Re: [Feature Request?] Inline compression of process core dumps

[Randy Dunlap <randy.dunlap@oracle.com>]

Andi Kleen wrote:
> Alan Cox <alan@lxorguk.ukuu.org.uk> writes:
>
> > > I saw that too, and unfortunately I don't know what what that condition 
> > > represents, either.  It's the only other element in that if statement 
> > > that could make it take that path, so I'm assuming that's part of the 
> > > problem.
> > Multiple mm's mean multiple threads with a different set of mappings,
> > which would fit for UML. Either way there should be a check for !pipe
> > before appending the pid
>
> Here's a patch. It just doesn't do any formatting for the pipe case.
>
> -Andi
>
> Fix core to pipe for multithreaded processes
>
> I also removed the BKL around format_corename because it seems unneeded.

so either the comment just above lock_kernel() should be removed, or
it's correct and lock_kernel()/unlock_kernel() should stay.

	/*
	 * lock_kernel() because format_corename() is controlled by sysctl, which
	 * uses lock_kernel()
	 */
	lock_kernel();
	format_corename(corename, core_pattern, signr);
	unlock_kernel();


> Signed-off-by: Andi Kleen <ak@suse.de>
>
> Index: linux-2.6.21-rc3-test/fs/exec.c
> ===================================================================
> --- linux-2.6.21-rc3-test.orig/fs/exec.c
> +++ linux-2.6.21-rc3-test/fs/exec.c
> @@ -1501,9 +1501,6 @@ int do_coredump(long signr, int exit_cod
>  	 * lock_kernel() because format_corename() is controlled by sysctl, which
>  	 * uses lock_kernel()
>  	 */
> - 	lock_kernel();
> -	format_corename(corename, core_pattern, signr);
> -	unlock_kernel();
>   	if (corename[0] == '|') {
>  		/* SIGPIPE can happen, but it's just never processed */
>   		if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
> @@ -1512,10 +1509,12 @@ int do_coredump(long signr, int exit_cod
>   			goto fail_unlock;
>   		}
>  		ispipe = 1;
> - 	} else
> + 	} else {
> +		format_corename(corename, core_pattern, signr);
>   		file = filp_open(corename,
>  				 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
>  				 0600);
> +	}
>  	if (IS_ERR(file))
>  		goto fail_unlock;
>  	inode = file->f_path.dentry->d_inode;


--
~Randy
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