Re: __vmalloc with GFP_ATOMIC causes 'sleeping from invalid context'

[Giridhar Pemmasani <giri@lmc.cs.sunysb.edu>]

On Mon, 22 May 2006 11:53:55 +1000, Nick Piggin <nickpiggin@yahoo.com.au> said:

   > Giridhar Pemmasani wrote:
  >> If __vmalloc is called in atomic context with GFP_ATOMIC flags,
  >> __get_vm_area_node is called, which calls kmalloc_node with
  >> GFP_KERNEL flags. This causes 'sleeping function called from
  >> invalid context at mm/slab.c:2729' with 2.6.16-rc4 kernel. A
  >> simple solution is to use

   > I can't see what would cause this in either 2.6.16-rc4 or
   > 2.6.17-rc4.  What is the line?

If someone calls __vmalloc in atomic context (with GFP_ATOMIC flags):

with 2.6.17-rc4, in file mm/vmalloc.c,

__vmalloc calls __vmalloc_node on line 484,
__vmalloc_node calls get_vm_area_node on line 474,
get_vm_area_node calls __get_vm_area_node on line 256,
__get_vm_area_node calls kmalloc_node with GFP_KERNEL on line 180

and in include/linux/slab.h,

kmalloc_node calls kmalloc with GFP_KERNEL on line 164,
kmalloc calls kmem_cache_alloc on line 106,

and in mm/slab.c,

kmem_cache_alloc calls __cache_alloc on line 3136,
__cache_alloc calls cache_alloc_debugcheck_before on line 2880,
cache_alloc_debugcheck_before calls might_sleep_if(GFP_KERNEL & GFP_WAIT)
on line 2783

which causes the warning.

-- 
Giri