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authorHugh Dickins <hugh@veritas.com>2005-09-14 06:13:02 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-14 11:18:13 -0700
commit2fd4ef85e0db9ed75c98e13953257a967ea55e03 (patch)
tree119dfe9f88a832f3db6ff66e631112626f268f18 /mm/mmap.c
parentfb085cf1d4294824571815d487daccc0609543f0 (diff)
downloadlwn-2fd4ef85e0db9ed75c98e13953257a967ea55e03.tar.gz
lwn-2fd4ef85e0db9ed75c98e13953257a967ea55e03.zip
[PATCH] error path in setup_arg_pages() misses vm_unacct_memory()
Pavel Emelianov and Kirill Korotaev observe that fs and arch users of security_vm_enough_memory tend to forget to vm_unacct_memory when a failure occurs further down (typically in setup_arg_pages variants). These are all users of insert_vm_struct, and that reservation will only be unaccounted on exit if the vma is marked VM_ACCOUNT: which in some cases it is (hidden inside VM_STACK_FLAGS) and in some cases it isn't. So x86_64 32-bit and ppc64 vDSO ELFs have been leaking memory into Committed_AS each time they're run. But don't add VM_ACCOUNT to them, it's inappropriate to reserve against the very unlikely case that gdb be used to COW a vDSO page - we ought to do something about that in do_wp_page, but there are yet other inconsistencies to be resolved. The safe and economical way to fix this is to let insert_vm_struct do the security_vm_enough_memory check when it finds VM_ACCOUNT is set. And the MIPS irix_brk has been calling security_vm_enough_memory before calling do_brk which repeats it, doubly accounting and so also leaking. Remove that, and all the fs and arch calls to security_vm_enough_memory: give it a less misleading name later on. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-Off-By: Kirill Korotaev <dev@sw.ru> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 12334aecf8ad..8b8e05f07cdb 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1993,6 +1993,9 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
__vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
if (__vma && __vma->vm_start < vma->vm_end)
return -ENOMEM;
+ if ((vma->vm_flags & VM_ACCOUNT) &&
+ security_vm_enough_memory(vma_pages(vma)))
+ return -ENOMEM;
vma_link(mm, vma, prev, rb_link, rb_parent);
return 0;
}