Re: [stable] 3.0.0-rc2-git1 -- BUG: sleeping function called from invalid context at mm/slub.c:847

[Greg KH <greg@kroah.com>]

On Wed, Jun 08, 2011 at 03:07:47PM -0700, John Johansen wrote:
> From: John Johansen <john.johansen@canonical.com>
> Date: Wed, 8 Jun 2011 15:03:58 -0700
> Subject: [PATCH] AppArmor: Fix sleep in invalid context from task_setrlimit
> 
> Affected kernels 2.6.36 - 3.0
> 
> AppArmor may do a GFP_KERNEL memory allocation with task_lock(tsk->group_leader);
> held when called from security_task_setrlimit.  This will only occur when the
> task's current policy has been replaced, and the task's creds have not been
> updated before entering the LSM security_task_setrlimit() hook.
> 
> As reported by Miles Lane
> 
> BUG: sleeping function called from invalid context at mm/slub.c:847
>  in_atomic(): 1, irqs_disabled(): 0, pid: 1583, name: cupsd
>  2 locks held by cupsd/1583:
>   #0:  (tasklist_lock){.+.+.+}, at: [<ffffffff8104dafa>] do_prlimit+0x61/0x189
>   #1:  (&(&p->alloc_lock)->rlock){+.+.+.}, at: [<ffffffff8104db2d>]
> do_prlimit+0x94/0x189
>  Pid: 1583, comm: cupsd Not tainted 3.0.0-rc2-git1 #7
>  Call Trace:
>   [<ffffffff8102ebf2>] __might_sleep+0x10d/0x112
>   [<ffffffff810e6f46>] slab_pre_alloc_hook.isra.49+0x2d/0x33
>   [<ffffffff810e7bc4>] kmem_cache_alloc+0x22/0x132
>   [<ffffffff8105b6e6>] prepare_creds+0x35/0xe4
>   [<ffffffff811c0675>] aa_replace_current_profile+0x35/0xb2
>   [<ffffffff811c4d2d>] aa_current_profile+0x45/0x4c
>   [<ffffffff811c4d4d>] apparmor_task_setrlimit+0x19/0x3a
>   [<ffffffff811beaa5>] security_task_setrlimit+0x11/0x13
>   [<ffffffff8104db6b>] do_prlimit+0xd2/0x189
>   [<ffffffff8104dea9>] sys_setrlimit+0x3b/0x48
>   [<ffffffff814062bb>] system_call_fastpath+0x16/0x1b
> 
> Signed-off-by: John Johansen <john.johansen@canonical.com>
> ---
>  security/apparmor/lsm.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>