Re: [PATCH stable linux-5.10.y v1 2/8] bpf: Replace ARG_XXX_OR_NULL with ARG_XXX | PTR_MAYBE_NULL

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

✅ All tests passed successfully. No issues detected.
No action required from the submitter.

The upstream commit SHA1 provided is correct: 48946bd6a5d695c50b34546864b79c1f910a33c1

WARNING: Author mismatch between patch and upstream commit:
Backport author: Puranjay Mohan<puranjay@kernel.org>
Commit author: Hao Luo<haoluo@google.com>

Status in newer kernel trees:
6.15.y | Present (exact SHA1)
6.14.y | Present (exact SHA1)
6.12.y | Present (exact SHA1)
6.6.y | Present (exact SHA1)
6.1.y | Present (exact SHA1)
5.15.y | Present (different SHA1: d58a396fa6c9)

Note: The patch differs from the upstream commit:
---
1:  48946bd6a5d69 ! 1:  4b4f340273f41 bpf: Replace ARG_XXX_OR_NULL with ARG_XXX | PTR_MAYBE_NULL
    @@ Metadata
      ## Commit message ##
         bpf: Replace ARG_XXX_OR_NULL with ARG_XXX | PTR_MAYBE_NULL
     
    +    commit 48946bd6a5d695c50b34546864b79c1f910a33c1 upstream.
    +
         We have introduced a new type to make bpf_arg composable, by
         reserving high bits of bpf_arg to represent flags of a type.
     
    @@ Commit message
     
         Signed-off-by: Hao Luo <haoluo@google.com>
         Signed-off-by: Alexei Starovoitov <ast@kernel.org>
    +    Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
         Link: https://lore.kernel.org/bpf/20211217003152.48334-3-haoluo@google.com
    +    Cc: stable@vger.kernel.org # 5.10.x
     
      ## include/linux/bpf.h ##
     @@ include/linux/bpf.h: enum bpf_arg_type {
    @@ include/linux/bpf.h: enum bpf_arg_type {
      	ARG_CONST_ALLOC_SIZE_OR_ZERO,	/* number of allocated bytes requested */
      	ARG_PTR_TO_BTF_ID_SOCK_COMMON,	/* pointer to in-kernel sock_common or bpf-mirrored bpf_sock */
      	ARG_PTR_TO_PERCPU_BTF_ID,	/* pointer to in-kernel percpu type */
    - 	ARG_PTR_TO_FUNC,	/* pointer to a bpf program function */
    --	ARG_PTR_TO_STACK_OR_NULL,	/* pointer to stack or NULL */
    -+	ARG_PTR_TO_STACK,	/* pointer to stack */
    - 	ARG_PTR_TO_CONST_STR,	/* pointer to a null terminated read-only string */
    - 	ARG_PTR_TO_TIMER,	/* pointer to bpf_timer */
      	__BPF_ARG_TYPE_MAX,
      
     +	/* Extended arg_types. */
    @@ include/linux/bpf.h: enum bpf_arg_type {
     +	ARG_PTR_TO_CTX_OR_NULL		= PTR_MAYBE_NULL | ARG_PTR_TO_CTX,
     +	ARG_PTR_TO_SOCKET_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_SOCKET,
     +	ARG_PTR_TO_ALLOC_MEM_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_ALLOC_MEM,
    -+	ARG_PTR_TO_STACK_OR_NULL	= PTR_MAYBE_NULL | ARG_PTR_TO_STACK,
     +
      	/* This must be the last entry. Its purpose is to ensure the enum is
      	 * wide enough to hold the higher bits reserved for bpf_type_flag.
    @@ kernel/bpf/verifier.c: static bool arg_type_may_be_refcounted(enum bpf_arg_type
     -	       type == ARG_PTR_TO_MEM_OR_NULL ||
     -	       type == ARG_PTR_TO_CTX_OR_NULL ||
     -	       type == ARG_PTR_TO_SOCKET_OR_NULL ||
    --	       type == ARG_PTR_TO_ALLOC_MEM_OR_NULL ||
    --	       type == ARG_PTR_TO_STACK_OR_NULL;
    +-	       type == ARG_PTR_TO_ALLOC_MEM_OR_NULL;
     +	return type & PTR_MAYBE_NULL;
      }
      
      /* Determine whether the function releases some resources allocated by another
    -@@ kernel/bpf/verifier.c: static int process_timer_func(struct bpf_verifier_env *env, int regno,
    +@@ kernel/bpf/verifier.c: static int process_spin_lock(struct bpf_verifier_env *env, int regno,
      
      static bool arg_type_is_mem_ptr(enum bpf_arg_type type)
      {
    @@ kernel/bpf/verifier.c: static const struct bpf_reg_types *compatible_reg_types[_
      	[ARG_PTR_TO_INT]		= &int_ptr_types,
      	[ARG_PTR_TO_LONG]		= &int_ptr_types,
      	[ARG_PTR_TO_PERCPU_BTF_ID]	= &percpu_btf_ptr_types,
    - 	[ARG_PTR_TO_FUNC]		= &func_ptr_types,
    --	[ARG_PTR_TO_STACK_OR_NULL]	= &stack_ptr_types,
    -+	[ARG_PTR_TO_STACK]		= &stack_ptr_types,
    - 	[ARG_PTR_TO_CONST_STR]		= &const_str_ptr_types,
    - 	[ARG_PTR_TO_TIMER]		= &timer_types,
    - };
     @@ kernel/bpf/verifier.c: static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
      	const struct bpf_reg_types *compatible;
      	int i, j;
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-5.15.y       |  Success    |  Success   |