Re: [PATCH stable 6.12 4/8] bpf: check changes_pkt_data property for extension programs

[Sasha Levin <sashal@kernel.org>]

[ Sasha's backport helper bot ]

Hi,

Summary of potential issues:
ℹ️ This is part 4/8 of a series
⚠️ Found follow-up fixes in mainline

The upstream commit SHA1 provided is correct: 81f6d0530ba031b5f038a091619bf2ff29568852

WARNING: Author mismatch between patch and upstream commit:
Backport author: Shung-Hsi Yu<shung-hsi.yu@suse.com>
Commit author: Eduard Zingerman<eddyz87@gmail.com>

Status in newer kernel trees:
6.14.y | Present (exact SHA1)

Found fixes commits:
ac6542ad9275 bpf: fix null dereference when computing changes_pkt_data of prog w/o subprogs

Note: The patch differs from the upstream commit:
---
1:  81f6d0530ba03 ! 1:  55bebf976e68c bpf: check changes_pkt_data property for extension programs
    @@ Metadata
      ## Commit message ##
         bpf: check changes_pkt_data property for extension programs
     
    +    commit 81f6d0530ba031b5f038a091619bf2ff29568852 upstream.
    +
         When processing calls to global sub-programs, verifier decides whether
         to invalidate all packet pointers in current state depending on the
         changes_pkt_data property of the global sub-program.
    @@ Commit message
         Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
         Link: https://lore.kernel.org/r/20241210041100.1898468-6-eddyz87@gmail.com
         Signed-off-by: Alexei Starovoitov <ast@kernel.org>
    +    [ shung-hsi.yu: both jits_use_priv_stack and priv_stack_requested fields are
    +    missing from context because "bpf: Support private stack for bpf progs" series
    +    is not present.]
    +    Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
     
      ## include/linux/bpf.h ##
     @@ include/linux/bpf.h: struct bpf_prog_aux {
    + 	bool exception_cb;
    + 	bool exception_boundary;
      	bool is_extended; /* true if extended by freplace program */
    - 	bool jits_use_priv_stack;
    - 	bool priv_stack_requested;
     +	bool changes_pkt_data;
      	u64 prog_array_member_cnt; /* counts how many times as member of prog_array */
      	struct mutex ext_mutex; /* mutex for is_extended and prog_array_member_cnt */
---

NOTE: These results are for this patch alone. Full series testing will be
performed when all parts are received.

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.14.y       |  Success    |  Success   |