From: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
To: bpf@vger.kernel.org
Cc: Siddharth Chintamaneni <sidchintamaneni@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
Anton Protopopov <a.s.protopopov@gmail.com>,
Puranjay Mohan <puranjay@kernel.org>,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-riscv@lists.infradead.org, rlmenge@gmail.com,
hargar@linux.microsoft.com, apais@microsoft.com
Subject: [PATCH bpf-next v1 7/7] selftests/bpf: Test timed may_goto with private stacks
Date: Fri, 4 Sep 2026 19:51:32 +0000 [thread overview]
Message-ID: <20260904195132.141068-8-sidchintamaneni@gmail.com> (raw)
In-Reply-To: <20260904195132.141068-1-sidchintamaneni@gmail.com>
Add private_stack_timed_may_goto() with enough stack usage to select a
private stack. Check that the JIT uses the private-stack frame pointer
when constructing the pointer passed to the architecture trampoline.
Update the translated instruction expectations in may_goto_batch_2(),
may_goto_interaction_x86_64(), and may_goto_interaction() for the
additional pointer construction instruction and adjusted branch offsets.
Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
---
.../bpf/progs/verifier_bpf_fastcall.c | 30 ++++++++++---------
.../selftests/bpf/progs/verifier_may_goto_1.c | 17 ++++++-----
.../bpf/progs/verifier_private_stack.c | 19 ++++++++++++
3 files changed, 44 insertions(+), 22 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c
index 328cf630210a..c5996d9dc8cc 100644
--- a/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c
+++ b/tools/testing/selftests/bpf/progs/verifier_bpf_fastcall.c
@@ -635,15 +635,16 @@ __xlated("4: r0 = &(void __percpu *)(r0)")
__xlated("...")
/* may_goto expansion starts */
__xlated("6: r12 = *(u64 *)(r10 -24)")
-__xlated("7: if r12 == 0x0 goto pc+6")
+__xlated("7: if r12 == 0x0 goto pc+7")
__xlated("8: r12 -= 1")
-__xlated("9: if r12 != 0x0 goto pc+2")
-__xlated("10: r12 = -24")
-__xlated("11: call unknown")
-__xlated("12: *(u64 *)(r10 -24) = r12")
+__xlated("9: if r12 != 0x0 goto pc+3")
+__xlated("10: r12 = r10")
+__xlated("11: r12 += -24")
+__xlated("12: call unknown")
+__xlated("13: *(u64 *)(r10 -24) = r12")
/* may_goto expansion ends */
-__xlated("13: *(u64 *)(r10 -8) = r1")
-__xlated("14: exit")
+__xlated("14: *(u64 *)(r10 -8) = r1")
+__xlated("15: exit")
__success
__naked void may_goto_interaction_x86_64(void)
{
@@ -676,15 +677,16 @@ __xlated("2: r1 = 1")
__xlated("3: call bpf_get_smp_processor_id")
/* may_goto expansion starts */
__xlated("4: r12 = *(u64 *)(r10 -24)")
-__xlated("5: if r12 == 0x0 goto pc+6")
+__xlated("5: if r12 == 0x0 goto pc+7")
__xlated("6: r12 -= 1")
-__xlated("7: if r12 != 0x0 goto pc+2")
-__xlated("8: r12 = -24")
-__xlated("9: call unknown")
-__xlated("10: *(u64 *)(r10 -24) = r12")
+__xlated("7: if r12 != 0x0 goto pc+3")
+__xlated("8: r12 = r10")
+__xlated("9: r12 += -24")
+__xlated("10: call unknown")
+__xlated("11: *(u64 *)(r10 -24) = r12")
/* may_goto expansion ends */
-__xlated("11: *(u64 *)(r10 -8) = r1")
-__xlated("12: exit")
+__xlated("12: *(u64 *)(r10 -8) = r1")
+__xlated("13: exit")
__success
__naked void may_goto_interaction(void)
{
diff --git a/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c b/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c
index db7e30da234f..1721897160dc 100644
--- a/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c
+++ b/tools/testing/selftests/bpf/progs/verifier_may_goto_1.c
@@ -90,15 +90,16 @@ __arch_loongarch
__xlated("0: *(u64 *)(r10 -16) = 65535")
__xlated("1: *(u64 *)(r10 -8) = 0")
__xlated("2: r12 = *(u64 *)(r10 -16)")
-__xlated("3: if r12 == 0x0 goto pc+6")
+__xlated("3: if r12 == 0x0 goto pc+7")
__xlated("4: r12 -= 1")
-__xlated("5: if r12 != 0x0 goto pc+2")
-__xlated("6: r12 = -16")
-__xlated("7: call unknown")
-__xlated("8: *(u64 *)(r10 -16) = r12")
-__xlated("9: r0 = 1")
-__xlated("10: r0 = 2")
-__xlated("11: exit")
+__xlated("5: if r12 != 0x0 goto pc+3")
+__xlated("6: r12 = r10")
+__xlated("7: r12 += -16")
+__xlated("8: call unknown")
+__xlated("9: *(u64 *)(r10 -16) = r12")
+__xlated("10: r0 = 1")
+__xlated("11: r0 = 2")
+__xlated("12: exit")
__success
__naked void may_goto_batch_2(void)
{
diff --git a/tools/testing/selftests/bpf/progs/verifier_private_stack.c b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
index 3d9994a52464..639b53363c9a 100644
--- a/tools/testing/selftests/bpf/progs/verifier_private_stack.c
+++ b/tools/testing/selftests/bpf/progs/verifier_private_stack.c
@@ -70,6 +70,25 @@ __naked void no_private_stack_nested(void)
" ::: __clobber_all);
}
+SEC("fentry/bpf_fentry_test9")
+__description("Private stack, timed may_goto")
+__success __retval(0)
+__arch_x86_64
+__jited(" movabsq $0x{{.*}}, %r9")
+__jited("...")
+__jited(" movq %r9, %r10")
+__arch_arm64
+__jited(" mov x9, x25")
+int private_stack_timed_may_goto(void)
+{
+ volatile __u64 stack_space[16] = {};
+
+ while (can_loop)
+ ;
+
+ return stack_space[0];
+}
+
__used
__naked static void cumulative_stack_depth_subprog(void)
{
--
2.43.0
prev parent reply other threads:[~2026-09-05 6:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 19:51 [PATCH bpf-next v1 0/7] Fix timed may_goto with private stacks Siddharth Chintamaneni
2026-09-04 19:51 ` [PATCH bpf-next v1 1/7] bpf: Fix timed may_goto stack pointer for " Siddharth Chintamaneni
2026-09-04 19:51 ` [PATCH bpf-next v1 2/7] bpf, x86: Use resolved pointer for timed may_goto Siddharth Chintamaneni
2026-09-04 20:33 ` bot+bpf-ci
2026-09-09 16:34 ` Siddharth Chintamaneni
2026-09-04 19:51 ` [PATCH bpf-next v1 3/7] bpf, arm64: " Siddharth Chintamaneni
2026-09-04 19:51 ` [PATCH bpf-next v1 4/7] bpf, powerpc64: " Siddharth Chintamaneni
2026-09-04 19:51 ` [PATCH bpf-next v1 5/7] bpf, riscv: " Siddharth Chintamaneni
2026-09-04 20:33 ` bot+bpf-ci
2026-09-04 19:51 ` [PATCH bpf-next v1 6/7] bpf, s390: " Siddharth Chintamaneni
2026-09-04 20:33 ` bot+bpf-ci
2026-09-04 19:51 ` Siddharth Chintamaneni [this message]
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