Re: [PATCH] bpf: skip invalid kfunc call in backtrack_insn

From: patchwork-bot+netdevbpf
Date: Fri Jan 06 2023 - 13:00:52 EST


Hello:

This patch was applied to bpf/bpf.git (master)
by Daniel Borkmann <daniel@xxxxxxxxxxxxx>:

On Wed, 4 Jan 2023 09:47:09 +0800 you wrote:
> The verifier skips invalid kfunc call in check_kfunc_call(), which
> would be captured in fixup_kfunc_call() if such insn is not
> eliminated by dead code elimination. However, this can lead to the
> following warning in backtrack_insn(), alse see [1]:
>
> ------------[ cut here ]------------
> verifier backtracking bug
> WARNING: CPU: 6 PID: 8646 at kernel/bpf/verifier.c:2756 backtrack_insn
> kernel/bpf/verifier.c:2756
> __mark_chain_precision kernel/bpf/verifier.c:3065
> mark_chain_precision kernel/bpf/verifier.c:3165
> adjust_reg_min_max_vals kernel/bpf/verifier.c:10715
> check_alu_op kernel/bpf/verifier.c:10928
> do_check kernel/bpf/verifier.c:13821 [inline]
> do_check_common kernel/bpf/verifier.c:16289
> ...
>
> [...]

Here is the summary with links:
- bpf: skip invalid kfunc call in backtrack_insn
https://git.kernel.org/bpf/bpf/c/d3178e8a434b

You are awesome, thank you!
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