[Bug ada/40285] New: Including Ada.Real_Time.Timing_Events breaks signal handling
This issue has also been discussed on the comp.lang.ada newsgroup, see [1] for details. Signal-handling using a protected type as handler is not possible any more if an application includes the Ada.Real_Time.Timing_Events package. It's not necessary to actually use types from the package, including it is enough to break signal handling. I wrote a small reproducer to illustrate the problem, the files are attached. The protected object Signal_Handler defined in the package Handlers is used as a signal handler, which can be attached to a specific interrupt/signal. The Signal_Handler type is used in the small test application implemented as procedure Interrupt_Problem in the interrupt_problem.adb file. As expected, when sending SIGTERM (or other signals) to the running 'Interrupt_Problem' process "Interrupt received ..." is displayed. When the Ada.Real_Time.Timing_Events package is included, this mechanism breaks. The signal handler is not invoked any more when signals are sent to a running 'Interrupt_Problem' process, the Handler.Wait entry is not triggered. The problem seems to have various characteristics on different architectures, see the newsgroup thread [1]. gnatgcc -v output: Using built-in specs. Target: i486-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Debian 4.3.2-1.1' --with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3 --program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --enable-targets=all --enable-cld --enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu Thread model: posix gcc version 4.3.2 (Debian 4.3.2-1.1) -- [1] - http://groups.google.com/group/comp.lang.ada/browse_thread/thread/e69505d5161d7d41 -- Summary: Including Ada.Real_Time.Timing_Events breaks signal handling Product: gcc Version: 4.3.2 Status: UNCONFIRMED Severity: normal Priority: P3 Component: ada AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: reet at codelabs dot ch GCC build triplet: i486-linux-gnu GCC host triplet: i486-linux-gnu GCC target triplet: i486-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40285
[Bug ada/40285] Including Ada.Real_Time.Timing_Events breaks signal handling
--- Comment #1 from reet at codelabs dot ch 2009-05-28 23:01 --- Created an attachment (id=17926) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17926&action=view) Simple application which uses a protected type for signal handling. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40285
[Bug ada/40285] Including Ada.Real_Time.Timing_Events breaks signal handling
--- Comment #2 from reet at codelabs dot ch 2009-05-28 23:02 --- Created an attachment (id=17927) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17927&action=view) Handlers package spec. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40285
[Bug ada/40285] Including Ada.Real_Time.Timing_Events breaks signal handling
--- Comment #3 from reet at codelabs dot ch 2009-05-28 23:03 --- Created an attachment (id=17928) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=17928&action=view) Handlers package body. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40285
[Bug ada/39441] New: Discriminant & interface not implemented by full type (RM-2005 7.3 (7.3/2))
Given the following package spec:
package Full_View is
type Base_Type (Num : Integer) is tagged private;
type Base_Interface is interface;
type New_Type is new Base_Type (Num => 11)
and Base_Interface with private;
private
type Base_Type (Num : Integer) is tagged record
My_Number : Integer := Num;
end record;
type New_Type is new Base_Type (Num => 11) and
Base_Interface with null record;
end Full_View;
Trying to compile this with gcc 4.3.2 in Debian/Lenny results in the following
error:
full_view.ads:7:09: interface "Base_Interface" not implemented by full
type (RM-2005 7.3 (7.3/2))
Verbose output:
$ gcc -v -c full_view.ads
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.3.2-1.1'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --enable-targets=all --enable-cld
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
gcc version 4.3.2 (Debian 4.3.2-1.1)
COLLECT_GCC_OPTIONS='-v' '-c' '-mtune=generic'
/usr/lib/gcc/i486-linux-gnu/4.3.2/gnat1 -quiet -dumpbase full_view.ads
-mtune=generic full_view.ads -o /tmp/cchU6wbD.s
full_view.ads:7:09: interface "Base_Interface" not implemented by full type
(RM-2005 7.3 (7.3/2))
When removing the (Num => 11) discrimant initialization or the Base_Interface
interface from the New_Type type extension, the code compiles fine.
