[PATCH bpf-next v1] bpf, x86: Fix objtool warning for timed may_goto

[PATCH bpf-next v1] bpf, x86: Fix objtool warning for timed may_goto

[Kumar Kartikeya Dwivedi]

Kernel test robot reported "call without frame pointer save/setup"
warning in objtool. This will make stack traces unreliable on
CONFIG_UNWINDER_FRAME_POINTER=y, however it works on
CONFIG_UNWINDER_ORC=y. Fix this by creating a stack frame for the
function.

Fixes: 2cb0a5215274 ("bpf, x86: Add x86 JIT support for timed may_goto")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202503071350.QOhsHVaW-lkp@intel.com/
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
---
 arch/x86/net/bpf_timed_may_goto.S | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/arch/x86/net/bpf_timed_may_goto.S b/arch/x86/net/bpf_timed_may_goto.S
index 20de4a14dc4c..54c690cae190 100644
--- a/arch/x86/net/bpf_timed_may_goto.S
+++ b/arch/x86/net/bpf_timed_may_goto.S
@@ -11,6 +11,16 @@
 SYM_FUNC_START(arch_bpf_timed_may_goto)
 	ANNOTATE_NOENDBR

+	/*
+	 * r10 passes us stack depth, load the pointer to count and timestamp
+	 * into r10 by adding it to BPF frame pointer.
+	 */
+	leaq (%rbp, %r10, 1), %r10
+
+	/* Setup frame. */
+	pushq %rbp
+	movq %rsp, %rbp
+
 	/* Save r0-r5. */
 	pushq %rax
 	pushq %rdi
@@ -20,10 +30,10 @@ SYM_FUNC_START(arch_bpf_timed_may_goto)
 	pushq %r8

 	/*
-	 * r10 passes us stack depth, load the pointer to count and timestamp as
-	 * first argument to the call below.
+	 * r10 has the pointer to count and timestamp, pass it as first
+	 * argument.
 	 */
-	leaq (%rbp, %r10, 1), %rdi
+	movq %r10, %rdi

 	/* Emit call depth accounting for call below. */
 	CALL_DEPTH_ACCOUNT
@@ -40,5 +50,6 @@ SYM_FUNC_START(arch_bpf_timed_may_goto)
 	popq %rdi
 	popq %rax

+	leave
 	RET
 SYM_FUNC_END(arch_bpf_timed_may_goto)
--
2.47.1

Re: [PATCH bpf-next v1] bpf, x86: Fix objtool warning for timed may_goto

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Fri, 14 Mar 2025 18:30:39 -0700 you wrote:
> Kernel test robot reported "call without frame pointer save/setup"
> warning in objtool. This will make stack traces unreliable on
> CONFIG_UNWINDER_FRAME_POINTER=y, however it works on
> CONFIG_UNWINDER_ORC=y. Fix this by creating a stack frame for the
> function.
> 
> Fixes: 2cb0a5215274 ("bpf, x86: Add x86 JIT support for timed may_goto")
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202503071350.QOhsHVaW-lkp@intel.com/
> Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
> 
> [...]

Here is the summary with links:
  - [bpf-next,v1] bpf, x86: Fix objtool warning for timed may_goto
    https://git.kernel.org/bpf/bpf-next/c/812f7702d83d

You are awesome, thank you!
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