There are no mutex protection for the dev->map_hash while calling
the drm_ht_find_item in the function drm_do_vm_fault. So try to
mutex firstly and then find the list for using to avoid this race
condition.
Signed-off-by: Chen Jun <jun.d.chen@xxxxxxxxx>
---
drivers/gpu/drm/drm_vm.c | 11 +++++++++--
1 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_vm.c b/drivers/gpu/drm/drm_vm.c
index b5c5af7..1d95221 100644
--- a/drivers/gpu/drm/drm_vm.c
+++ b/drivers/gpu/drm/drm_vm.c
@@ -107,8 +107,11 @@ static int drm_do_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
if (!dev->agp || !dev->agp->cant_use_aperture)
goto vm_fault_error;
- if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff, &hash))
+ mutex_lock(&dev->struct_mutex);
+ if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff, &hash)) {
+ mutex_unlock(&dev->struct_mutex);
goto vm_fault_error;
+ }
r_list = drm_hash_entry(hash, struct drm_map_list, hash);
map = r_list->map;
@@ -140,8 +143,10 @@ static int drm_do_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
break;
}
- if (&agpmem->head == &dev->agp->memory)
+ if (&agpmem->head == &dev->agp->memory) {
+ mutex_unlock(&dev->struct_mutex);
goto vm_fault_error;
+ }
/*
* Get the page, inc the use count, and return it
@@ -151,6 +156,7 @@ static int drm_do_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
get_page(page);
vmf->page = page;
+ mutex_unlock(&dev->struct_mutex);
DRM_DEBUG
("baddr = 0x%llx page = 0x%p, offset = 0x%llx, count=%d\n",
(unsigned long long)baddr,
@@ -159,6 +165,7 @@ static int drm_do_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
page_count(page));
return 0;
}
+ mutex_unlock(&dev->struct_mutex);
vm_fault_error:
return VM_FAULT_SIGBUS; /* Disallow mremap */
}
--
1.7.4.1
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