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Fwd: vdso
- From: vijay nag <vijunag at gmail dot com>
- To: Jan Kratochvil <jan dot kratochvil at redhat dot com>, gdb at sourceware dot org
- Date: Fri, 5 Jul 2013 11:42:29 +0530
- Subject: Fwd: vdso
- References: <CAKhyrx_TULNrWwSJ0zPq4tgd8MOpkhSRYZfbMRFcRLw7P0mj4Q at mail dot gmail dot com> <20130703084207 dot GA598 at host2 dot jankratochvil dot net> <CAKhyrx9xNG6xEtVf51ig-dC93=C9vrzgi98RzjA4QLyfuE+hkw at mail dot gmail dot com> <20130703090259 dot GA1854 at host2 dot jankratochvil dot net> <CAKhyrx8nSOR4Sq2K3XbyVytUnQMyn42Xpbo1aX0=Df4r5Pebtw at mail dot gmail dot com> <CAKhyrx_9fSc5wMaXaX76bFOPJbuVFttDNJ-YDa28wz5obJHQyQ at mail dot gmail dot com> <20130703144857 dot GA27367 at host2 dot jankratochvil dot net> <CAKhyrx8GCE7bYeZe9gnNT_aZN74oM--kd_oZr1+cjqt67oOzVQ at mail dot gmail dot com> <20130704061052 dot GA19661 at host2 dot jankratochvil dot net> <CAKhyrx8pAR9aKC1=-_HnwJ=ssb4B7LGUYM6CRqxY68xx+duprA at mail dot gmail dot com>
---------- Forwarded message ----------
From: vijay nag <vijunag@gmail.com>
Date: Fri, Jul 5, 2013 at 11:38 AM
Subject: Re: vdso
To: Jan Kratochvil <jan.kratochvil@redhat.com>
On Thu, Jul 4, 2013 at 11:40 AM, Jan Kratochvil
<jan.kratochvil@redhat.com> wrote:
> On Wed, 03 Jul 2013 17:23:39 +0200, vijay nag wrote:
>> On Wednesday, July 3, 2013, Jan Kratochvil <jan.kratochvil@redhat.com> wrote:
>> > This warning is tracked as:
>> > http://sourceware.org/bugzilla/show_bug.cgi?id=14466
>> >
>> > and it is harmless, it should not affect functionality/symbols of GDB.
>> >
>> >
>> > Jan
>> >
>> Are you suggesting me that it could be a problem with glibc ?
>
> No.
>
>
> Jan
The function linux_proc_xfer_partial() is returning result zero when
trying to pread64 /proc/<pid>/mem and errno is set to -EIO.
Does that mean kernel doesn't support pread64 on /proc/xxx/mem files ?
gdb) l
4392
4393 /* We could keep this file open and cache it - possibly one per
4394 thread. That requires some juggling, but is even faster. */
4395 sprintf (filename, "/proc/%d/mem", PIDGET (inferior_ptid));
4396 fd = open (filename, O_RDONLY | O_LARGEFILE);
4397 if (fd == -1)
4398 return 0;
4399
4400 /* If pread64 is available, use it. It's faster if the kernel
4401 supports it (only one syscall), and it's 64-bit safe even on
(gdb) l
4402 32-bit platforms (for instance, SPARC debugging a SPARC64
4403 application). */
4404 #ifdef HAVE_PREAD64
4405 if (pread64 (fd, readbuf, len, offset) != len)
4406 #else
4407 if (lseek (fd, offset, SEEK_SET) == -1 || read (fd, readbuf,
len) != len)
4408 #endif
4409 ret = 0;
4410 else
4411 ret = len;
(gdb) p *__errno_location()
$18 = 5
(gdb)