Re: vn_fullpath: 0xc85e24a0 is not locked but should be

At Thu, 11 Dec 2003 23:14:50 -0500 (EST),
Robert Watson wrote:
> Ah, you're still runing with the VFS lock debugging :-).  Indeed, it looks
> like a vn_lock() and unlock of p->p_textvp is missing in
> procfs_doprocfile(), even though that likely would violate the VFS lock
> order.  The attached (untested) patch might well fix it, but might not be
> right -- I'm not sure that curthread holds a valid reference to
> p->p_textvp that can't evaporate during these operations.  I'm not sure
> the proc reference stuff protects us properly here, but John would know
> (CC'd). 
> 
> Index: procfs.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/fs/procfs/procfs.c,v
> retrieving revision 1.9
> diff -u -r1.9 procfs.c
> --- procfs.c	17 Apr 2003 22:12:12 -0000	1.9
> +++ procfs.c	12 Dec 2003 04:13:10 -0000
> _at__at_ -70,7 +70,9 _at__at_
>  	char *fullpath = "unknown";
>  	char *freepath = NULL;
>  
> +	vn_lock(p->p_textvp, LK_EXCLUSIVE | LK_RETRY, td);
>  	vn_fullpath(td, p->p_textvp, &fullpath, &freepath);
> +	VOP_UNLOCK(p->p_textvp, 0, td);
>  	sbuf_printf(sb, "%s", fullpath);
>  	if (freepath)
>  		free(freepath, M_TEMP);

Okay, I'll wait without DEBUG_VFS_LOCKS until fix is committed.

At Thu, 11 Dec 2003 23:15:03 -0700 (MST),
M. Warner Losh wrote:
> : # Why I got so many panics?  :-(
> 
> Because after you get 10,000 of them, you are forced to serve on core
> :-)

I hope I won't get more. :-)


-- 
Jun Kuriyama <kuriyama_at_imgsrc.co.jp> // IMG SRC, Inc.
             <kuriyama_at_FreeBSD.org> // FreeBSD Project