[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>
diff --git a/arch/mips/kernel/sysirix.c b/arch/mips/kernel/sysirix.c
index 4de1556..7ae4af4 100644
--- a/arch/mips/kernel/sysirix.c
+++ b/arch/mips/kernel/sysirix.c
@@ -581,18 +581,13 @@
}
/*
- * Check if we have enough memory..
+ * Ok, looks good - let it rip.
*/
- if (security_vm_enough_memory((newbrk-oldbrk) >> PAGE_SHIFT)) {
+ if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) {
ret = -ENOMEM;
goto out;
}
-
- /*
- * Ok, looks good - let it rip.
- */
mm->brk = brk;
- do_brk(oldbrk, newbrk-oldbrk);
ret = 0;
out:
