Re: [RFC PATCH] drm/sched: Fix a UAF on drm_sched_fence::sched

[kernel test robot <lkp@intel.com>]

Hi Boris,

[This is a private test report for your RFC patch.]
kernel test robot noticed the following build errors:

[auto build test ERROR on drm/drm-next]
[also build test ERROR on drm-exynos/exynos-drm-next drm-intel/for-linux-next drm-intel/for-linux-next-fixes drm-misc/drm-misc-next drm-tip/drm-tip linus/master v6.11-rc6 next-20240830]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Boris-Brezillon/drm-sched-Fix-a-UAF-on-drm_sched_fence-sched/20240830-012038
base:   git://anongit.freedesktop.org/drm/drm drm-next
patch link:    https://lore.kernel.org/r/20240829171238.609481-1-boris.brezillon%40collabora.com
patch subject: [RFC PATCH] drm/sched: Fix a UAF on drm_sched_fence::sched
config: i386-buildonly-randconfig-003-20240902 (https://download.01.org/0day-ci/archive/20240902/202409020603.tc9e1ATi-lkp@intel.com/config)
compiler: clang version 18.1.5 (https://github.com/llvm/llvm-project 617a15a9eac96088ae5e9134248d8236e34b91b1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240902/202409020603.tc9e1ATi-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409020603.tc9e1ATi-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from drivers/gpu/drm/lima/lima_dlbu.c:7:
   In file included from drivers/gpu/drm/lima/lima_device.h:12:
   In file included from drivers/gpu/drm/lima/lima_sched.h:7:
>> include/drm/gpu_scheduler.h:290:2: error: call to undeclared function 'kfree'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     290 |         kfree(tl->name);
         |         ^
   1 error generated.
--
   In file included from drivers/gpu/drm/lima/lima_trace.c:4:
   In file included from drivers/gpu/drm/lima/lima_sched.h:7:
>> include/drm/gpu_scheduler.h:290:2: error: call to undeclared function 'kfree'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
     290 |         kfree(tl->name);
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:33:
   include/linux/slab.h:278:6: error: conflicting types for 'kfree'
     278 | void kfree(const void *objp);
         |      ^
   include/drm/gpu_scheduler.h:290:2: note: previous implicit declaration is here
     290 |         kfree(tl->name);
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:1127:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:98:11: warning: array index 3 is past the end of the array (that has type 'unsigned long[2]') [-Warray-bounds]
      98 |                 return (set->sig[3] | set->sig[2] |
         |                         ^        ~
   arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
      24 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:1127:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:98:25: warning: array index 2 is past the end of the array (that has type 'unsigned long[2]') [-Warray-bounds]
      98 |                 return (set->sig[3] | set->sig[2] |
         |                                       ^        ~
   arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
      24 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:1127:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:11: warning: array index 3 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     114 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                          ^         ~
   arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
      24 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:1127:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:27: warning: array index 3 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]
     114 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                                          ^         ~
   arch/x86/include/asm/signal.h:24:2: note: array 'sig' declared here
      24 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from drivers/gpu/drm/lima/lima_trace.c:7:
   In file included from drivers/gpu/drm/lima/lima_trace.h:50:
   In file included from include/trace/define_trace.h:102:
   In file included from include/trace/trace_events.h:21:
   In file included from include/linux/trace_events.h:6:
   In file included from include/linux/ring_buffer.h:5:
   In file included from include/linux/mm.h:1127:
   In file included from include/linux/huge_mm.h:8:
   In file included from include/linux/fs.h:33:
   In file included from include/linux/percpu-rwsem.h:7:
   In file included from include/linux/rcuwait.h:6:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:115:5: warning: array index 2 is past the end of the array (that has type 'const unsigned long[2]') [-Warray-bounds]


vim +/kfree +290 include/drm/gpu_scheduler.h

   283	
   284	static inline void
   285	drm_sched_fence_timeline_release(struct kref *kref)
   286	{
   287		struct drm_sched_fence_timeline *tl =
   288			container_of(kref, struct drm_sched_fence_timeline, kref);
   289	
 > 290		kfree(tl->name);
   291		kfree(tl);
   292	}
   293	

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