[PATCH v4 1/2] powerpc64/bpf: fix tail calls for PCREL addressing

Michael Ellerman patch-notifications at ellerman.id.au
Wed May 8 23:39:45 AEST 2024


On Thu, 02 May 2024 23:02:04 +0530, Hari Bathini wrote:
> With PCREL addressing, there is no kernel TOC. So, it is not setup in
> prologue when PCREL addressing is used. But the number of instructions
> to skip on a tail call was not adjusted accordingly. That resulted in
> not so obvious failures while using tailcalls. 'tailcalls' selftest
> crashed the system with the below call trace:
> 
>   bpf_test_run+0xe8/0x3cc (unreliable)
>   bpf_prog_test_run_skb+0x348/0x778
>   __sys_bpf+0xb04/0x2b00
>   sys_bpf+0x28/0x38
>   system_call_exception+0x168/0x340
>   system_call_vectored_common+0x15c/0x2ec
> 
> [...]

Applied to powerpc/next.

[1/2] powerpc64/bpf: fix tail calls for PCREL addressing
      https://git.kernel.org/powerpc/c/2ecfe59cd7de1f202e9af2516a61fbbf93d0bd4d
[2/2] powerpc/bpf: enable kfunc call
      https://git.kernel.org/powerpc/c/61688a82e047a4166436bf2665716cc070572ffa

cheers


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