Seems to me that the consistency check of the partial and full view of a tagged
type covering interfaces does not work with discriminants.
- reto
--
Summary: Discriminant & interface not implemented by full type
(RM-2005 7.3 (7.3/2))
Product: gcc
Version: 4.3.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: reet at codelabs dot ch
GCC build triplet: i486-linux-gnu
GCC host triplet: i486-linux-gnu
GCC target triplet: i486-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39441
[Bug ada/41383] New: Timing_Events: Event time not cleared after Cancel_Handler
ARM D.15 about Ada.Real_Time.Timing_Events states:
9/2 An object of type Timing_Event is said to be set if it is associated
with a non-null value of type Timing_Event_Handler and cleared
otherwise. All Timing_Event objects are initially cleared.
17/2 The procedure Cancel_Handler clears the event if it is set.
Cancelled is assigned True if the event was set prior to it being
cleared; otherwise it is assigned False.
18/2 The function Time_Of_Event returns the time of the event if the
event is set; otherwise it returns Real_Time.Time_First.
There's a bug in the Cancel_Handler() procedure, because the event time remains
set and is not reset to Ada.Real_Time.Time_First (as required by 18/2).
Here is a small reproducer:
--
with Ada.Real_Time.Timing_Events;
package Timers is
use Ada.Real_Time.Timing_Events;
protected type Timer_Type is
procedure Setup (At_Time : Ada.Real_Time.Time);
function Get_Time return Ada.Real_Time.Time;
procedure Stop (Status : out Boolean);
private
procedure Handle (Event : in out Timing_Event);
Event : Timing_Event;
end Timer_Type;
end Timers;
--
package body Timers is
protected body Timer_Type is
function Get_Time return Ada.Real_Time.Time is
begin
return Event.Time_Of_Event;
end Get_Time;
procedure Handle (Event : in out Timing_Event) is
begin
null;
end Handle;
procedure Setup (At_Time : Ada.Real_Time.Time) is
begin
Event.Set_Handler (At_Time => At_Time,
Handler => Handle'Access);
end Setup;
procedure Stop (Status : out Boolean) is
begin
Event.Cancel_Handler (Cancelled => Status);
end Stop;
end Timer_Type;
end Timers;
--
with Ada.Text_IO;
with Ada.Real_Time;
with Timers;
procedure Cancel_Handler is
use Ada.Real_Time;
Handler : Timers.Timer_Type;
Timer : constant Time := Clock + Minutes (60);
begin
if Handler.Get_Time = Time_First then
Ada.Text_IO.Put_Line ("Time is Time_First ...");
end if;
Handler.Setup (At_Time => Timer);
if Handler.Get_Time = Timer then
Ada.Text_IO.Put_Line ("Handler set ...");
end if;
declare
Stopped : Boolean := False;
begin
Handler.Stop (Status => Stopped);
if Stopped then
Ada.Text_IO.Put_Line ("Timer cancelled ...");
if Handler.Get_Time = Timer then
Ada.Text_IO.Put_Line ("Why is the time still set then?");
end if;
end if;
end;
end Cancel_Handler;
--
Summary: Timing_Events: Event time not cleared after
Cancel_Handler
Product: gcc
Version: 4.4.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: reet at codelabs dot ch
GCC build triplet: i486-linux-gnu
GCC host triplet: i486-linux-gnu
GCC target triplet: i486-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41383
[Bug ada/43598] New: GNAT.Expect.Non_Blocking_Spawn double free or corruption
(forwarding Debian bug #575954)
Under some conditions, using GNAT.Expect.Non_Blocking_Spawn in
conjunction with GNAT.Expect.Close leads to memory corruption on amd64.
