drivers/gpu/drm/radeon/radeon_kms.c:672:7: warning: variable 'vm' is used uninitialized whenever 'if' condition is false

From: kernel test robot
Date: Tue Nov 30 2021 - 15:31:36 EST

tree: https://github.com/0day-ci/linux/commits/UPDATE-20211130-233655/Zhou-Qingyang/drm-radeon-radeon_kms-Fix-a-NULL-pointer-dereference-in-radeon_driver_open_kms/20211130-231509
head: 123fb3d217e89c4388fdb08b63991bac7c324219
commit: 123fb3d217e89c4388fdb08b63991bac7c324219 drm/radeon/radeon_kms: Fix a NULL pointer dereference in radeon_driver_open_kms()
date: 5 hours ago
config: mips-randconfig-r014-20211128 (https://download.01.org/0day-ci/archive/20211201/202112010420.xkXHciHS-lkp@xxxxxxxxx/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 25eb7fa01d7ebbe67648ea03841cda55b4239ab2)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install mips cross compiling tool for clang build
# apt-get install binutils-mips-linux-gnu
# https://github.com/0day-ci/linux/commit/123fb3d217e89c4388fdb08b63991bac7c324219
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review UPDATE-20211130-233655/Zhou-Qingyang/drm-radeon-radeon_kms-Fix-a-NULL-pointer-dereference-in-radeon_driver_open_kms/20211130-231509
git checkout 123fb3d217e89c4388fdb08b63991bac7c324219
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash drivers/gpu/drm/radeon/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> drivers/gpu/drm/radeon/radeon_kms.c:672:7: warning: variable 'vm' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (rdev->accel_working) {
^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/radeon_kms.c:705:23: note: uninitialized use occurs here
radeon_vm_fini(rdev, vm);
^~
drivers/gpu/drm/radeon/radeon_kms.c:672:3: note: remove the 'if' if its condition is always true
if (rdev->accel_working) {
^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/radeon_kms.c:664:6: warning: variable 'vm' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (rdev->family >= CHIP_CAYMAN) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/radeon_kms.c:705:23: note: uninitialized use occurs here
radeon_vm_fini(rdev, vm);
^~
drivers/gpu/drm/radeon/radeon_kms.c:664:2: note: remove the 'if' if its condition is always true
if (rdev->family >= CHIP_CAYMAN) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/radeon_kms.c:653:22: note: initialize the variable 'vm' to silence this warning
struct radeon_vm *vm;
^
= NULL
2 warnings generated.


