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
