From: Hugh Dickins <hugh@veritas.com>
In some cases /proc/<pid>/status shows VmLib: 42949..... kB.
If READ_IMPLIES_EXEC then the break area is VM_EXEC, but omitted from
exec_vm since do_brk contains no __vm_stat_account call. Later munmaps
count its pages out of exec_vm, hence (exec_vm - VmExe) can go negative.
do_brk is right not to call __vm_stat_account, its pages shouldn't need to
be counted. What's wrong is that __vm_stat_account is counting all the
VM_EXEC pages, whereas (to mimic 2.4 and earlier 2.6) it should be leaving
VM_WRITE areas and non-vm_file areas out of exec_vm.
VmLib may still appear larger than before - where a READ_IMPLIES_EXEC
personality makes what was a readonly mapping of a file now executable e.g.
/usr/lib/locale stuff. And a program which mprotects its own text as
writable will appear with wrapped VmLib: sorry, but while it's worth
showing ordinary programs as ordinary, it's not worth much effort to avoid
showing odd ones as odd.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/mmap.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)
diff -puN mm/mmap.c~vmlib-wrapped-executable-brk mm/mmap.c
--- 25/mm/mmap.c~vmlib-wrapped-executable-brk Thu Dec 9 13:07:13 2004
+++ 25-akpm/mm/mmap.c Thu Dec 9 13:07:13 2004
@@ -744,12 +744,12 @@ void __vm_stat_account(struct mm_struct
}
#endif /* CONFIG_HUGETLB */
- if (file)
+ if (file) {
mm->shared_vm += pages;
- else if (flags & stack_flags)
+ if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
+ mm->exec_vm += pages;
+ } else if (flags & stack_flags)
mm->stack_vm += pages;
- if (flags & VM_EXEC)
- mm->exec_vm += pages;
if (flags & (VM_RESERVED|VM_IO))
mm->reserved_vm += pages;
}
_