Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  deal with races in /proc/*/{syscall,stack,personality}
  proc: enable writing to /proc/pid/mem
  proc: make check_mem_permission() return an mm_struct on success
  proc: hold cred_guard_mutex in check_mem_permission()
  proc: disable mem_write after exec
  mm: implement access_remote_vm
  mm: factor out main logic of access_process_vm
  mm: use mm_struct to resolve gate vma's in __get_user_pages
  mm: arch: rename in_gate_area_no_task to in_gate_area_no_mm
  mm: arch: make in_gate_area take an mm_struct instead of a task_struct
  mm: arch: make get_gate_vma take an mm_struct instead of a task_struct
  x86: mark associated mm when running a task in 32 bit compatibility mode
  x86: add context tag to mark mm when running a task in 32-bit compatibility mode
  auxv: require the target to be tracable (or yourself)
  close race in /proc/*/environ
  report errors in /proc/*/*map* sanely
  pagemap: close races with suid execve
  make sessionid permissions in /proc/*/task/* match those in /proc/*
  fix leaks in path_lookupat()

Fix up trivial conflicts in fs/proc/base.c

3 files changed, 57 insertions, 22 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 20d5f7499ce2..51a5c23704af 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1486,9 +1486,9 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                 struct vm_area_struct *vma;
 
                 vma = find_extend_vma(mm, start);
-                if (!vma && in_gate_area(tsk, start)) {
+                if (!vma && in_gate_area(mm, start)) {
                         unsigned long pg = start & PAGE_MASK;
-                        struct vm_area_struct *gate_vma = get_gate_vma(tsk);
+                        struct vm_area_struct *gate_vma = get_gate_vma(mm);
                         pgd_t *pgd;
                         pud_t *pud;
                         pmd_t *pmd;
@@ -1591,10 +1591,13 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                                 return i ? i : -EFAULT;
                                         BUG();
                                 }
-                                if (ret & VM_FAULT_MAJOR)
-                                        tsk->maj_flt++;
-                                else
-                                        tsk->min_flt++;
+
+                                if (tsk) {
+                                        if (ret & VM_FAULT_MAJOR)
+                                                tsk->maj_flt++;
+                                        else
+                                                tsk->min_flt++;
+                                }
 
                                 if (ret & VM_FAULT_RETRY) {
                                         if (nonblocking)
@@ -1641,7 +1644,8 @@ EXPORT_SYMBOL(__get_user_pages);
 
 /**
  * get_user_pages() - pin user pages in memory
- * @tsk:        task_struct of target task
+ * @tsk:        the task_struct to use for page fault accounting, or
+ *              NULL if faults are not to be recorded.
  * @mm:         mm_struct of target mm
  * @start:      starting user address
  * @nr_pages:   number of pages from start to pin
@@ -3499,7 +3503,7 @@ static int __init gate_vma_init(void)
 __initcall(gate_vma_init);
 #endif
 
-struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
 {
 #ifdef AT_SYSINFO_EHDR
         return &gate_vma;
@@ -3508,7 +3512,7 @@ struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
 #endif
 }
 
-int in_gate_area_no_task(unsigned long addr)
+int in_gate_area_no_mm(unsigned long addr)
 {
 #ifdef AT_SYSINFO_EHDR
         if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
@@ -3649,20 +3653,15 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
 #endif
 
 /*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
+ * Access another process' address space as given in mm.  If non-NULL, use the
+ * given task for page fault accounting.
  */
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
+                unsigned long addr, void *buf, int len, int write)
 {
-        struct mm_struct *mm;
         struct vm_area_struct *vma;
         void *old_buf = buf;
 
-        mm = get_task_mm(tsk);
-        if (!mm)
-                return 0;
-
         down_read(&mm->mmap_sem);
         /* ignore errors, just check how much was successfully transferred */
         while (len) {
@@ -3711,11 +3710,47 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
                 addr += bytes;
         }
         up_read(&mm->mmap_sem);
-        mmput(mm);
 
         return buf - old_buf;
 }
 
+/**
+ * @access_remote_vm - access another process' address space
+ * @mm:         the mm_struct of the target address space
+ * @addr:       start address to access
+ * @buf:        source or destination buffer
+ * @len:        number of bytes to transfer
+ * @write:      whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+                void *buf, int len, int write)
+{
+        return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
+/*
+ * Access another process' address space.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr,
+                void *buf, int len, int write)
+{
+        struct mm_struct *mm;
+        int ret;
+
+        mm = get_task_mm(tsk);
+        if (!mm)
+                return 0;
+
+        ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
+        mmput(mm);
+
+        return ret;
+}
+
 /*
  * Print the name of a VMA.
  */
diff --git a/mm/mlock.c b/mm/mlock.c
index c3924c7f00be..2689a08c79af 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -237,7 +237,7 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
 
         if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) ||
                         is_vm_hugetlb_page(vma) ||
-                        vma == get_gate_vma(current))) {
+                        vma == get_gate_vma(current->mm))) {
 
                 __mlock_vma_pages_range(vma, start, end, NULL);
 
@@ -332,7 +332,7 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
         int lock = newflags & VM_LOCKED;
 
         if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) ||
-            is_vm_hugetlb_page(vma) || vma == get_gate_vma(current))
+            is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))
                 goto out;       /* don't set VM_LOCKED,  don't count */
 
         pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
diff --git a/mm/nommu.c b/mm/nommu.c
index f59e1424d3db..e629143f9440 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1963,7 +1963,7 @@ error:
         return -ENOMEM;
 }
 
-int in_gate_area_no_task(unsigned long addr)
+int in_gate_area_no_mm(unsigned long addr)
 {
         return 0;
 }