Thread (3 messages) 3 messages, 3 authors, 2022-11-09

Re: [PATCH] arm64/syscall: Include asm/ptrace.h in syscall_wrapper header.

From: Andrii Nakryiko <hidden>
Date: 2022-11-04 21:13:05
Also in: bpf, lkml

On Mon, Oct 31, 2022 at 2:57 PM Kuniyuki Iwashima [off-list ref] wrote:
Add the same change for ARM64 as done in the commit 9440c4294160
("x86/syscall: Include asm/ptrace.h in syscall_wrapper header") to
make sure all syscalls see 'struct pt_regs' definition and resulted
BTF for '__arm64_sys_*(struct pt_regs *regs)' functions point to
actual struct.

Without this patch, the BPF verifier refuses to load a tracing prog
which accesses pt_regs.

  bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = -1 EACCES

With this patch, we can see the correct error, which saves us time
in debugging the prog.

  bpf(BPF_PROG_LOAD, {prog_type=0x1a, ...}, 128) = 4
  bpf(BPF_RAW_TRACEPOINT_OPEN, {raw_tracepoint={name=NULL, prog_fd=4}}, 128) = -1 ENOTSUPP

Signed-off-by: Kuniyuki Iwashima <redacted>
---
Some of these problems will be mitigated by [0], but still good to
have completely types if possible. LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>

  [0] https://patchwork.kernel.org/project/netdevbpf/list/?series=691488&state=*
quoted hunk ↗ jump to hunk
Note the cited commit only exists in the tip tree for now.
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=9440c42941606af4c379afa3cf8624f0dc43a629
---
 arch/arm64/include/asm/syscall_wrapper.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/syscall_wrapper.h b/arch/arm64/include/asm/syscall_wrapper.h
index b383b4802a7b..d30217c21eff 100644
--- a/arch/arm64/include/asm/syscall_wrapper.h
+++ b/arch/arm64/include/asm/syscall_wrapper.h
@@ -8,7 +8,7 @@
 #ifndef __ASM_SYSCALL_WRAPPER_H
 #define __ASM_SYSCALL_WRAPPER_H

-struct pt_regs;
+#include <asm/ptrace.h>

 #define SC_ARM64_REGS_TO_ARGS(x, ...)                          \
        __MAP(x,__SC_ARGS                                       \
--
2.30.2
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