or n. " {
-          send_gdb "y\n"
-          exp_continue
-        }
-    }
-
-    kill_wait_spawned_process $test_spawn_id
-
     # Assume yes.
     return 1
 }
@@ -5196,6 +5156,12 @@ proc spawn_id_get_pid { spawn_id } {
 proc spawn_wait_for_attach { executable_list } {
     set spawn_id_list {}
 
+    if ![can_spawn_for_attach] {
+	# The caller should have checked can_spawn_for_attach itself
+	# before getting here.
+	error "can't spawn for attach with this target/board"
+    }
+
     foreach {executable} $executable_list {
 	# Note we use Expect's spawn, not Tcl's exec, because with
 	# spawn we control when to wait for/reap the process.  That
-- 
2.1.0

[PATCH v4 2/4] gdb: testsuite: add new gdb_attach to check "attach" command

[Tiezhu Yang]

This commit adds new gdb_attach to centralize the failure checking of
"attach" command. Return 0 if attach failed, otherwise return 1.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 gdb/testsuite/lib/gdb.exp | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 89dcd0a..149a1c3 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5111,6 +5111,30 @@ proc can_spawn_for_attach { } {
     return 1
 }
 
+# Centralize the failure checking of "attach" command.
+# Return 0 if attach failed, otherwise return 1.
+
+proc gdb_attach { testpid args } {
+    parse_args {
+	{pattern ""}
+    }
+
+    if { [llength $args] != 0 } {
+	error "Unexpected arguments: $args"
+    }
+
+    gdb_test_multiple "attach $testpid" "attach" {
+	-re -wrap "Attaching to.*ptrace: Operation not permitted\\." {
+	    unsupported "$gdb_test_name (Operation not permitted)"
+	    return 0
+	}
+	-re -wrap "$pattern" {
+	    pass $gdb_test_name
+	    return 1
+	}
+    }
+}
+
 # Kill a progress previously started with spawn_wait_for_attach, and
 # reap its wait status.  PROC_SPAWN_ID is the spawn id associated with
 # the process.
-- 
2.1.0

Re: [PATCH v4 2/4] gdb: testsuite: add new gdb_attach to check "attach" command

[Simon Marchi]

On 2022-03-18 22:11, Tiezhu Yang wrote:
> This commit adds new gdb_attach to centralize the failure checking of
> "attach" command. Return 0 if attach failed, otherwise return 1.
> 
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  gdb/testsuite/lib/gdb.exp | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
> index 89dcd0a..149a1c3 100644
> --- a/gdb/testsuite/lib/gdb.exp
> +++ b/gdb/testsuite/lib/gdb.exp
> @@ -5111,6 +5111,30 @@ proc can_spawn_for_attach { } {
>      return 1
>  }
>  
> +# Centralize the failure checking of "attach" command.
> +# Return 0 if attach failed, otherwise return 1.
> +
> +proc gdb_attach { testpid args } {
> +    parse_args {
> +	{pattern ""}
> +    }
> +
> +    if { [llength $args] != 0 } {
> +	error "Unexpected arguments: $args"
> +    }
> +
> +    gdb_test_multiple "attach $testpid" "attach" {
> +	-re -wrap "Attaching to.*ptrace: Operation not permitted\\." {
> +	    unsupported "$gdb_test_name (Operation not permitted)"
> +	    return 0
> +	}
> +	-re -wrap "$pattern" {
> +	    pass $gdb_test_name
> +	    return 1
> +	}
> +    }
> +}

I guess we need a "return 0" at the end of the function, in case the test does fail?