vim +672 drivers/gpu/drm/radeon/radeon_kms.c

771fe6b912fca54 Jerome Glisse 2009-06-05 638
f482a1419545ded Alex Deucher 2012-07-17 639 /**
f482a1419545ded Alex Deucher 2012-07-17 640 * radeon_driver_open_kms - drm callback for open
f482a1419545ded Alex Deucher 2012-07-17 641 *
f482a1419545ded Alex Deucher 2012-07-17 642 * @dev: drm dev pointer
f482a1419545ded Alex Deucher 2012-07-17 643 * @file_priv: drm file
f482a1419545ded Alex Deucher 2012-07-17 644 *
f482a1419545ded Alex Deucher 2012-07-17 645 * On device open, init vm on cayman+ (all asics).
f482a1419545ded Alex Deucher 2012-07-17 646 * Returns 0 on success, error on failure.
f482a1419545ded Alex Deucher 2012-07-17 647 */
771fe6b912fca54 Jerome Glisse 2009-06-05 648 int radeon_driver_open_kms(struct drm_device *dev, struct drm_file *file_priv)
771fe6b912fca54 Jerome Glisse 2009-06-05 649 {
721604a15b934f0 Jerome Glisse 2012-01-05 650 struct radeon_device *rdev = dev->dev_private;
10ebc0bc09344ab Dave Airlie 2012-09-17 651 int r;
123fb3d217e89c4 Zhou Qingyang 2021-11-30 652 struct radeon_fpriv *fpriv;
123fb3d217e89c4 Zhou Qingyang 2021-11-30 653 struct radeon_vm *vm;
721604a15b934f0 Jerome Glisse 2012-01-05 654
721604a15b934f0 Jerome Glisse 2012-01-05 655 file_priv->driver_priv = NULL;
721604a15b934f0 Jerome Glisse 2012-01-05 656
10ebc0bc09344ab Dave Airlie 2012-09-17 657 r = pm_runtime_get_sync(dev->dev);
9fb10671011143d Aditya Pakki 2020-06-13 658 if (r < 0) {
9fb10671011143d Aditya Pakki 2020-06-13 659 pm_runtime_put_autosuspend(dev->dev);
10ebc0bc09344ab Dave Airlie 2012-09-17 660 return r;
9fb10671011143d Aditya Pakki 2020-06-13 661 }
10ebc0bc09344ab Dave Airlie 2012-09-17 662
721604a15b934f0 Jerome Glisse 2012-01-05 663 /* new gpu have virtual address space support */
721604a15b934f0 Jerome Glisse 2012-01-05 664 if (rdev->family >= CHIP_CAYMAN) {
721604a15b934f0 Jerome Glisse 2012-01-05 665
721604a15b934f0 Jerome Glisse 2012-01-05 666 fpriv = kzalloc(sizeof(*fpriv), GFP_KERNEL);
721604a15b934f0 Jerome Glisse 2012-01-05 667 if (unlikely(!fpriv)) {
32c59dc14b72803 Alex Deucher 2016-08-31 668 r = -ENOMEM;
32c59dc14b72803 Alex Deucher 2016-08-31 669 goto out_suspend;
721604a15b934f0 Jerome Glisse 2012-01-05 670 }
721604a15b934f0 Jerome Glisse 2012-01-05 671
544143f9e01a60a Alex Deucher 2015-01-28 @672 if (rdev->accel_working) {
cc9e67e3d7000c1 Christian König 2014-07-18 673 vm = &fpriv->vm;
cc9e67e3d7000c1 Christian König 2014-07-18 674 r = radeon_vm_init(rdev, vm);
74073c9dd299056 Quentin Casasnovas 2014-03-18 675 if (r) {
123fb3d217e89c4 Zhou Qingyang 2021-11-30 676 goto out_fpriv;
74073c9dd299056 Quentin Casasnovas 2014-03-18 677 }
d72d43cfc5847c1 Christian König 2012-10-09 678
f1e3dc708aaadb9 Christian König 2014-02-20 679 r = radeon_bo_reserve(rdev->ring_tmp_bo.bo, false);
74073c9dd299056 Quentin Casasnovas 2014-03-18 680 if (r) {
123fb3d217e89c4 Zhou Qingyang 2021-11-30 681 goto out_vm_fini;
74073c9dd299056 Quentin Casasnovas 2014-03-18 682 }
f1e3dc708aaadb9 Christian König 2014-02-20 683
d72d43cfc5847c1 Christian König 2012-10-09 684 /* map the ib pool buffer read only into
d72d43cfc5847c1 Christian König 2012-10-09 685 * virtual address space */
cc9e67e3d7000c1 Christian König 2014-07-18 686 vm->ib_bo_va = radeon_vm_bo_add(rdev, vm,
d72d43cfc5847c1 Christian König 2012-10-09 687 rdev->ring_tmp_bo.bo);
123fb3d217e89c4 Zhou Qingyang 2021-11-30 688 if (!vm->ib_bo_va) {
123fb3d217e89c4 Zhou Qingyang 2021-11-30 689 r = -ENOMEM;
123fb3d217e89c4 Zhou Qingyang 2021-11-30 690 goto out_vm_fini;
123fb3d217e89c4 Zhou Qingyang 2021-11-30 691 }
123fb3d217e89c4 Zhou Qingyang 2021-11-30 692
cc9e67e3d7000c1 Christian König 2014-07-18 693 r = radeon_vm_bo_set_addr(rdev, vm->ib_bo_va,
cc9e67e3d7000c1 Christian König 2014-07-18 694 RADEON_VA_IB_OFFSET,
d72d43cfc5847c1 Christian König 2012-10-09 695 RADEON_VM_PAGE_READABLE |
d72d43cfc5847c1 Christian König 2012-10-09 696 RADEON_VM_PAGE_SNOOPED);
721604a15b934f0 Jerome Glisse 2012-01-05 697 if (r) {
123fb3d217e89c4 Zhou Qingyang 2021-11-30 698 goto out_vm_fini;
721604a15b934f0 Jerome Glisse 2012-01-05 699 }
24f47acc78b0ab5 Jérôme Glisse 2014-05-07 700 }
721604a15b934f0 Jerome Glisse 2012-01-05 701 file_priv->driver_priv = fpriv;
721604a15b934f0 Jerome Glisse 2012-01-05 702 }
10ebc0bc09344ab Dave Airlie 2012-09-17 703
123fb3d217e89c4 Zhou Qingyang 2021-11-30 704 out_vm_fini:
123fb3d217e89c4 Zhou Qingyang 2021-11-30 705 radeon_vm_fini(rdev, vm);
123fb3d217e89c4 Zhou Qingyang 2021-11-30 706 out_fpriv:
123fb3d217e89c4 Zhou Qingyang 2021-11-30 707 kfree(fpriv);
32c59dc14b72803 Alex Deucher 2016-08-31 708 out_suspend:
10ebc0bc09344ab Dave Airlie 2012-09-17 709 pm_runtime_mark_last_busy(dev->dev);
10ebc0bc09344ab Dave Airlie 2012-09-17 710 pm_runtime_put_autosuspend(dev->dev);
32c59dc14b72803 Alex Deucher 2016-08-31 711 return r;
771fe6b912fca54 Jerome Glisse 2009-06-05 712 }
771fe6b912fca54 Jerome Glisse 2009-06-05 713

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