mm/mmap.c: use pr_emerg when printing BUG related information

[karo-tx-linux.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index 64c9d736155c7a546e6d133426a0861a63688ead..c0a3637cdb645b0eed66c18edcd10431bfd5417b 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -221,7 +221,7 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
        if (vma->vm_flags & VM_DENYWRITE)
                atomic_inc(&file_inode(file)->i_writecount);
        if (vma->vm_flags & VM_SHARED)
-               mapping->i_mmap_writable--;
+               mapping_unmap_writable(mapping);
 
        flush_dcache_mmap_lock(mapping);
        if (unlikely(vma->vm_flags & VM_NONLINEAR))
@@ -369,20 +369,20 @@ static int browse_rb(struct rb_root *root)
                struct vm_area_struct *vma;
                vma = rb_entry(nd, struct vm_area_struct, vm_rb);
                if (vma->vm_start < prev) {
-                       pr_info("vm_start %lx prev %lx\n", vma->vm_start, prev);
+                       pr_emerg("vm_start %lx prev %lx\n", vma->vm_start, prev);
                        bug = 1;
                }
                if (vma->vm_start < pend) {
-                       pr_info("vm_start %lx pend %lx\n", vma->vm_start, pend);
+                       pr_emerg("vm_start %lx pend %lx\n", vma->vm_start, pend);
                        bug = 1;
                }
                if (vma->vm_start > vma->vm_end) {
-                       pr_info("vm_end %lx < vm_start %lx\n",
+                       pr_emerg("vm_end %lx < vm_start %lx\n",
                                vma->vm_end, vma->vm_start);
                        bug = 1;
                }
                if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) {
-                       pr_info("free gap %lx, correct %lx\n",
+                       pr_emerg("free gap %lx, correct %lx\n",
                               vma->rb_subtree_gap,
                               vma_compute_subtree_gap(vma));
                        bug = 1;
@@ -396,7 +396,7 @@ static int browse_rb(struct rb_root *root)
        for (nd = pn; nd; nd = rb_prev(nd))
                j++;
        if (i != j) {
-               pr_info("backwards %d, forwards %d\n", j, i);
+               pr_emerg("backwards %d, forwards %d\n", j, i);
                bug = 1;
        }
        return bug ? -1 : i;
@@ -431,17 +431,17 @@ static void validate_mm(struct mm_struct *mm)
                i++;
        }
        if (i != mm->map_count) {
-               pr_info("map_count %d vm_next %d\n", mm->map_count, i);
+               pr_emerg("map_count %d vm_next %d\n", mm->map_count, i);
                bug = 1;
        }
        if (highest_address != mm->highest_vm_end) {
-               pr_info("mm->highest_vm_end %lx, found %lx\n",
+               pr_emerg("mm->highest_vm_end %lx, found %lx\n",
                       mm->highest_vm_end, highest_address);
                bug = 1;
        }
        i = browse_rb(&mm->mm_rb);
        if (i != mm->map_count) {
-               pr_info("map_count %d rb %d\n", mm->map_count, i);
+               pr_emerg("map_count %d rb %d\n", mm->map_count, i);
                bug = 1;
        }
        BUG_ON(bug);
@@ -622,7 +622,7 @@ static void __vma_link_file(struct vm_area_struct *vma)
                if (vma->vm_flags & VM_DENYWRITE)
                        atomic_dec(&file_inode(file)->i_writecount);
                if (vma->vm_flags & VM_SHARED)
-                       mapping->i_mmap_writable++;
+                       atomic_inc(&mapping->i_mmap_writable);
 
                flush_dcache_mmap_lock(mapping);
                if (unlikely(vma->vm_flags & VM_NONLINEAR))
@@ -1577,6 +1577,17 @@ munmap_back:
                        if (error)
                                goto free_vma;
                }
+               if (vm_flags & VM_SHARED) {
+                       error = mapping_map_writable(file->f_mapping);
+                       if (error)
+                               goto allow_write_and_free_vma;
+               }
+
+               /* ->mmap() can change vma->vm_file, but must guarantee that
+                * vma_link() below can deny write-access if VM_DENYWRITE is set
+                * and map writably if VM_SHARED is set. This usually means the
+                * new file must not have been exposed to user-space, yet.
+                */
                vma->vm_file = get_file(file);
                error = file->f_op->mmap(file, vma);
                if (error)
@@ -1616,8 +1627,12 @@ munmap_back:
 
        vma_link(mm, vma, prev, rb_link, rb_parent);
        /* Once vma denies write, undo our temporary denial count */
-       if (vm_flags & VM_DENYWRITE)
-               allow_write_access(file);
+       if (file) {
+               if (vm_flags & VM_SHARED)
+                       mapping_unmap_writable(file->f_mapping);
+               if (vm_flags & VM_DENYWRITE)
+                       allow_write_access(file);
+       }
        file = vma->vm_file;
 out:
        perf_event_mmap(vma);
@@ -1646,14 +1661,17 @@ out:
        return addr;
 
 unmap_and_free_vma:
-       if (vm_flags & VM_DENYWRITE)
-               allow_write_access(file);
        vma->vm_file = NULL;
        fput(file);
 
        /* Undo any partial mapping done by a device driver. */
        unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
        charged = 0;
+       if (vm_flags & VM_SHARED)
+               mapping_unmap_writable(file->f_mapping);
+allow_write_and_free_vma:
+       if (vm_flags & VM_DENYWRITE)
+               allow_write_access(file);
 free_vma:
        kmem_cache_free(vm_area_cachep, vma);
 unacct_error: