Memory leak in 2.4 vmalloc.c get_vm_area

Memory leak in 2.4 vmalloc.c get_vm_area

[Nathan Scott]

hi Alan,

I noticed you recently merged this patch with Marcelo in the
2.4 BK tree (lists you as author, and annotation says it came
from DaveM originally)...

        --- 1.10/mm/vmalloc.c   Tue Feb  5 06:10:20 2002
        +++ 1.11/mm/vmalloc.c   Thu Sep  5 05:22:42 2002
        @@ -177,6 +177,8 @@
                if (!area)
                        return NULL;
                size += PAGE_SIZE;
        +       if(!size)
        +               return NULL;
                addr = VMALLOC_START;
                write_lock(&vmlist_lock);
                for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {


This looks to me like it introduces a memory leak in the new !size
case - either the "size" bump and test needs to be moved before the
"area" kmalloc, or we need to kfree(area) before returning NULL.

If you like, I'll make a (trivial) patch to do one of these?

cheers.

-- 
Nathan

Re: Memory leak in 2.4 vmalloc.c get_vm_area

[Dave Jones]

On Tue, Nov 19, 2002 at 10:32:02AM +1100, Nathan Scott wrote:
 > hi Alan,
 > 
 > I noticed you recently merged this patch with Marcelo in the
 > 2.4 BK tree (lists you as author, and annotation says it came
 > from DaveM originally)...
 > 
 >         --- 1.10/mm/vmalloc.c   Tue Feb  5 06:10:20 2002
 >         +++ 1.11/mm/vmalloc.c   Thu Sep  5 05:22:42 2002
 >         @@ -177,6 +177,8 @@
 >                 if (!area)
 >                         return NULL;
 >                 size += PAGE_SIZE;
 >         +       if(!size)
 >         +               return NULL;
 >                 addr = VMALLOC_START;
 >                 write_lock(&vmlist_lock);
 >                 for (p = &vmlist; (tmp = *p) ; p = &tmp->next) {
 > 
 > 
 > This looks to me like it introduces a memory leak in the new !size
 > case - either the "size" bump and test needs to be moved before the
 > "area" kmalloc, or we need to kfree(area) before returning NULL.
 > 
 > If you like, I'll make a (trivial) patch to do one of these?

Correct diagnosis. Patch went to Marcelo a while back.
(Which I thought he took). Alan already picked it up iirc.

Will retransmit, as this is -rc material IMO.

		Dave

-- 
| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs