From: "Ram Gupta" The code checks for newbrk with oldbrk which are page aligned before making a check for the memory limit set of data segment. If the memory limit is not page aligned in that case it bypasses the test for the limit if the memory allocation is still for the same page. Signed-off-by: Ram Gupta Signed-off-by: Andrew Morton --- mm/mmap.c | 16 +++++++++++----- 1 files changed, 11 insertions(+), 5 deletions(-) diff -puN mm/mmap.c~mm-fix-bug-in-brk mm/mmap.c --- 25/mm/mmap.c~mm-fix-bug-in-brk Mon Apr 3 16:31:04 2006 +++ 25-akpm/mm/mmap.c Mon Apr 3 16:32:02 2006 @@ -220,6 +220,17 @@ asmlinkage unsigned long sys_brk(unsigne if (brk < mm->end_code) goto out; + + /* + * Check against rlimit here. If this check is done later after the test + * of oldbrk with newbrk then it can escape the test and let the data + * segment grow beyond its set limit the in case where the limit is + * not page aligned -Ram Gupta + */ + rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; + if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) + goto out; + newbrk = PAGE_ALIGN(brk); oldbrk = PAGE_ALIGN(mm->brk); if (oldbrk == newbrk) @@ -232,11 +243,6 @@ asmlinkage unsigned long sys_brk(unsigne goto out; } - /* Check against rlimit.. */ - rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; - if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) - goto out; - /* Check against existing mmap mappings. */ if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE)) goto out; _