From c560591408440f441b8b327f5b41f9328d20b67b Mon Sep 17 00:00:00 2001 From: "Paul E. Murphy" Date: Tue, 15 Sep 2020 14:18:28 -0500 Subject: [PATCH] libgo: fix ptrace syscall hooks into glibc ptrace is actually declared as a variadic function. On ppc64le the ABI requires to the caller to allocate space for the parameters and allows the caller to modify them. On ppc64le, depending on how and what version of GCC is used, it will save to parameter save area. This happened to clobber a saved LR, and caused syscall.TestExecPtrace to fail with a timeout when the tracee segfaults, and waits for the parent process to inspect. Wrap this function to avoid directly calling glibc's ptrace from go. Fixes golang/go#36698 Fixes go/92567 Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/254755 --- gcc/go/gofrontend/MERGE | 2 +- libgo/go/syscall/libcall_glibc.go | 2 +- libgo/go/syscall/libcall_linux.go | 2 +- libgo/runtime/go-varargs.c | 16 ++++++++++++++++ 4 files changed, 19 insertions(+), 3 deletions(-) diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index df9d2118dfd..6b590f6fd94 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -a47485cd0e9ce6a8b3e88e53ccc0a440f0bd4351 +6fd6418efb983827717f648a11bb5ca6fe93af30 The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/libgo/go/syscall/libcall_glibc.go b/libgo/go/syscall/libcall_glibc.go index a90fc9b3f8b..823343d5075 100644 --- a/libgo/go/syscall/libcall_glibc.go +++ b/libgo/go/syscall/libcall_glibc.go @@ -32,7 +32,7 @@ func Futimes(fd int, tv []Timeval) (err error) { } //sys ptrace(request int, pid int, addr uintptr, data uintptr) (err error) -//ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long +//__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long //sys accept4(fd int, sa *RawSockaddrAny, len *Socklen_t, flags int) (nfd int, err error) //accept4(fd _C_int, sa *RawSockaddrAny, len *Socklen_t, flags _C_int) _C_int diff --git a/libgo/go/syscall/libcall_linux.go b/libgo/go/syscall/libcall_linux.go index 88286c07b6e..78fda0ea7ef 100644 --- a/libgo/go/syscall/libcall_linux.go +++ b/libgo/go/syscall/libcall_linux.go @@ -11,7 +11,7 @@ import ( ) //sysnb raw_ptrace(request int, pid int, addr *byte, data *byte) (err Errno) -//ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long +//__go_ptrace(request _C_int, pid Pid_t, addr *byte, data *byte) _C_long func ptracePeek(req int, pid int, addr uintptr, out []byte) (count int, err error) { // The peek requests are machine-size oriented, so we wrap it diff --git a/libgo/runtime/go-varargs.c b/libgo/runtime/go-varargs.c index 2b186ef8b81..f9270a97bfd 100644 --- a/libgo/runtime/go-varargs.c +++ b/libgo/runtime/go-varargs.c @@ -18,6 +18,9 @@ #ifdef HAVE_SYS_SYSCALL_H #include #endif +#ifdef HAVE_SYS_PTRACE_H +#include +#endif /* The syscall package calls C functions. The Go compiler can not represent a C varargs functions. On some systems it's important @@ -110,3 +113,16 @@ __go_syscall6(uintptr_t flag, uintptr_t a1, uintptr_t a2, uintptr_t a3, } #endif + +#ifdef HAVE_SYS_PTRACE_H + +// Despite documented appearances, this is actually implemented as +// a variadic function within glibc. + +long +__go_ptrace(int request, pid_t pid, uintptr_t addr, uintptr_t data) +{ + return ptrace (request, pid, addr, data); +} + +#endif -- 2.30.2