Simon

Re: [PATCH v4 2/4] gdb: testsuite: add new gdb_attach to check "attach" command

[Tiezhu Yang]

On 03/21/2022 11:00 PM, Simon Marchi wrote:
> On 2022-03-18 22:11, Tiezhu Yang wrote:
>> This commit adds new gdb_attach to centralize the failure checking of
>> "attach" command. Return 0 if attach failed, otherwise return 1.
>>
>> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
>> ---
>>  gdb/testsuite/lib/gdb.exp | 24 ++++++++++++++++++++++++
>>  1 file changed, 24 insertions(+)
>>
>> diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
>> index 89dcd0a..149a1c3 100644
>> --- a/gdb/testsuite/lib/gdb.exp
>> +++ b/gdb/testsuite/lib/gdb.exp
>> @@ -5111,6 +5111,30 @@ proc can_spawn_for_attach { } {
>>      return 1
>>  }
>>
>> +# Centralize the failure checking of "attach" command.
>> +# Return 0 if attach failed, otherwise return 1.
>> +
>> +proc gdb_attach { testpid args } {
>> +    parse_args {
>> +	{pattern ""}
>> +    }
>> +
>> +    if { [llength $args] != 0 } {
>> +	error "Unexpected arguments: $args"
>> +    }
>> +
>> +    gdb_test_multiple "attach $testpid" "attach" {
>> +	-re -wrap "Attaching to.*ptrace: Operation not permitted\\." {
>> +	    unsupported "$gdb_test_name (Operation not permitted)"
>> +	    return 0
>> +	}
>> +	-re -wrap "$pattern" {
>> +	    pass $gdb_test_name
>> +	    return 1
>> +	}
>> +    }
>> +}
>
> I guess we need a "return 0" at the end of the function, in case the test does fail?
>
> Simon
>

OK, let me do it and then I will send v5 soon.

Thanks,
Tiezhu

[PATCH v4 3/4] gdb: testsuite: use gdb_attach to fix attach-pie-noexec.exp

[Tiezhu Yang]

If /proc/sys/kernel/yama/ptrace_scope is 1, when execute the following
command without superuser:

  make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"

we can see the following messages in gdb/testsuite/gdb.log:

  (gdb) attach 6500
  Attaching to process 6500
  ptrace: Operation not permitted.
  (gdb) PASS: gdb.base/attach-pie-noexec.exp: attach

It is obviously wrong, the expected result should be UNSUPPORTED in such
a case.

With this patch, we can see "Operation not permitted" in the log info,
and then we can do the following processes to test:
(1) set ptrace_scope as 0
    $ echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
    $ make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"
(2) use sudo
    $ sudo make check-gdb TESTS="gdb.base/attach-pie-noexec.exp"

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 gdb/testsuite/gdb.base/attach-pie-noexec.exp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/gdb/testsuite/gdb.base/attach-pie-noexec.exp b/gdb/testsuite/gdb.base/attach-pie-noexec.exp
index 4712824..33238db 100644
--- a/gdb/testsuite/gdb.base/attach-pie-noexec.exp
+++ b/gdb/testsuite/gdb.base/attach-pie-noexec.exp
@@ -59,7 +59,10 @@ set testpid [spawn_id_get_pid $test_spawn_id]
 
 gdb_start
 file delete -- $binfile
-gdb_test "attach $testpid" "Attaching to process $testpid\r\n.*" "attach"
+if { ![gdb_attach $testpid] } {
+    kill_wait_spawned_process $test_spawn_id
+    return
+}
 gdb_test "set architecture $arch" "The target architecture is set to \"$arch\"\\."
 gdb_test "info shared" "From\[ \t\]+To\[ \t\]+Syms Read\[ \t\]+Shared Object Library\r\n0x.*"
 
-- 
2.1.0

[PATCH v4 4/4] gdb: testsuite: use gdb_attach to fix jit-elf.exp

[Tiezhu Yang]

If /proc/sys/kernel/yama/ptrace_scope is 1, when execute the following
command without superuser:

  make check-gdb TESTS="gdb.base/jit-elf.exp"

we can see the following messages in gdb/testsuite/gdb.log:

