bpf, riscv: Fix stack-passed arguments for indirect trampolines

store_args() reads stack-passed arguments relative to FP assuming the
trampoline was entered through the fentry call from a traced function. In
that path, the trampoline pushes the parent frame before establishing its
final FP, so the incoming stack arguments start at FP + 16.

An indirect trampoline for a struct_ops callback is called through a
function pointer. Its prologue allocates only the trampoline frame and sets
FP to the incoming SP. The RISC-V ABI places the first stack argument at
that incoming SP, so the arguments start at FP, not FP + 16. Every
stack-passed argument of a callback with more than eight argument slots is
therefore read two slots late.

Pass the prologue-dependent offset to store_args(), using zero for a direct
struct_ops trampoline and 16 for the fentry path.

Fixes: 6801b0aef79d ("riscv, bpf: Add 12-argument support for RV64 bpf trampoline")
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20260930083522.1914145-2-pulehui@huaweicloud.com

0 files changed, 0 insertions, 0 deletions