Re: [PATCH bpf-next v3 2/7] bpf: add two kfunc for TRACE_SESSION

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

Hi Menglong,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Menglong-Dong/bpf-add-tracing-session-support/20251026-110720
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20251026030143.23807-3-dongml2%40chinatelecom.cn
patch subject: [PATCH bpf-next v3 2/7] bpf: add two kfunc for TRACE_SESSION
config: i386-randconfig-061-20251027 (https://download.01.org/0day-ci/archive/20251027/202510270955.mbxODFvZ-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251027/202510270955.mbxODFvZ-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/202510270955.mbxODFvZ-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
   kernel/trace/bpf_trace.c:833:41: sparse: sparse: incorrect type in assignment (different address spaces) @@     expected void [noderef] __user *[addressable] [assigned] [usertype] sival_ptr @@     got void * @@
   kernel/trace/bpf_trace.c:833:41: sparse:     expected void [noderef] __user *[addressable] [assigned] [usertype] sival_ptr
   kernel/trace/bpf_trace.c:833:41: sparse:     got void *
   kernel/trace/bpf_trace.c:3573:52: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c:3587:56: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c:3601:52: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c:3608:56: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c:3616:52: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c:3624:56: sparse: sparse: cast removes address space '__user' of expression
   kernel/trace/bpf_trace.c: note: in included file (through include/linux/rbtree.h, include/linux/mm_types.h, include/linux/mmzone.h, ...):
   include/linux/rcupdate.h:895:9: sparse: sparse: context imbalance in 'uprobe_prog_run' - unexpected unlock
>> kernel/trace/bpf_trace.c:3379:35: sparse: sparse: non size-preserving integer to pointer cast

vim +3379 kernel/trace/bpf_trace.c

  3372	
  3373	__bpf_kfunc u64 *bpf_fsession_cookie(void *ctx)
  3374	{
  3375		/* This helper call is inlined by verifier. */
  3376		u64 nr_args = ((u64 *)ctx)[-1];
  3377	
  3378		/* ctx[nr_args + 2] is the session cookie address */
> 3379		return (u64 *)((u64 *)ctx)[nr_args + 2];
  3380	}
  3381	

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