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From: Thierry Reding <thierry.reding@gmail.com>
To: Paul Moore <pmoore@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Sabrina Dubroca <sd@queasysnail.net>,
	Guenter Roeck <linux@roeck-us.net>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	linux-next@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-audit@redhat.com,
	Richard Guy Briggs <rgb@redhat.com>
Subject: Re: linux-next: Tree for Jan 20 -- Kernel panic - Unable to mount root fs
Date: Wed, 21 Jan 2015 16:39:12 +0100	[thread overview]
Message-ID: <20150121153910.GD22884@ulmo.nvidia.com> (raw)
In-Reply-To: <9422577.FVVyjQBZjy@sifl>

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On Wed, Jan 21, 2015 at 10:24:11AM -0500, Paul Moore wrote:
> On Wednesday, January 21, 2015 03:42:16 PM Thierry Reding wrote:
> > On Wed, Jan 21, 2015 at 12:05:39PM +0100, Sabrina Dubroca wrote:
> > > 2015-01-21, 04:36:38 +0000, Al Viro wrote:
> > > > On Tue, Jan 20, 2015 at 08:01:26PM -0800, Guenter Roeck wrote:
> > > > > With this patch:
> > > > > 
> > > > > sys_mkdir .:40775 returned -17
> > > > > sys_mkdir usr:40775 returned 0
> > > > > sys_mkdir usr/lib:40775 returned 0
> > > > > sys_mkdir usr/share:40755 returned 0
> > > > > sys_mkdir usr/share/udhcpc:40755 returned 0
> > > > > sys_mkdir usr/bin:40775 returned 0
> > > > > sys_mkdir usr/sbin:40775 returned 0
> > > > > sys_mkdir mnt:40775 returned 0
> > > > > sys_mkdir proc:40775 returned 0
> > > > > sys_mkdir root:40775 returned 0
> > > > > sys_mkdir lib:40775 returned 0
> > > > > sys_mkdir lib/modules:40775 returned 0
> > > > > ...
> > > > > 
> > > > > and the problem is fixed.
> > > 
> > > This patch also works for me.
> > > 
> > > > ... except that it simply confirms that something's fishy with
> > > > getname_kernel() of ->name of struct filename returned by getname(). 
> > > > IOW, I still do not understand the mechanism of breakage there.
> > > 
> > > I'm not so sure about that.  I tried to copy name to a new string in
> > > do_path_lookup and that didn't help.
> > > 
> > > Now, I've removed the
> > > 
> > >         putname(filename);
> > > 
> > > line from do_path_lookup and I don't get the panic.
> > 
> > That would indicate that somehow the refcount got unbalanced. Looking
> > more closely it seems like the various audit_*() function do take a
> > reference, but maybe that's not enough.
> 
> I'm thinking the same thing and I think the problem may be that 
> __audit_reusename() is not bumping the filename->refcnt.  Can someone who is 
> seeing this problem bump the refcnt in __audit_reusename()?
> 
>   struct filename *
>   __audit_reusename(const __user char *uptr)
>   {
>         struct audit_context *context = current->audit_context;
>         struct audit_names *n;
> 
>         list_for_each_entry(n, &context->names_list, list) {
>                 if (!n->name)
>                         continue;
>                 if (n->name->uptr == uptr) {
> +                       n->name->refcnt++;
>                         return n->name;
>                 }
>         }
>         return NULL;
>   }

That doesn't seem to help, at least in my case.

Thierry

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  reply	other threads:[~2015-01-21 15:39 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20150120185308.53f4af4e@canb.auug.org.au>
2015-01-20 16:56 ` linux-next: Tree for Jan 20 -- Kernel panic - Unable to mount root fs Sabrina Dubroca
2015-01-20 17:39   ` Paul Moore
2015-01-20 17:51     ` Sabrina Dubroca
2015-01-20 19:54       ` Al Viro
2015-01-20 20:45         ` Sabrina Dubroca
2015-01-20 21:02           ` Al Viro
2015-01-20 21:38             ` Sabrina Dubroca
2015-01-20 21:58               ` Al Viro
2015-01-20 22:08                 ` Sabrina Dubroca
2015-01-20 22:13                   ` Guenter Roeck
2015-01-20 22:50                     ` Al Viro
2015-01-20 23:17                       ` Al Viro
2015-01-20 23:27                         ` Sabrina Dubroca
2015-01-21  0:04                           ` Paul Moore
2015-01-21  0:14                             ` Paul Moore
2015-01-21  0:41                               ` Al Viro
2015-01-21  2:44                                 ` Guenter Roeck
2015-01-21  3:36                                   ` Al Viro
2015-01-21  4:01                                     ` Guenter Roeck
2015-01-21  4:36                                       ` Al Viro
2015-01-21 11:05                                         ` Sabrina Dubroca
2015-01-21 13:32                                           ` Guenter Roeck
2015-01-21 18:29                                             ` Al Viro
2015-01-21 19:06                                               ` Guenter Roeck
2015-01-21 20:06                                                 ` Al Viro
2015-01-21 21:03                                                   ` Guenter Roeck
2015-01-21 21:28                                                     ` Al Viro
2015-01-21 21:38                                                       ` Guenter Roeck
2015-01-21 21:40                                                       ` Sabrina Dubroca
2015-01-21 21:54                                                       ` Paul Walmsley
2015-01-22  2:28                                                       ` Paul Moore
2015-01-22  4:12                                                         ` Al Viro
2015-01-22  4:49                                                           ` Paul Moore
2015-01-21 21:30                                                     ` Sabrina Dubroca
2015-01-21 14:42                                           ` Thierry Reding
2015-01-21 15:24                                             ` Paul Moore
2015-01-21 15:39                                               ` Thierry Reding [this message]
2015-01-21 15:54                                                 ` Sabrina Dubroca
2015-01-21 16:16                                                   ` Paul Moore
2015-01-21 17:38                                                     ` Al Viro
2015-01-21 17:51                                                       ` Guenter Roeck
2015-01-21 16:21                                                   ` Guenter Roeck
2015-01-21 15:06                                         ` Paul Moore
2015-01-20 21:43             ` Guenter Roeck
2015-01-20 17:54     ` Fabio Estevam
2015-01-20 19:00       ` Ross Zwisler
2015-01-20 19:16         ` Fabio Estevam
2015-01-20 19:24           ` Paul Moore
2015-01-20 19:43             ` Fabio Estevam
2015-01-20 20:10               ` Paul Moore

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