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From: Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
To: Oren Laadan <orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
	Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	Linus Torvalds <torvalds-3NddpPZAyC0@public.gmane.org>,
	Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Subject: Re: [RFC v10][PATCH 09/13] Restore open file descriprtors
Date: Mon, 01 Dec 2008 12:54:33 -0800	[thread overview]
Message-ID: <1228164873.2971.95.camel@nimitz> (raw)
In-Reply-To: <49344C11.6090204-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>

On Mon, 2008-12-01 at 15:41 -0500, Oren Laadan wrote:
> >>> +   fd = cr_attach_file(file);      /* no need to cleanup 'file' below */
> >>> +   if (fd < 0) {
> >>> +           filp_close(file, NULL);
> >>> +           ret = fd;
> >>> +           goto out;
> >>> +   }
> >>> +
> >>> +   /* register new <objref, file> tuple in hash table */
> >>> +   ret = cr_obj_add_ref(ctx, file, parent, CR_OBJ_FILE, 0);
> >>> +   if (ret < 0)
> >>> +           goto out;
> >> Who said that file still exists at that point?
> 
> Correct. This call should move higher up befor ethe call to cr_attach_file()

Is that sufficient?  It seems like we're depending on the fd's reference
to the 'struct file' to keep it valid in the hash.  If something happens
to the fd (like the other thread messing with it) the 'struct file' can
still go away.

Shouldn't we do another get_file() for the hash's reference?

-- Dave

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  parent reply	other threads:[~2008-12-01 20:54 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-27  1:04 [RFC v10][PATCH 00/13] Kernel based checkpoint/restart Oren Laadan
     [not found] ` <1227747884-14150-1-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-27  1:04   ` [RFC v10][PATCH 01/13] Create syscalls: sys_checkpoint, sys_restart Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 02/13] Checkpoint/restart: initial documentation Oren Laadan
     [not found]     ` <1227747884-14150-3-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:45       ` Al Viro
     [not found]         ` <20081128104554.GP28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 18:15           ` Dave Hansen
2008-11-27  1:04   ` [RFC v10][PATCH 03/13] General infrastructure for checkpoint restart Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 04/13] x86 support for checkpoint/restart Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 05/13] Dump memory address space Oren Laadan
     [not found]     ` <1227747884-14150-6-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:53       ` Al Viro
     [not found]         ` <20081128105351.GQ28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 18:00           ` Dave Hansen
2008-12-01 20:57             ` Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 06/13] Restore " Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 07/13] Infrastructure for shared objects Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 08/13] Dump open file descriptors Oren Laadan
     [not found]     ` <1227747884-14150-9-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 10:19       ` Al Viro
     [not found]         ` <20081128101919.GO28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 17:47           ` Dave Hansen
2008-12-01 20:23             ` Oren Laadan
     [not found]               ` <493447DD.7010102-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 20:51                 ` Dave Hansen
2008-12-01 21:02                   ` Linus Torvalds
     [not found]                     ` <alpine.LFD.2.00.0812011258390.3256-nfNrOhbfy2R17+2ddN/4kux8cNe9sq/dYPYVAmT7z5s@public.gmane.org>
2008-12-01 21:25                       ` Dave Hansen
2008-12-01 21:20                   ` Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 09/13] Restore open file descriprtors Oren Laadan
     [not found]     ` <1227747884-14150-10-git-send-email-orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-11-28 11:27       ` Al Viro
     [not found]         ` <20081128112745.GR28946-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2008-12-01 19:22           ` Dave Hansen
2008-12-01 20:41             ` Oren Laadan
     [not found]               ` <49344C11.6090204-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 20:54                 ` Dave Hansen [this message]
2008-12-01 21:00                   ` Oren Laadan
     [not found]                     ` <49345086.4-eQaUEPhvms7ENvBUuze7eA@public.gmane.org>
2008-12-01 21:07                       ` Dave Hansen
2008-12-02  1:31                         ` Dave Hansen
2008-12-02  1:12                       ` Dave Hansen
2008-11-27  1:04   ` [RFC v10][PATCH 10/13] External checkpoint of a task other than ourself Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 11/13] Track in-kernel when we expect checkpoint/restart to work Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 12/13] Checkpoint multiple processes Oren Laadan
2008-11-27  1:04   ` [RFC v10][PATCH 13/13] Restart " Oren Laadan
2008-12-03 23:58   ` [RFC v10][PATCH 00/13] Kernel based checkpoint/restart Serge E. Hallyn

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