LoongArch: BPF: Fix the tailcall hierarchy
authorHaoran Jiang <jianghaoran@kylinos.cn>
Tue, 5 Aug 2025 11:00:22 +0000 (19:00 +0800)
committerHuacai Chen <chenhuacai@loongson.cn>
Tue, 5 Aug 2025 11:00:22 +0000 (19:00 +0800)
commitc0fcc955ff827431b541b1aa6bcb82bdce4531f7
treee4d83f7d74d1b2922371cb6507b4e536ca64efc8
parentcd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3
LoongArch: BPF: Fix the tailcall hierarchy

In specific use cases combining tailcalls and BPF-to-BPF calls,
MAX_TAIL_CALL_CNT won't work because of missing tail_call_cnt
back-propagation from callee to caller. This patch fixes this
tailcall issue caused by abusing the tailcall in bpf2bpf feature
on LoongArch like the way of "bpf, x64: Fix tailcall hierarchy".

Push tail_call_cnt_ptr and tail_call_cnt into the stack,
tail_call_cnt_ptr is passed between tailcall and bpf2bpf,
uses tail_call_cnt_ptr to increment tail_call_cnt.

Fixes: bb035ef0cc91 ("LoongArch: BPF: Support mixing bpf2bpf and tailcalls")
Reviewed-by: Geliang Tang <geliang@kernel.org>
Reviewed-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Haoran Jiang <jianghaoran@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
arch/loongarch/net/bpf_jit.c