On 2024/10/9 16:33, Björn Töpel wrote:
Pu Lehui <pulehui@xxxxxxxxxxxxxxx> writes:
From: Pu Lehui <pulehui@xxxxxxxxxx>
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@xxxxxxxxxx>
Thanks! Did you test this with the selftest suite? Did the tailcall
tests catch it?
Oh, I discovered it through code review.
I just tried llvm compilation but it seems that my environment cannot
compile bpf selftests. I need to find why.
But after reading the tailcalls testcase, I found that the tailcall_3
subtest can cover this scenario as it will verify the TCC value.
Note to self is that I should run kCFI enabled tests for RISC-V.
Acked-by: Björn Töpel <bjorn@xxxxxxxxxx>
