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From:   Jiri Olsa <jolsa@kernel.org>
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>
Cc:     Akihiro HARAI <jharai0815@gmail.com>, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>
Subject: [PATCH] x86: Include asm/ptrace.h in syscall_wrapper header
Date:   Tue, 18 Oct 2022 14:27:08 +0200
Message-Id: <20221018122708.823792-1-jolsa@kernel.org>
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From: Jiri Olsa <olsajiri@gmail.com>

With just the forward declaration of the 'struct pt_regs' in
syscall_wrapper.h, the syscall stub functions:

  __[x64|ia32]_sys_*(struct pt_regs *regs)

will have different definition of 'regs' argument in BTF data
based on which object file they are defined in.

If the syscall's object includes 'struct pt_regs' definition,
the BTF argument data will point to 'struct pt_regs' record,
like:

  [226] STRUCT 'pt_regs' size=168 vlen=21
         'r15' type_id=1 bits_offset=0
         'r14' type_id=1 bits_offset=64
         'r13' type_id=1 bits_offset=128
  ...

If not, it will point to fwd declaration record:

  [15439] FWD 'pt_regs' fwd_kind=struct

and make bpf tracing program hooking on those functions unable
to access fields from 'struct pt_regs'.

Including asm/ptrace.h directly in syscall_wrapper.h to make
sure all syscalls see 'struct pt_regs' definition and resulted
BTF for '__*_sys_*(struct pt_regs *regs)' functions point to
actual struct, not just forward declaration.

Reported-by: Akihiro HARAI <jharai0815@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 arch/x86/include/asm/syscall_wrapper.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 59358d1bf880..fd2669b1cb2d 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -6,7 +6,7 @@
 #ifndef _ASM_X86_SYSCALL_WRAPPER_H
 #define _ASM_X86_SYSCALL_WRAPPER_H
 
-struct pt_regs;
+#include <asm/ptrace.h>
 
 extern long __x64_sys_ni_syscall(const struct pt_regs *regs);
 extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
-- 
2.37.3