[PATCH-2.4] allow core files bigger than 2GB

[PATCH-2.4] allow core files bigger than 2GB

[Willy Tarreau]

Marcelo,

I think I have not sent you this one. It looks valid to me.
I can queue it in -upstream if you prefer to pull everything
at once.

Cheers,
Willy
--

>From nobody Mon Sep 17 00:00:00 2001
From: Javier Olivares <jolivares@gigablast.com>
Date: Wed, 31 May 2006 00:32:59 +0200
Subject: [PATCH] bug fix for 2GB core limit in 2.4

We were having problems when running programs that used over 2GB of ram
not being able to generate core files over 2GB, these are some very
simple changes that fixed the problem.

The changes have been running on many Debian systems for a couple of
months.  Valid core files just over 3GB have been created without any
problem.

---

 fs/binfmt_elf.c |    2 +-
 fs/exec.c       |    3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

04d0e7780b49eeef578ceec8901c71ac356df504
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index b0ad905..6c2f357 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1026,7 +1026,7 @@ static int dump_write(struct file *file,
 	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
 }
 
-static int dump_seek(struct file *file, off_t off)
+static int dump_seek(struct file *file, loff_t off)
 {
 	if (file->f_op->llseek) {
 		if (file->f_op->llseek(file, off, 0) != off)
diff --git a/fs/exec.c b/fs/exec.c
index f196e7e..aec92be 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1148,7 +1148,8 @@ int do_coredump(long signr, struct pt_re
 		goto fail;
 
  	format_corename(corename, core_pattern, signr);
-	file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW, 0600);
+	file = filp_open(corename,
+	                 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600);
 	if (IS_ERR(file))
 		goto fail;
 	inode = file->f_dentry->d_inode;
-- 
1.3.3

Re: [PATCH-2.4] allow core files bigger than 2GB

[Arjan van de Ven]

On Sat, 2006-06-17 at 23:45 +0200, Willy Tarreau wrote:
> Marcelo,
> 
> I think I have not sent you this one. It looks valid to me.
> I can queue it in -upstream if you prefer to pull everything
> at once.


Hi,

This is a rather complex issue, to the point that your patch is not
sufficient actually. While it will create a core file, it's not really a
good one, and there are some nasty other issues with it (esp on 64 bit
systems). The enterprise distro kernels have a more complete patch for
this (I'm pretty sure both RH and SUSE have fundamentally the same patch
for this), if you really want this functionality I suggest getting the
patch from either of those distros to get the full thing (there's some
security angle to this even iirc).

Greetings, 
   Arjan van de Ven

Re: [PATCH-2.4] allow core files bigger than 2GB

[Willy Tarreau]

On Sun, Jun 18, 2006 at 08:09:53AM +0200, Arjan van de Ven wrote:
> On Sat, 2006-06-17 at 23:45 +0200, Willy Tarreau wrote:
> > Marcelo,
> > 
> > I think I have not sent you this one. It looks valid to me.
> > I can queue it in -upstream if you prefer to pull everything
> > at once.
> 
> 
> Hi,
> 
> This is a rather complex issue, to the point that your patch is not
> sufficient actually. While it will create a core file, it's not really a
> good one, and there are some nasty other issues with it (esp on 64 bit
> systems). The enterprise distro kernels have a more complete patch for
> this (I'm pretty sure both RH and SUSE have fundamentally the same patch
> for this), if you really want this functionality I suggest getting the
> patch from either of those distros to get the full thing (there's some
> security angle to this even iirc).

Thanks for notifying us about this Arjan. I've checked in RHEL patches
and found that this is done in 2.4.21-binfmt-elf.patch with a detailed
explanation. The patch is rather large, not to say invasive. I believe
it serves other purposes but it seems to me that it will still be
invasive enough not to be merged into 2.4 mainline right now.

> Greetings, 
>    Arjan van de Ven

Regards,
Willy