  (gdb) attach 1650108
  Attaching to program: /home/yangtiezhu/build/gdb/testsuite/outputs/gdb.base/jit-elf/jit-elf-main, process 1650108
  ptrace: Operation not permitted.
  (gdb) FAIL: gdb.base/jit-elf.exp: attach: one_jit_test-2: break here 1: attach

use gdb_attach to fix the above issue, at the same time, the clean_reattach
proc should return a value to indicate whether it worked, and the callers
should return early as well on failure.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
 gdb/testsuite/gdb.base/jit-elf.exp | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/gdb/testsuite/gdb.base/jit-elf.exp b/gdb/testsuite/gdb.base/jit-elf.exp
index 8a4c5b7..4b75188 100644
--- a/gdb/testsuite/gdb.base/jit-elf.exp
+++ b/gdb/testsuite/gdb.base/jit-elf.exp
@@ -38,6 +38,7 @@ set jit_solib_basename jit-elf-solib
 set jit_solib_srcfile ${srcdir}/${subdir}/${jit_solib_basename}.c
 
 # Detach, restart GDB, and re-attach to the program.
+# Return 0 if attach failed, otherwise return 1.
 proc clean_reattach {} {
     global decimal gdb_prompt
     global main_binfile main_srcfile
@@ -57,18 +58,18 @@ proc clean_reattach {} {
 
     clean_restart ${main_binfile}
 
-    set test "attach"
-    gdb_test_multiple "attach $testpid" "$test" {
-	-re "Attaching to program.*.*main.*at .*$main_srcfile:.*$gdb_prompt $" {
-	    pass "$test"
-	}
+    if { ![gdb_attach $testpid \
+	      -pattern "main.*at .*$::main_srcfile:.*"] } {
+	return 0
     }
 
     gdb_test_no_output "set var wait_for_gdb = 0"
+    return 1
 }
 
 # Continue to LOCATION in the program.  If REATTACH, detach and
 # re-attach to the program from scratch.
+# Return 0 if clean_reattach failed, otherwise return 1.
 proc continue_to_test_location {location reattach} {
     global main_srcfile
 
@@ -76,9 +77,12 @@ proc continue_to_test_location {location reattach} {
     gdb_continue_to_breakpoint $location
     if {$reattach} {
 	with_test_prefix "$location" {
-	    clean_reattach
+	    if { ![clean_reattach] } {
+		return 0
+	    }
 	}
     }
+    return 1
 }
 
 proc one_jit_test {jit_solibs_target match_str reattach} {
@@ -114,7 +118,9 @@ proc one_jit_test {jit_solibs_target match_str reattach} {
 	gdb_continue_to_breakpoint "break here 0"
 
 
-	continue_to_test_location "break here 1" $reattach
+	if { ![continue_to_test_location "break here 1" $reattach] } {
+	    return
+	}
 
 	gdb_test "info function ^jit_function" "$match_str"
 
@@ -124,7 +130,9 @@ proc one_jit_test {jit_solibs_target match_str reattach} {
 	    gdb_test "maintenance info break"
 	}
 
-	continue_to_test_location "break here 2" $reattach
+	if { ![continue_to_test_location "break here 2" $reattach] } {
+	    return
+	}
 
 	# All jit librares must have been unregistered
 	gdb_test "info function jit_function" \
-- 
2.1.0

Re: [PATCH v4 0/4] gdb: add gdb_attach to fix failed testcases

[Kevin Buettner]

On Sat, 19 Mar 2022 10:11:23 +0800
Tiezhu Yang <yangtiezhu@loongson.cn> wrote:

> Please review this v4 patchset, thank you.

FWIW, my testing shows that this series fixes problems introduced
by commit 1dbf27133db.

It eliminates the new failure in gdb.base/run-after-attach.exp and
three failures in a new test that I'm working on.

Kevin

Re: [PATCH v4 0/4] gdb: add gdb_attach to fix failed testcases

[Tiezhu Yang]

On 03/22/2022 07:04 AM, Kevin Buettner wrote:
> On Sat, 19 Mar 2022 10:11:23 +0800
> Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
>
>> Please review this v4 patchset, thank you.
>
> FWIW, my testing shows that this series fixes problems introduced
> by commit 1dbf27133db.
>
> It eliminates the new failure in gdb.base/run-after-attach.exp and
> three failures in a new test that I'm working on.
>
> Kevin
>

Thank you for your test and feedback.

I will do a small change of patch #2 suggested by Simon,
and then I will send v5 soon.

Thanks,
Tiezhu