diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/ptrace.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 410f9de937bc..f6912dd7953e 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -28,6 +28,7 @@ static int access_one_page(struct mm_struct * mm, struct vm_area_struct * vma, u struct page *page; repeat: + spin_lock(&mm->page_table_lock); pgdir = pgd_offset(vma->vm_mm, addr); if (pgd_none(*pgdir)) goto fault_in_page; @@ -47,9 +48,13 @@ repeat: /* ZERO_PAGE is special: reads from it are ok even though it's marked reserved */ if (page != ZERO_PAGE(addr) || write) { - if ((!VALID_PAGE(page)) || PageReserved(page)) + if ((!VALID_PAGE(page)) || PageReserved(page)) { + spin_unlock(&mm->page_table_lock); return 0; + } } + get_page(page); + spin_unlock(&mm->page_table_lock); flush_cache_page(vma, addr); if (write) { @@ -64,19 +69,23 @@ repeat: flush_page_to_ram(page); kunmap(page); } + put_page(page); return len; fault_in_page: + spin_unlock(&mm->page_table_lock); /* -1: out of memory. 0 - unmapped page */ if (handle_mm_fault(mm, vma, addr, write) > 0) goto repeat; return 0; bad_pgd: + spin_unlock(&mm->page_table_lock); pgd_ERROR(*pgdir); return 0; bad_pmd: + spin_unlock(&mm->page_table_lock); pmd_ERROR(*pgmiddle); return 0; } |