fork issue on 32bit

fork issue on 32bit

[Marco Atzeri]

Hi,

I am rebuilding the pure-ftpd server.
On 64bit I have no issue while testing the 32bit version on

  $ uname -svr
CYGWIN_NT-6.1-WOW 2.8.0(0.309/5/3) 2017-04-01 20:42

  I hit:

$ ./pure-ftpd -B
       0 [main] pure-ftpd 7960 E:\cygwin\usr\sbin\pure-ftpd.exe: *** 
fatal error in forked process - fork: can't reserve memory for parent 
stack 0x3B0000 - 0x5B0000, (child has 0x330000 - 0x530000), Win32 error 487
       0 [main] pure-ftpd 4752 fork: child -1 - forked process 7960 died 
unexpectedly, retry 0, exit code 0xC0000005, errno 11
Unable to start a standalone server - fork: Resource temporarily unavailable

I excluded AV interference as it happens also on Safe Mode.

The process memory area seems fine
00200000-00242000 rw-p 00000000 0000:0000 0  [win heap 1 grow]
00242000-00300000 ===p 00042000 0000:0000 0  [win heap 1 grow]
00300000-00301000 r--s 00000000 0000:0000 0
00310000-00312000 rw-p 00000000 0000:0000 0  [win heap 1 grow]
00312000-00320000 ===p 00002000 0000:0000 0  [win heap 1 grow]
00320000-00322000 rw-p 00000000 0000:0000 0
00330000-00331000 rw-p 00000000 0000:0000 0
00340000-00341000 r--s 00000000 0000:0000 0
00350000-00357000 r--s 00000000 0000:0000 0
00360000-00362000 rw-s 00000000 0000:0000 0

00380000-00384000 rw-p 00000000 0000:0000 0   [win heap 4 grow]
00384000-00390000 ===p 00004000 0000:0000 0   [win heap 4 grow]
003B0000-005A6000 ===p 00000000 0000:0000 0   [stack (tid 4604)]
005A6000-005A7000 rw-g 001F6000 0000:0000 0   [stack (tid 4604)]
005A7000-005B0000 rw-p 001F7000 0000:0000 0   [stack (tid 4604)]
005B0000-005E9000 ===p 00000000 0000:0000 0

I have same error on current package version pure-ftpd-1.0.45-1,
so or I missed to note the issue before (likely) or something
is changed in Cygwin in the meantime.

Any suggestion what to look for ?

Regards
Marco



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Re: fork issue on 32bit

[Marco Atzeri]

On 28/04/2017 20:38, Marco Atzeri wrote:
> Hi,
>
> I am rebuilding the pure-ftpd server.
> On 64bit I have no issue while testing the 32bit version on
>
>  $ uname -svr
> CYGWIN_NT-6.1-WOW 2.8.0(0.309/5/3) 2017-04-01 20:42
>
>  I hit:
>
> $ ./pure-ftpd -B
>       0 [main] pure-ftpd 7960 E:\cygwin\usr\sbin\pure-ftpd.exe: ***
> fatal error in forked process - fork: can't reserve memory for parent
> stack 0x3B0000 - 0x5B0000, (child has 0x330000 - 0x530000), Win32 error 487
>       0 [main] pure-ftpd 4752 fork: child -1 - forked process 7960 died
> unexpectedly, retry 0, exit code 0xC0000005, errno 11
> Unable to start a standalone server - fork: Resource temporarily
> unavailable
>
> I excluded AV interference as it happens also on Safe Mode.
>

for the archive, the issue is caused by linking with
   "-Wl,--dynamicbase"

removing the flag this problem go away.

It was also the reason of the puzzling debug issue
that was present on both 32bit and 64bit builds:

---------------- broken --------------
$ gdb ./pure-ftpd.exe
GNU gdb (GDB) (Cygwin 7.10.1-1) 7.10.1
[cut]
Reading symbols from ./pure-ftpd.exe...done.
(gdb) break main
Breakpoint 1 at 0x417e7e: file main.c, line 6.
(gdb) run
Starting program: 
/cygdrive/e/cyg_pub/devel/pure-ftpd/prova_1036/pure-ftpd-1.0.36-2.i686/build/src/pure-ftpd.exe
[New Thread 1932.0xd2c]
Warning:
Cannot insert breakpoint 1.
Cannot access memory at address 0x417e70

------------ good -------------------
$ gdb ./pure-ftpd.exe
GNU gdb (GDB) (Cygwin 7.10.1-1) 7.10.1
[cut]
Reading symbols from ./pure-ftpd.exe...done.
(gdb) break main
Breakpoint 1 at 0x417e7e: file main.c, line 6.
(gdb) run
Starting program: 
/cygdrive/e/cyg_pub/devel/pure-ftpd/prova_1036/pure-ftpd-1.0.36-3.i686/build/src/pure-ftpd.exe
[New Thread 768.0xb44]
[New Thread 768.0x234]
[New Thread 768.0xe24]
[New Thread 768.0x27c]

Breakpoint 1, main (argc=1, argv=0x28cc3c) at main.c:6
6           return pureftpd_start(argc, argv, NULL);


Regards
Marco


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