From: David Woodhouse Bad things can happen if a 32-bit process is the last user of a 64-bit mm. TASK_SIZE isn't a constant, and we can end up clearing page tables only up to the 32-bit TASK_SIZE instead of all the way. We should probably double-check every instance of TASK_SIZE or USER_PTRS_PER_PGD for this kind of problem. We should also double-check that MM_VM_SIZE() and other such things are correctly defined on all architectures. I already fixed ppc64 which let it stay as TASK_SIZE, and hence dependent on the _current_ context instead of the mm in the argument. Signed-off-by: Andrew Morton --- 25-akpm/mm/mmap.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff -puN mm/mmap.c~task_size-is-variable mm/mmap.c --- 25/mm/mmap.c~task_size-is-variable 2005-01-25 22:08:40.903785456 -0800 +++ 25-akpm/mm/mmap.c 2005-01-25 22:08:40.908784696 -0800 @@ -1612,8 +1612,8 @@ static void free_pgtables(struct mmu_gat unsigned long last = end + PGDIR_SIZE - 1; struct mm_struct *mm = tlb->mm; - if (last > TASK_SIZE || last < end) - last = TASK_SIZE; + if (last > MM_VM_SIZE(mm) || last < end) + last = MM_VM_SIZE(mm); if (!prev) { prev = mm->mmap; _