Given the following small reproducer:
-- expect_test.adb
with Ada.Text_IO;
with GNAT.Expect;
with GNAT.OS_Lib;
with GNAT.Regpat;
procedure Expect_Test is
use GNAT.Expect;
Fd : Process_Descriptor;
Command : constant String := "./print_file";
Arg_List : GNAT.OS_Lib.Argument_List (1 .. 0);
Result : Expect_Match;
Match: GNAT.Regpat.Match_Array (0 .. 0);
begin
Non_Blocking_Spawn
(Descriptor => Fd,
Command => Command,
Args=> Arg_List,
Buffer_Size => 128,
Err_To_Out => True);
Expect
(Descriptor => Fd,
Result => Result,
Regexps => Regexp_Array'
(+"END TESTS(.*)FAILED",
+"END TESTS(.*)PASSED"),
Matched => Match,
Timeout => 10);
Ada.Text_IO.Put_Line ("Terminated");
Ada.Text_IO.Put_Line (Expect_Out (Descriptor => Fd));
Ada.Text_IO.Put_Line ("Buffer len " &
Expect_Out (Descriptor => Fd)'Length'Img);
Close (Descriptor => Fd);
exception
when Process_Died =>
Ada.Text_IO.Put_Line ("Process died");
Ada.Text_IO.Put_Line (Expect_Out (Descriptor => Fd));
Close (Descriptor => Fd);
end Expect_Test;
-- print_file.adb
with Ada.Text_IO;
procedure Print_File is
Filename : constant String := "output";
File : Ada.Text_IO.File_Type;
begin
Ada.Text_IO.Open (File => File,
Mode => Ada.Text_IO.In_File,
Name => Filename);
while not Ada.Text_IO.End_Of_File (File => File) loop
delay 0.001;
Ada.Text_IO.Put_Line (Ada.Text_IO.Get_Line (File => File));
end loop;
Ada.Text_IO.Close (File => File);
end Print_File;
-- output
END TESTS...: PASSED
--
Running the expect_test binary on amd64 results in memory corruption. As
it seems this only happens if the following conditions are met:
* the binary spawned produces more output than the expect buffer size
This should not matter because Non_Blocking_Spawn is expected to discard
old characters:
"The expect buffer associated with that process can contain at most
Buffer_Size characters. Older characters are simply discarded when this
buffer is full."
* the spawned binary uses file IO
* the code sleeps between the text output cycles
Tests:
* gnat 4.3.2:
*** glibc detected *** ./obj/expect_test: double free or corruption
(!prev): 0x006040a0 ***
* gnat 4.4.3:
*** glibc detected *** ./obj/expect_test: free(): invalid next size
(fast): 0x00605090 ***
The bug is also present with the tip of the gcc-4_4-branch (Subversion
revision 157750) from upstream (verified by Ludovic Brenta).
Full gdb backtrace with gnat 4.3.2:
#0 0x7f9502737ed5 in raise () from /lib/libc.so.6
No symbol table info available.
#1 0x7f95027393f3 in abort () from /lib/libc.so.6
No symbol table info available.
#2 0x7f9502774388 in __libc_message () from /lib/libc.so.6
No symbol table info available.
#3 0x7f9502779928 in malloc_printerr () from /lib/libc.so.6
No symbol table info available.
#4 0x7f950277ba36 in free () from /lib/libc.so.6
No symbol table info available.
#5 0x7f9502ee53a5 in <__gnat_free> (ptr=6308000) at s-memory.adb:117
No locals.
#6 0x7f9502e670af in gnat.expect.close (descript...@0x7fffbe50) at
g-expect.adb:227
current_filter =
next_filter =
#7 0x00402ff7 in _ada_expect_test ()
No locals.
The complete reproducer code can be downloaded at [1].
- reto
[1] - http://www.codelabs.ch/~reet/reproducers/gnat-expect.tar.bz2
--
Summary: GNAT.Expect.Non_Blocking_Spawn double free or corruption
Product: gcc
Version: 4.4.4
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: reet at codelabs dot ch
GCC build triplet: x86_64-linux-gnu
GCC host triplet: x86_64-linux-gnu
GCC target triplet: x86_64-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43598
