shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 10:31:46 +09:00
Code Issues Packages Projects Releases Wiki Activity

drm/i915: Avoid potential vm use-after-free

Browse Source 
commit 41d419382e upstream.

Adding the vm to the vm_xa table makes it visible to userspace, which
could try to race with us to close the vm.  So we need to take our extra
reference before putting it in the table.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Fixes: 9ec8795e7d ("drm/i915: Drop __rcu from gem_context->vm")
Cc: <stable@vger.kernel.org> # v5.16+
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230119173321.2825472-1-robdclark@gmail.com
(cherry picked from commit 99343c46d4)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Rob Clark
2023-01-19 09:32:58 -08:00
committed by Greg Kroah-Hartman
parent 52c6d3a84a
commit 764accc2c1
1 changed files with 12 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/gpu/drm/i915/gem/i915_gem_context.c
View File

@@ -1861,12 +1861,20 @@ static int get_ppgtt(struct drm_i915_file_private *file_priv,
vm = ctx->vm;
GEM_BUG_ON(!vm);
err = xa_alloc(&file_priv->vm_xa, &id, vm, xa_limit_32b, GFP_KERNEL);
if (err)
return err;
/*
* Get a reference for the allocated handle. Once the handle is
* visible in the vm_xa table, userspace could try to close it
* from under our feet, so we need to hold the extra reference
* first.
*/
i915_vm_get(vm);
err = xa_alloc(&file_priv->vm_xa, &id, vm, xa_limit_32b, GFP_KERNEL);
if (err) {
i915_vm_put(vm);
return err;
}
GEM_BUG_ON(id == 0); /* reserved for invalid/unassigned ppgtt */
args->value = id;
args->size = 0;