From: Yonghong Song <yonghong.song@linux.dev>
Date: Wed, 13 May 2026 04:51:14 +0000 (-0700)
Subject: bpf: Disable private stack for x86_64 if stack arguments used
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cb6af5314056cb06456cfa8774aa158d61929bcd;p=thirdparty%2Flinux.git

bpf: Disable private stack for x86_64 if stack arguments used

Other architectures like arm64, riscv, etc. have enough register
and for them private stack can be used together with
stack arguments.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260513045114.2392291-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index a10cc045057db..82b9531f87f67 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5163,7 +5163,10 @@ process_func:
 	}
 
 	subprog_depth = round_up_stack_depth(env, subprog[idx].stack_depth);
-	if (priv_stack_supported) {
+	if (IS_ENABLED(CONFIG_X86_64) && subprog[idx].stack_arg_cnt) {
+		/* x86-64 uses R9 for both private stack frame pointer and arg6. */
+		subprog[idx].priv_stack_mode = NO_PRIV_STACK;
+	} else if (priv_stack_supported) {
 		/* Request private stack support only if the subprog stack
 		 * depth is no less than BPF_PRIV_STACK_MIN_SIZE. This is to
 		 * avoid jit penalty if the stack usage is small.