[PATCH bpf] riscv, bpf: Fix possible infinite tailcall when CONFIG_CFI_CLANG is enabled

[Björn Töpel]

Pu Lehui <pulehui at huaweicloud.com> writes:

> From: Pu Lehui <pulehui at huawei.com>
>
> When CONFIG_CFI_CLANG is enabled, the number of prologue instructions
> skipped by tailcall needs to include the kcfi instruction, otherwise the
> TCC will be initialized every tailcall is called, which may result in
> infinite tailcalls.
>
> Fixes: e63985ecd226 ("bpf, riscv64/cfi: Support kCFI + BPF on riscv64")
> Signed-off-by: Pu Lehui <pulehui at huawei.com>

Thanks! Did you test this with the selftest suite? Did the tailcall
tests catch it?

Note to self is that I should run kCFI enabled tests for RISC-V.


Acked-by: Björn Töpel <bjorn at kernel.org>