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Date: Fri, 12 Jun 2009 10:51:00 -0000
From: "kirill at shutemov dot name" <sourceware-bugzilla@sourceware.org>
To: gdb-prs@sourceware.org
Message-ID: <20090612105104.10267.kirill@shutemov.name>
Reply-To: sourceware-bugzilla@sourceware.org
Subject: [Bug gdb/10267] New: ERESTART_RESTARTBLOCK and function calling
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I've got bug in handling ERESTART_RESTARTBLOCK. Kernel version is 2.6.28.

Steps to reproduce:
1. Attach to process while it's in a syscall which use ERESTART_RESTARTBLOCK on
interrupt. The easiest way is to attach to process which is in nanosleep().
2. Run a syscall in context.
3. Continue the process.

Results:
Syscall(nanosleep) return error code 516(ERESTART_RESTARTBLOCK). It's
kernel's internal error code and should never appear at userspace.

It seems ARM-related since I can't reproduce it on x86. I'm not sure if it's
kernel or gdb bug. Any ideas?

Example:
$ cat test.c
#include <errno.h>
#include <stdio.h>
#include <time.h>

int main()
{
       struct timespec ts;
       int ret;

       ts.tv_sec = 100;
       ts.tv_nsec = 0;

       errno = 0;
       ret = nanosleep(&ts, NULL);
       printf("ret: %d, errno: %d\n", ret, errno);

       return 0;
}
$ gcc test.c
$ ./a.out &
$ gdb -p "$(pidof a.out)" -ex 'call getuid()' -ex 'c' -ex 'quit'
GNU gdb (GDB) 6.8.50.20090417-debian
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "arm-linux-gnueabi".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Attaching to process 6136
Reading symbols from /root/a.out...(no debugging symbols found)...done.
Reading symbols from /lib/libc.so.6...Reading symbols from
/usr/lib/debug/lib/libc-2.5.so...(no debugging symbols found)...done.
(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.3...Reading symbols from
/usr/lib/debug/lib/ld-2.5.so...(no debugging symbols found)...done.
(no debugging symbols found)...done.
Loaded symbols for /lib/ld-linux.so.3
0x400bf97c in nanosleep () from /lib/libc.so.6
0x400bf97c <nanosleep+28>:      mov     r7, r12
$1 = 0
Continuing.
ret: -1, errno: 516

Program exited normally.
[1] + Done                       ./a.out

-- 
           Summary: ERESTART_RESTARTBLOCK and function calling
           Product: gdb
           Version: 6.8
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: kirill at shutemov dot name
                CC: gdb-prs at sourceware dot org
 GCC build triplet: arm-linux-gnueabi
  GCC host triplet: arm-linux-gnueabi
GCC target triplet: arm-linux-gnueabi


http://sourceware.org/bugzilla/show_bug.cgi?id=10267

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